Molecular and Cellular Biology

MOLECULAR AND CELLULAR BIOLOGY

VOLUME 3 * NUMBER 1 o JANUARY 1983 Aaron J. Shatkin, Editor-in-Chief (1985) Roche Instituite of Molecular Biology Nutlex, N.J. Harvey F. Lodish, Editor (1986) Louis Siminovitch, Editor (1985) Massachuisetts Institute of Technology Hospital for Sick Children Cambridge Toronto, Canadal David J. L. Luck, Editor (1987) Paul S. Sypherd, Editor (1985) Rockefeller Unis'ersity University of California Ness York, N.Y. Irvine

EDITORIAL BOARD Renato Baserga (1985) Ira Herskowitz (1984) Daniel B. Rifkin (1985) Alan Bernstein (1984) Larry Kedes (1985) Robert G. Roeder (1985) J. Michael Bishop (1984) Marilyn Kozak (1985) James E. Rothman (1984) Joan Brugge (1985) Elias Lazarides (1985) David Sabatini (1985) Breck Byers (1985) John B. Little (1985) Phillip A. Sharp (1985) John A. Carbon (1984) William F. Loomis, Jr. (1985) Fred Sherman (1985) Lawrence A. Chasin (1985) Paul T. Magee (1985) Pamela Stanley (1985) Nam-Hai Chua (1985) Robert L. Metzenberg (1985) Joan A. Steitz (1985) Terrance G. Cooper (1984) Robert K. Mortimer (1985) James L. Van Etten (1985) James E. Darnell, Jr. (1985) Harvey L. Ozer (1985) Jonathan R. Warner (1984) Gary Felsenfeld (1985) Mary Lou Pardue (1985) Robert A. Weinberg (1984) Norton B. Gilula (1985) Mark Pearson (1985) I. Bernard Weinstein (1985) James E. Haber (1984) Jeremy Pickett-Heaps (1985) Harold Weintraub (1985) Benjamin Hall (1985) Robert E. Pollack (1985) Reed B. Wickner (1985) Ari Helenius (1984) Keith R. Porter (1985) Leslie Wilson (1985) Susan A. Henry (1985) John R. Pringle (1985) Edward Ziff (1985)

Helen R. Whiteley, Chairman, Publications Board Walter G. Peter III, Director, Puiblications Linda M. Illig, Managing Editor, Jouirnals Eleanor Tupper, Production Editor

Molecular and Cellular Biology (ISSN 0270-7306) is devoted to the advancement and dissemination of fundamental knowledge concerning the molecular biofogy of eucaryotic cells, of both microbial and higher organisms. Instructions to authors are published in the January issue each year; reprints are available from the editors and the Publications Office. The journal is published monthly, one volume per year. The nonmember subscription price is $84 per year: single copies are $9. The member subscription price is $22 (foreign $26 [surface rate]) per year; single copies are $7. Correspondence relating to subscriptions. reprints. defective copies, availability of back issues, lost or late proofs, disposition of submitted manuscripts, and general editorial matters should be directed to the ASM Publication Office, 1913 I St., NW, Washington, DC 20006 (area 202 833-9680). Claims for missing issues from residents of the United States, Canada, and Mexico must be submitted within 3 months after publication of the issues; residents of all other countries must submit claims within 6 months of publication of the issues. Claims for issues missing because of failure to report an address change or for issues "missing from files" will not be allowed. Second-class postage paid at Washington, DC 20006, and at additional mailing offices. POSTMASTER: Send address changes to Molecular and Cellular Biology, ASM, 1913 I St., NW, Washington, DC 20006. Made in the United States of America. Copyright ©C 1983, American Society for Microbiology. El*: fl M1 4It hc,f L 'I r, l1tO All Rights Reserved. The code at the top of the first page of an article in this journal indicates the copyright owner's consent that copies of the article may be made for personal use or for personal use of specific clients. This consent is given on the condition, however, that the copier pay the stated per-copy fee through the Copyright Clearance Center Inc., 21 Congress St., Salem, MA 01970, for copying beyond that permitted by Sections 107 and 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying, such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale. Author Index

Baglioni, Corrado, 64 Kaufman, Randal J., 32 Russell, David W., 20 Boettiger, D., 113 Khandjian, Edouard W., 1 Brugge, Joan, 9 Scher, Charles D., 70 Latt, Samuel A., 32 Sefton, Bartholomew M., 56 Chung-Cheng, Liu, 44 Levinson, Arthur D., 44 Siddiqui, Aleem, 143 Cooper, Jonathan A., 56 Levy, Barcey T., 102 Smith, Michael, 20 Cox, David, 20 Locatell, Kathryn L., 70 Crowley, Craig W., 44 Stieber, Anna, 91

Maness, Patricia F., 102 Darrow, Diane, 9 Maroney, Patricia A., 64 Tannenbaum, Janet, 132 Dick, Ronald L., 70 Menko, A. S., 113 Toyama, Y., 113 Mertz, Janet E., 126 Turler, Hans, 1 Miller, Timothy J., 126 Fishmann, P. H., 91 Mommol, T., 91 Murray, Mark J., 32 Weinberg, Robert A., 32 Godman, Gabriel C., 132 Whipple, Andrew P., 70 Gonatas, J., 91 Williamson, Valerie M., 20 Gonatas, Nicholas K., 91 Nilsen, Timothy W., 64 Wohlhueter, Robert M., 82

Holtzer, H., 113 Plagemann, Peter G. W., 82 Yonemoto, Wes, 9 Hunter, Tony, 56 Puziss, Marla B., 82 Young, Elton T., 20 MOLECULAR AND CELLULAR BIOLOGY, Jan. 1983 MOLECULAR AND CELLULAR BIOLOGY INSTRUCTIONS TO AUTHORS HOW TO SUBMIT MANUSCRIPTS ASM publishes a number of different journals Submit manuscripts directly to the ASM Pub- covering various aspects of microbiology. Each journal has a prescribed scope that must be lications Office, 1913 I St., NW, Washington, DC 20006. Please indicate the journal to which considered in determining the most appropriate the manuscript is being submitted, the address journal for each manuscript. If a given manu- and telephone number of the corresponding au- script is appropriate for more than one ASM thor, and the former manuscript number and journal, the author's wishes will be given pri- editor (if it is being resubmitted). In addition, mary consideration. However, the editors re- indicate whether permission to cite personal serve the option of transferring a manuscript to communications and receipt of preprints has another ASMjournal when it is apparent that the been granted. manuscript falls within the province of that Submit two complete copies of each manu- journal. script, including figures and tables. The manu- The Journal ofBacteriology (JB) is a journal script may be either the original typescript or of basic microbiology, including that of eucary- clear, clean copies. Type every portion of the otic microbes. It contains articles on all aspects manuscript double spaced, including figure leg- of eucaryotic microbes, including genetics and ends, table footnotes, and Literature Cited, and molecular biology, plasmids and transposons, number all pages in sequence, including the physiology, membranes, enzymes, and ultra- abstract, tables, and figure legends. Submit fig- structure. The scope statements for MCB and ures as glossy or mat-finish photographs. (See p. JB are complementary. They provide authors iii-iv for detailed instructions.) with appropriate journals for the publication of Authors who are unsure of acceptable English research covering all aspects of eucaryotic mi- usage should have their manuscripts checked by crobiology. In cases in which a research report someone proficient in the English language. would be equally appropriate for either journal, the author's preference will be followed. EDITORIAL POLICY Most manuscripts concerning virus-infected Manuscripts submitted to the journal must cells should be submitted to the Journal of represent reports of original research that have Virology, but those in which emphasis is clearly not been published previously and that are not on the cell, with the virus being incidental, are being considered for publication elsewhere. appropriate for MCB. If you have questions about these guidelines, Copyright please contact the editor-in-chief of the journal To maintain and protect the Society's owner- you are considering. ship and rights and to be able to protect the Note that a manuscript rejected by one ASM original authors from misappropriation of their journal on scientific grounds or on the basis of published work, ASM requires authors to sign a its general suitability for publication is consid- copyright transfer agreement. This agreement is ered rejected by all other ASM journals. sent to the submitting author when the manuscript is accepted for publication. Unless this Editorial Style agreement is executed, ASM will not publish the The editorial style of ASM journals conforms manuscript. (U.S. government employees may to the Council ofBiology Editors Style Manual file a statement attesting that a manuscript was (4th ed., 1978; CBE Secretariat, 9650 Rockville prepared as part of their official duties. If they Pike, Bethesda, Md.), Robert A. Day's How To elect to do so, they should not sign the ASM Write and Publish a Scientific Paper (ISI Press, copyright transfer agreement.) 1979), and Scientific Writing for Graduate Stu- dents (CBE Secretariat), as interpreted and Scope modified by the editors and the ASM Publica- Molecular and Cellular Biology (MCB) is de- tions Office. The editors and the Publications voted to the advancement and dissemination of Office reserve the privilege of editing manu- fundamental knowledge concerning the molecu- scripts to conform with the stylistic conventions lar biology of eucaryotic cells, of both microbial set forth in the aforesaid publications and in and higher organisms. Papers on cellular mor- these instructions. phology and function, genome organization, the regulation of genetic expression including The Review Process immunoglobulin formation, morphogenesis, and All manuscripts are subjected to peer review somatic cell genetics are invited for submission. by the editors, by members of the Editorial i INSTRUCTIONS TO AUTHORS Board, or by qualified outside reviewers. When the main title/subtitle arrangement. On the title a manuscript is submitted to the journal, it is page, include: title, running title (not to exceed given a manuscript control number and is as- 46 characters and spaces), full name (including signed to one of the editors. The author is first name and middle initial) of each author, notified of this number and the editor to whom address(es) of the institution(s) at which the the manuscript is assigned. Authors are notified, work was performed, and each author's affili- generally within 4 to 6 weeks after submission, ation or a footnote indicating the present address as to acceptance, rejection, or need for modifi- of any author no longer at the institution where cation. When a manuscript is returned to the the work was performed. Place an asterisk after author for modification, it should be returned to the name of the author to whom inquiries regard- the editor within 2 months; otherwise it may be ing the paper should be directed, and give that considered withdrawn. author's telephone number. When a manuscript is accepted for publication, the editor sends the manuscript and a Disclaimers. If a statement disclaiming gov- signed letter of acceptance to the ASM Publica- ernmental or any other type of endorsement or tions Office. The month of publication and ap- approval is included, it will be deleted by the proximate galley date are added to the accep- Publications Office. tance letter, which is then mailed to the author. Abstract. Limit the abstract to 250 words or The editorial staff of the ASM Publications Of- fewer. Summarize the basic content of the pa- fice completes the editing of the manuscript to per. Avoid abbreviations, diagrams, and refer- bring it into conformity with prescribed stan- ences. When it is essential to include a refer- dards. ence, use the full literature citation but omit the Galley Proofs article title. Because the abstract will be published separately by abstracting services, it must The printer sends the galley proof, copy- be complete and understandable without refer- edited manuscript, and reprint order form to the ence to the text. author. As soon as the galleys are corrected (within 48 h), they should be mailed to the ASM Introduction. The introduction should supply Publications Office. sufficient background information to allow the The galley proof stage is not the time to make reader to understand and evaluate the results of extensive corrections, additions, or deletions. If the present study without needing to refer to new information has become available between previous publications on the topic. The intro- acceptance and receipt of the galley proofs, and duction should also provide the rationale for the you feel that it is important to include this present study. Use only those references re- information, insert it as an "Addendum in quired to provide the most salient background Proof" with the permission of the editor. Limit rather than an exhaustive review of the topic. changes to correction of spelling errors, incor- rect data, and serious grammatical errors. "In Materials and Methods. The Materials and press" references for which page numbers have Methods section should include sufficient tech- become available should be placed in the Litera- nical information so that the experiments can be ture Cited section as "a" numbers (e.g., 12a). repeated. For commonly used materials and Do not renumber references. methods (e.g., commonly used media, protein Questions regarding late galleys and problems determinations), a simple reference is sufficient. in the proof should be directed to the ASM If several alternative methodologies are com- Publications Office, telephone 202-833-9680. monly employed, it is useful to identify the method briefly as well as to cite the reference. Reprints For example, it is preferable to state, "cells Reprints (in multiples of 100) may be pur- were broken by ultrasonic treatment as previ- chased by contributors. An order form including ously described (9)," rather than to state, "cells a table showing the cost of reprints is sent with were broken as previously described (9)." You each proof. should allow the reader to assess the methodolo- gy without constant reference to previous publi- ORGANIZATION AND FORMAT cations. Describe new methods completely and Regular Papers give sources of unusual chemicals, equipment, Regular full-length papers should include the or microbial strains. When large numbers of elements described in this section. microbial strains or mutants are used in a study, include strain tables identifying the sources and Title. Each manuscript should present the properties of the strains, mutants, bacterio- results of an independent, cohesive study; thus, phages, plasmids, etc. numbered series titles are not allowed. Avoid A method, strain, etc., used in only one of INSTRUCTIONS TO AUTHORS several experiments reported in the paper Base (BioSciences Information Service, 1981). should be described in the Results section or, if Cite each listed reference in the text by number. brief enough, in a table footnote or figure legend. The following types of references are not val- id for listing: unpublished data, personal com- Results. The Results section should include munications, manuscripts in preparation, man- the results of the experiments. Reserve exten- uscripts submitted, "in press" references, sive interpretation of the results for the Discus- pamphlets, abstracts, patents, theses, disserta- sion section. Present the results as concisely as tions, and material that has not been subjected possible in one of the following: text, table(s), or to peer review. References to such sources figure(s). However, avoid extensive use of should be made parenthetically in the text. An graphs to present data that might be more con- "in press" reference to an ASM journal includ- cisely presented in the text or tables. For exam- ed in Literature Cited should state the control ple, except in unusual cases, double-reciprocal number (e.g., MCB 976) or the month of publica- plots used to determine apparent Km values tion, so that the copy editor can verify the should not be presented as graphs; instead, the reference and include it in the listed references. values should be stated in the text. Similarly, Follow the styles shown in the examples be- graphs illustrating other methods commonly low. used to derive kinetic or physical constants (e.g., reduced viscosity plots, plots used to 1. Clutterbuck, A. J., and D. J. Cove. 1974. Linkage determine sedimentation velocity) need not be map of Aspergillus nidulans, p. 665-676. In A. I. shown except in unusual circumstances. Limit Laskin and H. A. Lechevalier (ed.), Handbook of photographs (particularly photomicrographs and microbiology, vol. 4. CRC Press, Cleveland, Ohio. electron micrographs) to those that are absolute- 2. Liebman, S. W., J. W. Stewart, J. H. Parker, and F. Sherman. 1977. Leucine insertion caused by a ly necessary to demonstrate the experimental yeast amber suppressor. J. Mol. Biol. 109:13-22. findings. Number figures and tables in the order 3. Smith, B. A., and D. D. Burke. 1980. Protein syn- in which they are cited in the text, and be sure to thesis during germination of Allomyces macro- cite all figures and tables. gynus mitospores. J. Bacteriol. 143:1498-1500. Discussion. The Discussion should provide an Parenthetical references in the text should be interpretation of the results in relation to previ- cited as follows: ously published work and to the experimental . . . and protects the organisms against oxygen system at hand and should not contain extensive toxicity (H. P. Misra and I. Fridovich, Fed. repetition of the Results section or reiteration of Proc. 35:1686, 1976). the introduction. In short papers, the Results ... system was used (W. E. Scowcroft, A. H. and Discussion sections may be combined. Gibson, and J. D. Pagan, Biochem. Biophys. Acknowledgments. Acknowledgments for fi- Res. Commun., in press). nancial assistance and for personal assistance ... in linkage group XIV (R. D. Smyth, Ph.D. are given in two separate paragraphs. The usual thesis, University of California, Los Angeles, format for acknowledgment of grant support is 1972). as follows: "This work was supported by Public ... in poly mitochondria (S. E. Mainzer and Health Service grant CA-01234 from the Nation- C. W. Slayman, Abstr. Annu. Meet. Am. Soc. al Cancer Institute." Microbiol. 1976, K5, p. 139). Appendixes. Appendixes, which contain sup- Notes plementary material to aid the reader, are permitted. Titles, authors, and Literature Cited The Note format is intended for the presenta- sections that are distinct from those of the tion of brief observations that do not warrant primary article are not allowed. If it is not full-length papers. Submit Notes in the same feasible to list the author(s) of the appendix in way as full-length papers. They receive the same the by-line or the Acknowledgment section of review, and they are not considered preliminary the primary article, rewrite the appendix so that communications. it can be considered for publication as an inde- Each Note must have an abstract of no more pendent article, either full length or Note style. than 50 words. Do not use section headings in the body of the Note; report methods, results, Literature Cited. Each listed reference must and discussion in a single section. The text is not be cited in the text. Arrange the Literature Cited to exceed 1,000 words, and the number of fig- section in alphabetical order, by first author, and ures and tables should be kept to a minimum. number consecutively. Abbreviate journal Present acknowledgments as in full-length pa- names according to the Bibliographic Guide for pers, but do not use a heading. The Literature Editors and Authors (American Chemical Socie- Cited section is identical to that of full-length ty, 1974) or Serial Sources for the BIOSIS Data papers. IV INSTRUCTIONS TO AUTHORS ILLUSTRATIONS AND TABLES 10-2 U/ml. The preferred designation would be Photographs 60 mU/ml (milliunits per milliliter). When submitting electron micrographs, pho- Figure Legends tographs of polyacrylamide gels, etc., keep in Figure legends may be placed beneath the mind the journal page 6.5 cm a size: for single photocopy of a drawing for the convenience of column and 14 cm for a double column (maxi- reviewers. (In addition, however, a complete set mum). Include only the significant portion of the of illustration. Each must be of contrast photographs or drawings, with legends on sufficient separate pages, must accompany each copy of to withstand the inevitable loss of contrast and the manuscript.) Legends should provide detail inherent in the printing process. Electron enough information so that the figure is under- and light micrographs must be first-generation standable without frequent reference to the text. copies of the original negatives. Indicate the However, do not repeat experimental methods magnification of each photomicrograph with a in the legend. Define all symbols and abbrevia- scale marker on the electron micrograph. Do not tions used in the figure. Common abbreviations mount figures on heavy cardboard. Composite and others used in the preceding text need not be figures may be mounted on bond paper or on redefined in the legend. lightweight, flexible cardboard. A complete set of photographs, not photocopies, must accom- Tables pany each copy of the manuscript. Type each table on a separate page. Arrange Drawings the data so that columns of like material read down, not across. The headings should be suffi- Submit graphs, charts, diagrams, and other ciently clear so that the meaning of the data will drawings as photographs made from finished be understandable without reference to the text. drawings not requiring additional artwork or See Abbreviations in these instructions for those typesetting. No part of the graph or drawing that should be used in tables. Explanatory foot- should be typewritten. Use a lettering set or notes are acceptable, but more extensive table other professional-quality device for all labeling. "legends" are not. Footnotes should not include Most graphs will be reduced to one-column detailed descriptions of the experiment. A well- width (6.5 cm), and all elements in the drawing constructed table is shown below. should be prepared to withstand this reduction. Avoid very heavy letters, which tend to close up when reduced, and unusual symbols, which the TABLE 1. Effect of glucose on levels of catabolic printer may not be able to reproduce in the enzymes and morphology in M. rouxii legend. Direct readouts from computers, record- Enzyme activity ers, etc., are not usually acceptable; such materials should be redrawn. In figure ordinate and abscissa scales (as well Pyruvate Gluta- Cell type kinasea Phos- mate vate de- as table column headings), avoid ambiguous use ph- dehy- vt e of numbers with exponents. Usually, it is prefera- 1 5 kinasebfructo- drogen- carbox-ylase' ble to use the appropriate SI symbols (,u for min min ase' 10-6, m for 10-3, k for 103, M for 106, etc.). A complete listing of SI symbols can be found in Mycelium the IUPAC "Manual of Symbols and Terminolo- -Glucose 1,056 2 1.7 4.3 0.05 gy for Physicochemical Quantities and Units" +Glucose 2,930 10 8.04 0.53 1.3 (Pure Chem. repre- Yeast Appl. 21:3-44, 1970). Thus, +Glucose 4,380 30 63.6 0.03 1.7 sentation of 20,000 cpm on a figure ordinate should be made by the number 20, accompanied a Nanomoles of pyruvate formed per milligram of by the label kcpm. protein in time shown (3, 9). Where powers of 10 must be employed, the b Millimoles of fructose 1,6-diphosphate produced editorial style of the journal follows the CBE per minute per milligram of protein (7). Style Manual recommendation, which differs c Micromoles of NADH oxidized per minute per from the conventions used by several other milligram of protein (10). journals. The CBE Style Manual suggests that the exponent power be associated with the number shown. In representing 2 x 107 cells per ml, Camera-Ready Copy the correct designation would be 2, labeled as Drawings, tables, chemical formulas, etc., 107 cells per ml, not cells per ml x 10-7. that can be photographically reproduced for Likewise, an enzyme activity of 0.06 U/ml publication without further typesetting or would be shown as 6, accompanied by the label artwork are referred to as "camera ready." INSTRUCTIONS TO AUTHORS v Such copy may also be prepared for complicated The nomenclature of bacteria should follow mathematical or physical formulas, portions of that presented in Bergey's Manual of Determi- genetic maps, diagrams, and flow schemes. It native Bacteriology (8th ed., The Williams & should not be hand lettered. Camera-ready copy Wilkins Co., 1974). must be carefully prepared to conform with the Since the classification of fungi is so far from style of the journal. The advantage in submitting complete, it is the responsibility of the author to camera-ready copy is that the material will ap- determine the currently accepted binomial for a pear exactly as envisioned by the author, and no given yeast or mold. Some sources for the second proofreading is necessary. This is partic- spelling of these names include The Yeasts (J. ularly advantageous when there are long, com- Lodder, ed., North-Holland Publishing Co., plicated tables and when the division of material Amsterdam, 1970) and Ainsworth and Bisby's and spacing are important. Dictionary of the Fungi, Including the Lichens, 6th ed. (Commonwealth Mycological Institute, NOMENCLATURE Kew, Surrey, England, 1971). Names used for viruses should be those ap- Chemical and Biochemical Nomenclature proved by the International Committee on Tax- onomy of Viruses (ICTV) and published in the The recognized authority for the names of 3rd Report of the ICTV, Classification and No- chemical compounds is Chemical Abstracts menclature of Viruses (Intervirology, vol. 12, (Chemical Abstracts Service, Ohio State Uni- no. 3-5, 1979). If desired, synonyms may be versity, Columbus) and its indexes. For guide- added parenthetically when the name is first lines to the use of biochemical terminology, mentioned. Approved generic (or group) and consult the following: International Union of family names may also be used. Biochemistry Biochemical Nomenclature and Microorganisms, viruses, and plasmids should Related Documents, 1978, reprinted for The be given designations consisting of letters and Biochemical Society, London, England; the in- serial numbers. It is generally advisable to instructions to authors of the Journal ofBiological clude a worker's initials or a descriptive symbol Chemistry and Archives of Biochemistry and of locale, laboratory, etc., in the designation. Biophysics (first issues of each year); and the Each new strain, mutant, isolate, or derivative Handbook ofBiochemistry and Molecular Biol- should be given a new (serial) designation. Such ogy (G. D. Fasman, ed., 3rd ed., CRC Press, a designation should be distinct from those of Inc., 1976). the genotype and phenotype, and genotypic and Do not express molecular weights in daltons; phenotypic not molecular weight is a unitless ratio. Molecular symbols should be included. mass is expressed in daltons. A registry of plasmid designations is main- For enzymes, use the recommended (trivial) tained by the Plasmid Reference Center, Depart- name assigned by the Nomenclature Committee ment of Medical Microbiology, Stanford Univer- of the International Union of Biochemistry as sity, Stanford, CA 94305. described in Enzyme Nomenclature 1978 (Aca- Genetic Nomenclature demic Press, Inc., 1979). If a nonrecommended name is used, place the proper (trivial) name in Procaryotes. The genetic propeties of procary- parentheses at first use in the abstract and text. otes are described in terms of phenotypes and Use the EC number when it has been assigned, genotypes. The phenotype designation describes and express enzyme activity either in katals the observable properties of an organism. The (preferred) or in the older system of ,umol/min. genotype refers to the genetic constitution of an organism, usually in reference to some standard wild type. In preparing a manuscript, follow the Nomenclature of Microorganisms recommendations of Demerec et al. (Genetics Binary names, consisting of a generic name 54:61-74, 1966) and the practices currently in and a specific epithet (e.g., Escherichia coli), use in the Journal ofBacteriology. must be used for all microorganisms. Names of (i) Phenotype designations must be employed higher categories may be used alone, but a when mutant loci have not been identified or specific epithet must be preceded by a generic mapped. Phenotype designations generally con- name the first time it is used in a paper. Thereaf- sist of three-letter symbols; these are not itali- ter, the generic name should be abbreviated to cized, and the first letter of the symbol is capital- the initial capital letter (e.g., E. coli), provided ized (e.g., Tol). Wild-type characteristics can be there can be no confusion with other genera designated as Tol+ or Pol+ and, when necessary used in the paper. Names of all taxa (phyla [for for clarity, negative superscripts (Tol- Pol-) can fungi, divisions], classes, orders, families, gen- be used to designate mutant characteristics. era, species, subspecies) are printed in italics; Superscript letters may be used to further delin- strain designations and numbers are not. eate phenotypes (e.g., Strs for streptomycin vi INSTRUCTIONS TO AUTHORS sensitivity). Phenotype designations should be such inserted DNA should conform to those defined. employed for the host genome. (ii) Genotype designations are similarly indicated by a three-letter symbol. In contrast to Eucaryotes. The nomenclature used in the phenotype designations, genotype designations genetics of lower eucaryotic microorganisms has are lowercase italic (e.g., ara his rps). If several not been as well formalized as that for bacteria loci govern related functions, these are distin- and bacteriophages. Generally, authors should guished by an italicized capital letter following conform to current practices in identifying mu- the locus symbol (e.g., araA araB). Mutation tants and their genotypes. It is advisable to sites are distinguished by placing serial isolation consult the Handbook of Microbiology (A. I. numbers (allele numbers) after the locus symbol Laskin and H. A. Lechevalier, ed., CRC Press, (e.g., ara-J hisB5). Promoter, terminator, and 1974) or the Handbook of Genetics, vol. 1, operator sites should be indicated as described Bacteria, Bacteriophages, and Fungi (R. C. by Bachmann and Low (Microbiol. Rev. 44:1- King, ed., Plenum Press, 1974) for designations 56, 1980): e.g., lacZp, lacAt, and lacZo. It is currently in use for Neurospora crassa, Asper- essential in papers reporting the isolation of new gillus nidulans, Schizosaccharomyces pombe, mutants that allele numbers be given to the Podospora anserina, Ustilago sp., Schizophyl- mutations. For Escherichia coli, there is a regis- lum commune, Coprinus sp., and Chlamydomo- try of such numbers: E. coli Genetic Stock nas reinhardi. Center, Department of Human Genetics, Yale Genetic designations for Saccharomyces cere- University School of Medicine, P.O. Box 3333, visiae should generally follow the recommenda- New Haven, CT 06510. For Salmonella, the tions of Sherman and Lawrence (Handbook of registry is: Salmonella Genetic Stock Center, Genetics, vol. 1). (i) The two mating-type alleles Department of Biology, University of Calgary, are designated, respectively, by a boldface, Ro- Calgary, Alberta, Canada T2N IN4. man "a" and a Greek "a." (ii) As with bacteria, (iii) Wild-type alleles are indicated with a gene symbols are usually designated by three superscript plus (ara+ his'). Where the geno- italicized letters. In general, the genetic locus is type of an organism is being specified (e.g., in a identified by an arabic numeral following the strain table), a superscript minus is not used to gene symbol (e.g., arg2), whereas alleles are indicate a mutant locus. Elsewhere, a super- designated by an arabic numeral separated from script minus may be used to distinguish between the locus number by a hyphen (e.g., arg2-6). (iii) the symbol of a mutant allele and that of a Complementation groups of a gene are identified genetic locus. However, this distinction is best by capital letters following the locus number made in the context, and thus one refers to an (e.g., his4A). (iv) Dominant and recessive genes ara mutant rather than an ara- strain. are denoted by upper- and lowercase letters, (iv) The use of superscripts with genotypes respectively (e.g., SUP4 and arg2). (v) When (other than + to indicate wild-type alleles) there is no confusion wild-type genes are desig- should be avoided. Designations indicating am- nated simply as +; the + may follow the locus ber mutations, temperature-sensitive mutations, number to designate a specific wild-type gene, and indications of phenotype should follow the e.g., sup6+ and ARG2+. (vi) Although super- allele number [e.g., araA230(Am)]. scripts should be avoided, it is sometimes expe- (v) Avoid the use of a genotype as name (e.g., dient to distinguish genes conferring resistance "subsequent use of leuC6 for transduction"). and sensitivity by the superscripts r and s, If a strain designation has not been chosen, respectively (e.g., canrl CUPsI). (vii) Mito- select an appropriate word combination (e.g., chondrial and non-Mendelian genotypes can be "either strain PA3092 or another strain contain- distinguished from chromosomal genotypes by ing the leuC6 mutation"). enclosure in square brackets. Whenever applica- ble, employ the above rules for designating non- Bacteriophages. In most cases, viruses have Mendelian genes. It is advisable to avoid the use no phenotype, since they have no metabolism of Greek letters but to use instead their translit- outside host cells. Therefore, distinctions be- eration (e.g., [rho+], [rho-], [psi+], and [psi-]). tween a phenotype and genotype are not made. For the current linkage map of S. cerevisiae Superscripts are employed to indicate hybrid consult Mortimer and Schild, Microbiol. Rev. genomes. Genetic symbols may be one, two, or 44:519-571, 1980. three letters. For example, a mutant strain of lambda may be designated as X cI857 int2 redl 14 "Mutant" vs. "mutation." Keep in mind the Aaml 1; this strain carries mutations in genes cI, distinction between a mutation (an alteration of int, and red and an amber-suppressible (am) the primary sequence of the genetic material) mutation in gene A. Host DNA insertions into and a mutant (a strain carrying one or more viruses should be delineated by square brackets, mutations). One may speak about the mapping and the genetic symbols and designations for of a mutation, but one cannot map a mutant. INSTRUCTIONS TO AUTHORS .ii Likewise, a mutant has no genetic locus-only a It is often possible to use pronouns or to phenotype. paraphrase a long word after its first use (e.g., Strain designations. Avoid the use of a geno- "the drug," "the substrate"). Standard chemi- type as a name (e.g., "spe40-2 was used for cal symbols, numerical multiples (e.g., Me2SO ..."). If a strain designation has not been for dimethyl sulfoxide), and trivial names or chosen, select an appropriate word combination their symbols (folate, Ala, Leu, etc.) may be (e.g., ". . . either strain AN33 or another strain used for terms that appear in full in the neighbor- containing the spe40-2 mutation . . ing text. .'). In addition to abbreviations for standard units Transposable elements, plasmids, and restric- of measurement and chemical symbols of the tion enzymes. Nomenclature of transposable ele- elements, the following should be used without ments (insertion sequences, transposons, phage definition in the title, abstract, text, figure leg- Mu, etc.) should follow the recommendations of ends, and tables: DNA (deoxyribonucleic acid); Campbell et al. (Gene 5:197-206, 1979), with the cDNA (complementary DNA); RNA (ribonucle- modifications referred to in the instructions to ic acid); RNase (ribonuclease); DNase (deoxyri- authors in the Journal of Bacteriology. The bonuclease); rRNA (ribosomal RNA); mRNA system of designating transposon insertions at (messenger RNA); tRNA (transfer RNA); AMP, sites where there are no known loci, e.g., zef- ADP, ATP, dAMP, GTP, etc. (for the respective 123::TnS, has been described by Chumley et al. 5' phosphates of adenosine or other nucleo- (Genetics 91:639-655, 1979). Use the nomencla- sides); 2'-AMP, 3'-AMP, and 5'-AMP (the 2'-, ture recommendations of Novick et al. (Bacteri- 3'-, and 5'-, when needed for contrast, phos- ol. Rev. 40:168-189, 1976) for plasmids and phates of the nucleosides); NAD+ (nicotinamide plasmid-specified activities, of Low (Bacteriol. adenine dinucleotide, oxidized); NADH (nico- Rev. 36:587-607, 1972) for F-prime factors, and tinamide adenine dinucleotide, reduced); NADP of Roberts (Nucleic Acids Res. 9:r75-r96, 1981) (nicotinamide adenine dinucleotide phosphate); for restriction enzymes and DNA fragments NADPH (nicotinamide adenine dinucleotide derived from treatment with these enzymes. phosphate, reduced); Pi (orthophosphate); PP, Recombinant DNA molecules constructed in (pyrophosphate); UV (ultraviolet); PFU vitro follow the nomenclature for insertions in (plaque-forming units); CFU (colony-forming general. DNA inserted into recombinant DNA units); Tris [tris(hydroxymethyl)aminometh- molecules should be described, using the gene ane]; DEAE (diethylaminoethyl); and EDTA symbols and conventions for the organism from (ethylenediaminetetraacetate). Abbreviations which the DNA was obtained. for cell lines (e.g., HeLa cells) also need not be defined. ABBREVIATIONS AND CONVENTIONS The following abbreviations should be used Verb Tense without definition in tables: amt (amount) SE (standard error) Use the past tense in referring to results approx (approximately) SEM (standard error of the recorded in the present paper. Use the present avg (average) mean) tense in discussing previously established find- concn (concentration) sp act (specific activity) ings and generally accepted phenomena. diam (diameter) sp gr (specific gravity) expt (experiment) temp (temperature) Abbreviations ht (height) tr (trace) It is strongly recommended that all mo (month) vol (volume) abbrevia- mol wt (molecular weight) vs (versus) tions except those listed below be introduced in no. (number) wk (week) the first paragraph in Materials and Methods. prepn (preparation) wt (weight) Alternatively, define each abbreviation and in- SD (standard deviation) yr (year) troduce it in parentheses the first time it is used; e.g., "cultures were grown in Eagle minimal Reporting Numerical Data essential medium (MEM)." Generally, eliminate Standard metric units are used for reporting abbreviations that are not used at least five times length, weight, and volume. For these units and in the text (including tables and figure legends). for molarity, use the prefixes m, I, n, and p (for Abbreviations should be used primarily as an aid 10-3, 10-6, 10-9, 10-12, respectively). Likewise, to the reader, rather than as a convenience for use the prefix k (for 103). Avoid compound the author, and therefore their use should be prefixes such as mp. or RR,. Use ,g/ml or ,ug/g in limited. Abbreviations other than those recom- place of the ambiguous ppm. Units of tempera- mended by the IUPAC-IUB (Biochemical No- ture are presented as follows: 37°C or 324 K. menclature and Related Documents, 1978) When fractions are used to express units such should be used only when a case can be made for as enzymatic activities, it is preferable to use necessity, such as in tables and figures. whole units, such as "g" or "min," in the viii INSTRUCTIONS TO AUTHORS denominator instead of fractional or multiple when the isotopic symbol is attached to a word units such as ,ug or 10 min. For example, "pmol/ that is not a specific chemical name (e.g., 131I- min" would be preferable to "pmol/10 min," labeled protein, '4C-amino acids, 3H-ligands, and ",umol/g" would be preferable to "nmol/ etc.). ,ug." For specific chemicals, the symbol for the It is also preferable that an unambiguous form isotope introduced is placed in square brackets such as the exponential notation be used in place directly preceding the part of the name that of multiple slashes; for example, ",umol g-' describes the labeled entity. Note that config- min-"' is preferable to ",Lmol/g per min." uration symbols and modifiers precede the iso- See the CBE Style Manual, 4th edition, for topic symbol. The following examples illustrate more detailed information regarding the report- correct usage: ing of numbers. Also contained in this source is ["4Clurea UDP-[U-'4CJglucose information on SI units to be used for the L-[methyl-'4Clmethionine E. coli [32PIDNA reporting of illumination, energy, frequency, [2,3-3Hlserine fructose 1,6-[ 1-32P]bis- pressure, and other physical terms. Always re- [c-'4C]Iysine phosphate port numerical data in the appropriate SI unit. [Y-32PIATP This journal follows the same conventions for Labeled Isotopically Compounds isotopic labeling as the Journal of Biological For simple molecules, isotopic labeling is indi- Chemistry, and more detailed information can cated in the chemical formula (e.g., 14CO2, be found in the instructions to authors of that 3H20, H235SO4). Brackets are not employed journal (first issue of each year). 1983 Full Membership American Society for Microbiology 1913 I St., NW, Washington, DC 20006

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