MOLECULAR AND CELLULAR VOLUME 8 MAY 1988 NUMBER 5

Aaron J. Shatkin, Editor in Chief(1990) Randy W. Schekman, Editor Joan A. Steitz, Editor (1990) Center for Advanced (1992) Yale University Biotechnology and Medicine University of California New Haven, Conn. Piscataway, N.J. Berkeley Robert Tjian, Editor (1991) David J. L. Luck, Editor (1992) Louis Siminovitch, Editor (1990) University of California Mount Sinai Hospital Berkeley New York, N.Y. Toronto, Canada Harold E. Varmus, Editor (1989) Steven L. McKnight, Editor (1992) University of California Carnegie Institution of Washington San Francisco Baltimore, Md. EDITORIAL BOARD Frederick W. Alt (1990) Michael Green (1988) Douglas Lowy (1990) Matthew P. Scott (1989) Susan Berget (1990) Jack F. Greenblatt (1988) Paul T. Magee (1988) Fred Sherman (1988) Arnold J. Berk (1988) Leonard P. Guarente (1988) James Manley (1989) Arthur Skoultchi (1988) Alan Bernstein (1990) Christine Guthrie (1989) Janet E. Mertz (1990) Barbara Sollner-Webb (1989) Barbara K. Birshtein (1990) James E. Haber (1990) Robert L. Metzenberg (1988) Frank Solomon (1988) J. Michael Bishop (1990) Hidesaburo Hanafusa (1989) Robert K. Mortimer (1988) Karen Sprague (1989) Michael R. Botchan (1990) Leland D. Hartwell (1990) Bernardo Nadal-Ginard (1990) Pamela Stanley (1988) (1990) Ari Helenius (1990) Paul Neiman (1989) Nat Sternberg (1989) Bruce P. Brandhorst (1990) (1990) Joseph R. Nevins (1990) Bruce Stiliman (1988) James R. Broach (1988) James B. Hicks (1989) Carol Newlon (1988) Kevin Struhl (1989) Joan Brugge (1988) Alan Hinnebusch (1988) Mary Ann Osley (1990) Bill Sugden (1988) Mario R. Capecchi (1990) Michael J. Holland (1990) Brad Ozanne (1989) Lawrence H. Thompson (1988) John A. Carbon (1990) Greg Hollis (1990) Harvey L. Ozer (1988) Shirley M. Tilghman (1990) Marian Carlson (1989) Anita K. Hopper (1988) Mary Lou Pardue (1988) Geoffrey Wahl (1989) C. Thomas Caskey (1990) Peter M. Howley (1988) Ira H. Pastan (1988) (1990) Lawrence A. Chasin (1988) Tony Hunter (1989) David Patterson (1988) Jonathan R. Warner (1990) Nam-Hai Chua (1988) Larry Kedes (1988) Gianni Piperno (1988) Alan M. Weiner (1990) Don W. Cleveland (1990) Robert S. Kerbel (1988) John R. Pringle (1988) Harold Weintraub (1988) Nicholas Cowan (1990) Daniel Klessig (1989) Jean-Paul Revel (1988) Reed B. Wickner (1988) Elizabeth A. Craig (1988) Barbara Knowles (1989) Daniel B. Rifkin (1988) Fred Winston (1988) James E. Darnell, Jr. (1988) Marilyn Kozak (1988) G. S. Roeder (1988) Owen Witte (1988) Mark Davis (1990) Monty Krieger (1989) Robert G. Roeder (1988) Elton T. Young (1990) Gideon Dreyfuss (1990) Elizabeth Lacy (1990) Naomi E. Rosenberg (1988) Michael Young (1988) Mary P. Edmonds (1990) Alan Lambowitz (1990) Rodney Rothstein (1990) Edward Ziff (1988) Thomas D. Fox (1990) Arthur D. Levinson (1990) Norman P. Salzman (1988) Mary-Jane Gething (1990) Susan Lindquist (1990) Paul Schedl (1990) Steve Goff (1989) Stuart M. Linn (1989) Milton J. Schlesinger (1989) Helen R. Whiteley, Chairman, Publications Board Kirk Jensen, Director of Publications Linda M. Illig, Managing Editor, Journals Linda M. Illig, Production Editor Molecular and Cellular Biology (ISSN 0270-7306) is devoted to the advancement and dissemination offundamental knowledge concerning the 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 Department. The journal is published monthly, one volume per year. The nonmember subscription price is $340 per year; single copies are $30. The member subscription price is $43 (foreign, $63 [air drop shipping]) per year; single copies are $8. 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 Publications Department, 1913 I St., N.W., 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 offailure 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., N.W., Washington, DC 20006. Made in the United States of America. Copyright C) 1988, American Society for Microbiology. a*: f A&N L ±I Pt{UA '1 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 arti- cle 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

Adams, David E., 2052 Eckhardt, Laurel A., 1932 MacDonald, Barbara, 2159 Schneider, William P., 2211 Allison, Daniel S., 1915 Emr, Scott D., 2105 Macdonald-Bravo, Heather, Schreurs, Jolanda, 2214 Almendral, Jose M., 2140 2140 Seebeck, Thomas, 2166 Andrisani, Ourania M., 1947 Fahl, William E., 2089 Magun, Bruce E., 2247 Sehgal, Amita, 2242 Frederick M., 1985 Feinbaum, Rhonda L., 1985 Manoharan, T. Herbert, 2089 Shapiro, Robert A., 1957 Ausubel, Sittisombut, Nopporn, 2034 Ayer, Donald E., 2021 Field, Jeffrey, 2159 Manrow, Richard E., 1957 Skoultchi, Arthur I., 1887 Filipowicz, Witold, 2042 Martis, Missie Jo, 1979 Smith, Patricia P., 1863 Balakier, Hanna, 2082 Fisher, Paul A., 1877 Marzluff, William F., 1887 Snyder, Michael, 2184 Banta, Lois M., 2105 Fujiwara, Jun, 2097 McDougall, James K., 1863 Sommer, Doris, 2140 Barta, Andrea, 2011 Fusco, Alfredo, 2261 Menninger, Joan C., 1863 Squire, Jeremy, 2082 Bateman, Erik, 1940 Miyajima, Atsushi, 2214 Stefano, James E., 2052 Becker, Andrew, 2082 Gallie, Brenda L., 2082 Morita, Elaine A.-, 1979 Steinert, Maurice, 2166 Bellot, F., 1970 Gasson, Judith C., 1979 Morla, Alex O., 2214 Stevens, Audrey, 2005 Bemis, Lynne T., 2125 Gentry, Larry E., 2229 Muldoon, Leslie L., 2247 Stevens, Craig W., 2089 Ben Amar, Mohamed F., 2166 Gettner, Sonya N., 2224 Stillman, Bruce W., 1923 Benton, Bret M., 1877 Givol, D., 1970 Nikawa, Jun-ichi, 2159 Stuart, S., 2149 Berlingieri, Maria Teresa, Goddard, Audrey D., 2082 Niman, Henry, 2251 Swanson, Maurice S., 2237 2261 Goldfinger, Naomi, 2078 Nimer, Stephen D., 1979 Berrios, Soledad, 1877 Nishimori, Katsuhiko, 2097 Tebabi, Patricia, 2166 Grieco, Michele, 2261 Thireos, George, 2132 Blanton, Harriet M., 2257 Guerrero, Isabel, 2233 Blinder, Dmitry, 1957 Oishi, Michio, 2097 Tsai, Ming-Jer, 2070 Tsai, Sophia Y., 2070 Blumberg, Hal, 1868 Hane, Bernhard G., 2089 Orbach, Marc J., 2211 Bravo, Rodrigo, 2140 Hartmuth, Klaus, 2011 Ullrich, A., 1970 Broek, Daniel, 2159 Hartshorne, Toinette A., 1868 Paigen, Kenneth, 2117 Brondyk, William H., 2089 Paule, Marvin R., 1940 Hatton, K. S., 2149 van de Putte, Pieter, 2195, Brown, E. H., 2149 2132 Pays, Annette, 2166 Brunner, Amy M., 2229 Hauge, Brian M., Pays, Etienne, 2166 2204 Burckhardt, Jean, 2140 Heintz, Nicholas H., 1923 Pellicer, Angel, 2233 van Muijen, Goos N. P., 2204 Burgess, Jeffrey A., 2089 Hensold, Jack O., 2219 Perera, Julian, 2140 van Pelt-Heerschap, Hilde, Herrero, Juan-Jose, 2042 Phillips, Robert A., 2082 2204 Campbell, Bruce A., 1993 Herrick, David, 1957 Pohl, Jens, 2078 Velcich, Anna, 2177 Canton, Marc, 2082 Housman, David E., 2219 Portella, Giuseppe, 2261 Vennstrom, B., 1970 Howk, R., 1970 Verma, Inder M., 2251 Chandler, Susan H., 1863 Pot, David A., 1947 Villarreal, Luis P., 1993 Chao, Moses V., 2242 Huang, Der-Hwa, 1906 Purchio, A. F., 2229 Hwung, Young-Ping, 2070 Cohen, Donna R., 2063 Wachsman, William, 1979 Cooper, Jonathan A., 2229 Radler-Pohl, Adriana, 2078 Iqbal, M. A., 2149 Wall, Doris A., 2242 Crowe, David T., 2070 Raymond, Vincent, 2251 Wang, Jean Y. J., 2214 Curran, Tom, 2063 Resh, Marilyn D., 1896 1957 Wang, Lee-Ho, 2070 Jacobson, Allan, Reyes, Evangelica, 2082 Watson, Gordon, 2117 Davis, Ronald W., 2184 Johnson, A., 1970 Rodgers, Linda, 2159 Wiebauer, Karin, 2042 Denis, Clyde L., 2125 Rodland, Karin D., 2247 Wigler, Michael, 2159 Dero, Brigitte, 2166 Kartasova, Tonja, 2195, 2204 Roeder, Robert G., 1906 Wilson, Ian A., 2159 De Togni, Pietro, 2251 Klionsky, Daniel J., 2105 Rotter, Varda, 2078 Winkler, M., 1970 Dhar, V., 2149 Kohda, Takashi, 2097 Roussou, Irene, 2132 Diamond, Lisa E., 2233 Yanofsky, Charles, 2211 Didamo, V. T., 2149 Lacy, Elizabeth, 2224 Santoro, Massimo, 2261 Young, Elton T., 1868, 1915 Dinh, Thanh-Hoai, 2247 Lax, I., 1970 Sap, J., 1970 Yu, Hua, 1932 Dixon, Jack E., 1947 Lerner, Richard A., 2159 Sapolsky, Ronald J., 2184 Dreyfuss, Gideon, 2237 Levine, B. Jane, 1887 Sawchenko, Paul, 2251 Zakian, Virginia A., 2257 Dunn, James, 2082 Littman, Dan R., 2224 Schildkraut, C. L., 2149 Zaller, Dennis M., 1932 Durnam, Diane M., 1863 Liu, Ta-Jen, 1887 Schirrmacher, Volker, 2078 Zhu, Zheng, 1947 Dynan, William S., 2021 Lonberg, Nils, 2224 Schlessinger, J., 1970 Ziff, Edward, 2177 When the focus is on basic microbial research, _~~~ readers turn to the following ASMjournals: -Om Molecular and Cellular Biology IIS EDITOR IN CHIEF: Aaron J. Shatkin MCB is devoted to the advancement and dissemination of fundamental knowl-

Iwe edge concerning the molecular biology of eucaryotic cells. of both microbial and im higher organisms. The journal publishes papers on cellular morphology and function. genome organization. regulation of genetic expression. morphogen- esis. and somatic cell genetics. In addition. it contains articles concerning plas- mid vectors and virus-infected cells in which emphasis is clearly on the cell. Monthly. ISSN: 0270-7306. 4.900 pages in 1988. Nonmember Member (US) Member (Foreign) S340.00 $43.00 $63.00 Add $165.00 for foreign airmail service. Joumal of Bacteriology NI _S| EDITOR IN CHIEF: Samuel Kaplan The oldest of the ASM journals. JB is the leading periodical. worldwide. in its field. It is devoted to the advancement and dissemination of fundamental W 056_ knowledge concerning bacteria and other microorganisms. including fungi and other uniceilular. eucaryotic organisms. Regular features include articles on structure and function. plant microbiology, membranes. eucaryotic cells. genetics and molecular biology. plasmids and transposons. physiology and metabolism, and enzymology. Monthly. ISSN: 0021-9193. 5.700 pages in 1988. Nonmember Member (US) Member (Foreign.) $340.00 S41.00 $63.00 Add $210 00 for foreign airmail service.

_S Jounal of Virology EDITOR IN CHIEF: Arnold J. Levine S This leading research journal is devoted to the dissemination of fundamental knowledge concerning viruses of bacteria. plants. and animals. JVI publishes reports of original research in all areas of basic virology. including . biophysics. genetics. immunology, morphology. physiology. and pathogenesis and immunity. Monthly. ISSN: 0022-538X. 4.400 pages in 1988. Nonmember Member (US) Member (Foreign) S350.00 $41.00 $63.00 Add S1 70.00 for foreign airmail service.

Infection and Immunity EDITOR IN CHIEF. Joseph W. Shands, Jr.

IAI publishes articles on: infections caused by pathogenic bacteria. fungi. and parasites: ecology and epidemiology of pathogenic microbes: virulence factors. such as toxins and microbial surface structures: nonspecific factors in host resistance and susceptibility to infection: and immunology of %I I so microbial infection. Oral microbiology is given extensive coverage. Monthly. ISSN: 0019-9567. 3.700 pages in 1988. Nonmember Member (US) Member (Foreign) $340 00 S41.00 $6300 Add $140 00 for foreign airmail service. 1