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H-I, Atenth Allele at the Histocompatibility-2 Locus In

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H-I, Atenth Allele at the Histocompatibility-2 Locus In H-i, a Tenth Allele at the Histocompatibility-2 Locus in the Mouse as Determined by Tumor Transplantation* SALLY LYMAN ALLENt (Roscoe B. Jackson Memorial Laboratory, Bar Harbor, Maine, and Departmeni of Zoology, Universiiy of Chicago, CMcago, Ill.) By crosses involving the A strain, Gorer demon rying H-Pp and H-p, but further genetic tests, on strated the existence of a histocompatibility gene the basis of reaction to transplantation, indicated which determines the presence of antigen II, found that the antigens produced by these alleles were in A strain erythrocytes as well as in other normal slightly different in nature. tissues and in tumors from this strain (5, 6). The The H-f@?locusis complicated by the presence of locus was later designated H4? (8). Thus, it is now composite alleles. Originally, the type allele char known that an allele at this locus not only deter acteristic of the A strain was designated simply mines the presence of a particular antigen or anti [email protected],by genetic crosses, it was found that gens, but, as a consequence, susceptibility or re animals of the heterozygous genotype H-@'/H-P@, sistance to certain transplantable tumors. irrespective of the strain from which the alleles The close linkage of H-@ with the gene for fused H-fi' and H@PJccame,grew strain A tumors (18, tail (Fu), producing distortion and fusion of tail 18). Mice bearing other alleles in various combina vertebrae, was found by Gorer, Lyman, and Snell tions did not grow strain A tumors. On the basis (8). Later, its linkage with two other loci on this of this evidence the type allele found in the A chromosome (IX), Ki and T, was reported (14). strain was presumed to be in some sense compound Kinky tail (Ki or Fu'@) is phenotypically similar and was redesignated H-@. That it actually de to fused tail (2., 11) and may be an allele of Fu (4). termines two antigens or two antigenic factors, D Brachyury (T) typically produces a shortened tail and IC, has been shown by Gorer and Mikulska (9) (3). All three or four of these loci are located close and becker, Counce, and Smith (10). It has not together on the ninth chromosome of the mouse in been determined whether two or more closely the order H-@ Fu (Ki) T (1). linked loci may be involved rather than a single The linkage of H-@ with these loci has been used locus with components. to identify new alleles at the H-@ locus and to de As is the case with the alleles determining the termine their distribution in 2.1inbred strains (18). M-N blood groups in man, each H-@ allele exerts Through extensive tests seven alleles and two sub an effect in the heterozygote. Furthermore, these group alleles have been found at locus H-i? (12., 18, alleles probably produce antigens of considerable 15, 16, 18). By far the greatest number of strains strength, since in many crosses the ratio of sus carry the alleles H-@, H-p, and H-p. The other ceptible to resistant animals reveals only the pres alleles (H-p, H-2―,H-Prn?―,andH-s) have so far ence of H-@t?,whereas earlier results with other tu been found in only one strain each. The two sub mors pointed to a multiplicity of histocompatibili group alleles are H-2―and H-p'. The strains con ty loci. Apparently, the H-fe alleles determine anti taining these alleles originally were classed as car gens which may “crowdout―antigens of weaker strength produced by other histocompatibility S This investigation has been aided by a John M. Prather research fellowship from the University of Chicago and by a genes (7). However, some crosses do show other 2-year, 8-month predoctoral fellowship from the National loci segregating. Cancer Institute. Inbred mice and animal cages were provided Two other histocompatibility loci have been by,the Roscoe B. @1acksonMemorialLaboratory with the specifically identified. H-i is located on the first financial assistance of a grant-in-aid (EG-14) from the Amen can Cancer Society on recommendation of the Committee on chromosome in mice, crossing over with albinism Growth of the National Research Council. (c) being in the neighborhood of 2.0-2.5per cent t Present address: Department of Zoology,University of (17). H-,@ has been found closely linked with the Michigan, Ann Arbor, Mich. agouti locus.' Tentatively, it appears that these Received for publication January 27, 1965. 1 Dr. George D. Snail, personal communication. 815 Downloaded from cancerres.aacrjournals.org on October 2, 2021. © 1955 American Association for Cancer Research. 316 Cancer Research loci determine antigens “weaker―ineffect than if they survived a small tumor which grew and H43. then regressed. The CA stock of mice is a “multipledominant― Here, M and A were known previously to carry stock of the genotype AA CaCa Fufu Ww de different H-2 alleles; therefore, (a) if linkage be signed for use in linkage tests. It was the stock tween H-fl and Fu is manifest, M and F' carry dif originally employed in establishing the H-2 locus ferent alleles; (b) if no linkage is manifest, it may in which Fu was found linked to “h-s,―agene for be presumed that M and F' carry the same allele, “resistance―to A-strain tumors. The H-L@allele although more extensive testing is necessary to present in this stock was introduced into strain A prove this conclusion beyond doubt. (genotype H-P@/H-P@) by successive backcrosses u@ing Fu as a chromosome marker. A line of the A RESULTS strain, which we may call F'@,was thus developed A summary of the results may be found in Table having the genotype H-9Fu/H-Pflu. Since the 1. In the first column are listed the crosses, fol Fh stock was to be used in setting up crosses de lowed by columns indicating the tumor inoculated, signed to determine the order of the loci Fu, T, and the results of tumor inoculation, the allelic group H-@ (1) it was of interest to identify the allele in under test, and the conclusions which may be this stock. Therefore, appropriate tests were set up drawn from the data. The statistic used in testing to determine if H-9 was an allele already estab for linkage of H43 with Fu was: lished or a new allele at the H-@ locus. .5—r 1=S.E. (q@—q@) MATERIALS AND METHODS The cross used in testing for new alleles at the where r = recombination value which is found by H-9@locus,described by Snell, Smith, and Gabriel combining the second and third classes. In every son (17), has the following form: (M X T) X N, cross except Case 15 linkage was found, and in this where M and N are any two inbred strains and T case there were too few positive animals. The con is one of the stocks carrying T, Fu, or Ki. Offspring elusion may be drawn that H-I?' is another new of the first cross which display the particular tail allele at the H-@ locus. anomaly segregating are chosen for crossing to N. Cases 3 and 9 were crosses set up to test whether Then, the offspring of the double cross are inocu H-il' produces either the D or I( antigenic factors. lated with a tumor native to the strain in the M An A-strain tumor was used in these cases. The position. Generally, the occurrence of linkage fact that linkage was manifest shows that H-9 proves that strains T and N carry an H-@ allele (or does not produce either D or K. Consequently, alleles) different from that in strain M. On the H-fY does not belong to either the H4―,H-9, or other hand, the absence of linkage establishes a H-@, H-P.?―groups. presumption but does not prove beyond question Analysis of the data contained in Table 1 re that strains M and T and/or M and N carry the vealed further information. One point of interest same H-@ allele. was the occurrence of ratios indicating the segre In the present crosses the F' stock was used in gation of the H-i locus in addition to H-i. It was the T position. All M X Fh mice resulting from the evident that in some of the crosses more than one first cross were initially checked to make sure that histocompatibility gene was segregating, since the a crossover had not arisen (H-@Fu), by mating number of negative animals observed was far more to a third strain, other than strain A, and by the than the theoretical 50 per cent expected for one inoculation of the offspring with A-strain tumor factor. In some of the crosses albinism (c) was in 15091a. Fu mice would all succumb to the tumor eluded, and, since H-i had been found by Snell and if crossing over had occurred; otherwise, all mice ICelton (17) to be linked with albinism, it was pos would be expected to be “negative―tothe tumor. sible to determine if the increase in negative ani Then, the M X F'@mice known to be noncross mals in these cases was due to the additional seg overs were crossed to N. In most cases the A strain regation of the H-i locus. was used in the N position. Thus, the test cross Three of the crosses, Cases 4, 8, and 12., were could be rewritten: (M X F') X A.
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