Genomic constitution of an H-2:Tla variant leukemia.
A TL+ leukemia of a (B6 X A)F1 hybrid mouse (H-2b/H-2a) was previously subjected to immunoselection against H-2a by passage in (B6 X A.SW)F1 mice (H-2b/H-2s). A variant leukemia line was obtained that serologically lacked not only the H-2a phenotype but also the TL phenotype determined by the linked cis Tlaa allele of strain A. The H-2b phenotype and the TL phenotype of the Tlab allele of the B6 strain, which is expressed only by leukemia cells, were retained by the variant. Southern blotting with an H-2 cDNA probe that identifies restriction fragment polymorphisms distinguishing alleles of the H-2 and Tla regions of the B6 and A strains indicates that both the H-2a and Tlaa alleles are missing from the genome of this H-2a:Tlaa negative variant. Since the variant has two apparently unaltered chromosomes 17, where the H-2:Tla complex is situated, and since the intensity of bands in Southern blotting is suggestive of H-2b homozygosity, it is considered that loss of the H-2a:Tlaa haplotype by the variant was accompanied by duplication of the H-2b:Tlab haplotype. The implied change from heterozygosity to homozygosity that the variant has undergone with respect to H-2:Tla was not paralleled by a similar change at the three other loci tested, since the variant retained heterozygosity for Pep-3 (chromosome 1), Gpi-1 (chromosome 7), and Es-1 (chromosome 8).
D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics*; D002871:Chromosome Banding; D002872:Chromosome Deletion; D005796:Genes; D006183:H-2 Antigens / Q000235:genetics*; D007942:Leukemia, Experimental / Q000235:genetics* / Q000276:immunology; D008562:Membrane Glycoproteins; D051379:Mice
D000951:Antigens, Neoplasm; D006183:H-2 Antigens; D008562:Membrane Glycoproteins; C028388:thymus-leukemia antigens