The thymus leukemia (TL) antigens, encoded by class I genes in the Tla subregion of the major histocompatibility complex (MHC), are cell surface molecules expressed on thymocytes of certain strains of mice and on certain T-cell leukemias. In order to study the fine structure and interrelationships of genes of the Tla subregion, a Tla-specific probe was isolated from the TL-encoding T13(c) gene of BALB/c mice (Tla(c) haplotype). The probe hybridized with two Tla genes in the Tla(c) heplotype (T13(c) and T3(c)) and with only one in the Tla(b) haplotype (T3(b)). Examination of this subset of Tla genes (T3(b), T3(c), and T13(c)) by restriction enzyme analysis and oligonucleotide hybridization studies confirmed that T3(b) is the allele of T3(c) and that T3(c) and T13(c) may have arisen by duplication. The T3(b) gene, while not transcribed in the tissues of the TL- strain C57BL6, was shown to be transcriptionally active in the TL-expressing leukemic cell line ERLD derived from that strain. The T3(b) gene was cloned and its complete DNA sequence was determined. These data permit complete comparison of two Tla-region genes, T3(b) and its homologue T13(c), and allow us to conclude that these genes show extraordinarily high sequence conservation, in contrast to alleles of the H-2K- and H-2D-region genes. Comparison of T3(b) with other class I sequences in the H-2 and Qa subregions suggests that the T3-subset genes are the most divergent from other class I genes.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 1986|
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