Abstract: |
Three Tla region-specific probes have been generated from the BALB/c genomic cosmid clone C6.3. One probe, pTL1, corresponds to 3' sequences of a thymus leukemia (TL)-encoding gene, whereas pTL2 and pTL3 detect noncoding flanking sequences. The TL specificity of pTL1 was demonstrated by studies of RNA from thymocytes of TL+ and TL- mouse strains and from TL+ and TL- leukemias; presence/absence of pTL1+ transcripts correlated with presence/absence of TL antigens detected serologically. Nine Tla haplotypes were defined by restriction fragment polymorphism with pTL1, and the number of TL genes has been estimated to be ≥4 in Tlaa, Tla(c) and Tlae mice, ≥3 in Tla(d) mice, and ≥2 in Tlab and Tla(f) mice. A TL-encoding gene (C25.1) from the C57BL/6TL+ leukemia ERLD has been cloned and sequenced, and the exon/intron organization of C25.1 has been deduced from the structure pTL+ cDNA clones and from the known organization of H-2 genes. The major structural differences between TL and H-2 genes are in exons coding for the cytoplasmic domain. |