Extension of the H-2 TLb molecular map. Isolation and characterization of T13, T14, and T15 from the C57BL/6 mouse.
A region of the TLb locus encompassing T11 to T13 contains retroviral sequences TLev1 and TLev2. As part of a study to determine whether the retroviral elements are involved in the expression of TL genes, the genomic organization of this region was reexamined in greater detail. A result of these investigations is the extension of the H-2 TLb molecular map. Two additional TL genes have been isolated from C57BL/6 mice, T14 and T15. The genomic organization of T9 through T15 is presented. The nucleotide sequence has been determined for exons 4, 5, and 6 of T13. As a result of a C to T conversion, a termination codon is introduced into exon 4, indicating that T13 either encodes a secreted protein or is a pseudogene. T13 was found to be more homologous to the H-2 genes outside the TL region. T14 has been physically disrupted by the integration of TLev1, and the H-2 sequences appear to have diverged greatly. The relationship of the TL regions of the b and c haplotypes has been investigated using numerous low copy probes. The genome of BALB/c (TLc) is shown to lack a counterpart of the T13-T15b region. Homologous regions exist in the two haplotypes; yet considerable polymorphism is observed. TLb mice do not express TLa on the cell surface of normal thymocytes while TLc mice do; TLa expression is activated in many TLb leukemias. The diversity seen in the T13-T15 region may provide insights into the phenotypic expression or regulatory mechanisms of TL expression in these two haplotypes.
Brown
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GD
Department of Pathology, New York University Medical Center, NY 10016.
Choi
Y
Y
Egan
G
G
Meruelo
D
D
D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics*; D001483:Base Sequence; D004273:DNA, Neoplasm / Q000032:analysis; D005786:Gene Expression Regulation; D005805:Genes, MHC Class I; D005814:Genes, Viral; D009052:Leukemia Virus, Murine / Q000235:genetics*; D007942:Leukemia, Experimental / Q000235:genetics; D008214:Lymphocytes / Q000032:analysis; D008562:Membrane Glycoproteins; D051379:Mice; D008810:Mice, Inbred C57BL / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012689:Sequence Homology, Nucleic Acid; D013945:Thymoma / Q000235:genetics; D013953:Thymus Neoplasms / Q000235:genetics
D000951:Antigens, Neoplasm; D004273:DNA, Neoplasm; D008562:Membrane Glycoproteins; C028388:thymus-leukemia antigens