Isolation and characterization of cDNA clones for the mouse thymocyte B cell antigen (ThB).
The Thb locus is responsible for the expression of 15-kDa phosphatidyl inositol anchored molecules (ThB) on murine thymocytes and B cells. Thb expression as detected with mAb is polymorphic on B cells with two alleles, Thbh and Thb1 responsible for the high and low expression of ThB on B cells. The regulatory locus for Thb expression had been mapped with the Ly-6 cluster of genes to Chr 15. In our study we used expression cloning in COS cells to isolate cDNA clones that code for ThB after transfection; the cDNA products react with anti- ThB antibodies, but not with Ly-6A.2, -6B.2, -6C.2, or -6D.2 antibodies. One of these clones, pThB-A contains insert of 702 bases which was sequenced. The translated amino acid sequence has 11 cysteine residues, and together with the absence of potential N-linked glycosylation sites is similar to the structure of the Ly-6 molecules. The nucleotide and amino acid sequences of ThB cDNA were compared to those of Ly-6 genes and the Ly-6 related human CD59 and show clear homology. Finally using interspecies crosses, the structural Thb gene has been mapped to Chr 15; thus both structural and regulatory genes map to a similar site. The genetic map location near Ly-6 and the sequence similarity suggest that Thb and Ly-6 may have been derived from the same progenitor by gene duplication.
Gumley
T P
TP
Austin Research Institute, Austin Hospital, Heidelberg, Victoria, Australia.
McKenzie
I F
IF
Kozak
C A
CA
Sandrin
M S
MS
D000595:Amino Acid Sequence; D000818:Animals; D000950:Antigens, Ly / Q000235:genetics; D000954:Antigens, Surface / Q000235:genetics*; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002874:Chromosome Mapping; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification*; D051379:Mice; D008969:Molecular Sequence Data
D000950:Antigens, Ly; D000954:Antigens, Surface; D004247:DNA