Tissue-specific expression of cell-surface Qa-2 antigen from a transfected Q7b gene of C57BL/10 mice.
We screened a cDNA library prepared from a BALB.B10 CTL clone that expresses Qa-2 antigen, and isolated four clones derived from Q7b, a Qa region gene of C57BL/10. One of these Q7b cDNAs and the Q7b chromosomal gene were subcloned into expression vectors and transfected into L cells and R1.1 thymoma cells. We found that the chromosomal Q7b gene expresses Qa-2 on the surface of R1.1 cells, but not on L cells while the Q7b cDNA expresses protein on the surface of both cell types. The levels of Qa-2 expression do not correlate with the total levels of Q7b mRNA in these transfectants. Our results suggest that the tissue-specific expression of Qa-2 may be controlled, in part, by mechanisms of alternate RNA splicing. By using hybrid gene constructs, we have mapped the tissue-specific element to the 3' part of the gene, downstream of a site near the middle of exon 4. The hybrid polypeptides differ significantly in their transmembrane and cytoplasmic regions. These portions of the protein also may play a role in the tissue-specific expression of Qa-2.
D000818:Animals; D000954:Antigens, Surface / Q000235:genetics*; D001483:Base Sequence; D002874:Chromosome Mapping; D003101:Collodion; D004247:DNA / Q000032:analysis / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005091:Exons; D015395:Histocompatibility Antigens Class I; D006824:Hybridization, Genetic; D051379:Mice; D008815:Mice, Inbred Strains; D010209:Paper; D014162:Transfection
D000954:Antigens, Surface; D015395:Histocompatibility Antigens Class I; C032907:Q surface antigens; D003101:Collodion; D004247:DNA