ISSN:
1432-1211
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract We have determined the nucleotide sequence of Q8/9 d gene of the BALB/c strain of mice, isolated from Steinmetz's cosmid library. As for all other class I genes of the Qa region, the Q8/9 d gene spans approximately 4.7 kilobases (kb) and consists of seven exons and six introns. A seven bases deletion in exon 3 results in the occurrence of an early termination codon. Thus the Q8/9 d gene cannot encode a normal class I protein. Comparison of the nucleotide sequence of the Q8/9 d gene with that of other class I MHC genes revealed a stronger homology to Q7 and Q8 than to K, D, L, TL, and other Q genes. However, the gene cannot originate from a mere fusion between Q8 and Q9 genes except if the ancestor to putative Q8 d was markedly different from the present Q8 b gene. Using polymerase chain reaction (PCR) technology, we have confirmed the presence of a Q8/9 gene, identical to that present in cosmid 46.1, in the genome of BALB/cJ (Qa-2low). Finally, it has been reported that cDNA clone 94-A, which codes for a Qa-2 antigen, could derive from a transcript of gene Q8/9 d. The nucleotide sequences of gene Q8/9 d and of cDNA clone 94-A are distinctly different in their 5′ regions, in spite of an almost perfect matching in their 3′ regions. Thus, clone 94-A cannot derive from an mRNA transcribed from the Q8/9 d gene.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00230499
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