Walker I D, Glew M D, O'Keeffe M A, Metcalfe S A, Clevers H C, Wijngaard P L, Adams T E, Hein W R
Department of Veterinary Science, University of Melbourne, Parkville, Victoria, Australia.
Immunology. 1994 Dec;83(4):517-23.
The WC1 protein is a cell surface constituent of bovine gamma delta T cells and is absent from most or all CD4+, CD8+ T cells and from B cells. It is a single polypeptide chain of 1413 amino acids consisting of 11 non-identical repeats of a 110 amino acid consensus sequence, homologous to the macrophage scavenger receptor cysteine rich (SRCR) domain. A 1059 nucleotide segment of the bovine WC1 cDNA sequence was used as a probe to molecularly clone homologous DNA segments from a sheep genomic library in which the presence of numerous positive plaques was documented. The high representation of such recombinants (1-2/1000 clones) within the library suggested the existence of multiple genes for WC1 (called T19 in sheep) and supported Southern blotting data which revealed an unexpectedly high number of WC1/T19 restriction fragments in sheep genomic DNA. Restriction digests of 27 samples of T19 genomic recombinants were examined by electrophoresis and Southern blotting. All but two pairs of recombinants exhibited non-overlapping restriction digest patterns. Four recombinant DNA samples were partially sequenced and in all cases putative exons were identified and exhibited high homology to appropriate segments of the WC1 cDNA at the levels of both nucleotide and amino acid sequence. Furthermore, multiple nucleotide and amino acid differences occurred between all sequences compared, establishing the existence of a repertoire of non-identical T19 genes, each with the potential to encode a different protein.
WC1蛋白是牛γδT细胞的一种细胞表面成分，在大多数或所有CD4⁺、CD8⁺T细胞以及B细胞中不存在。它是一条由1413个氨基酸组成的单多肽链，由11个110个氨基酸的共有序列的非同一重复序列组成，与巨噬细胞清道夫受体富含半胱氨酸（SRCR）结构域同源。牛WC1 cDNA序列的一个1059核苷酸片段被用作探针，从一个绵羊基因组文库中分子克隆同源DNA片段，其中记录到存在大量阳性噬菌斑。文库中此类重组体的高比例（1 - 2/1000个克隆）表明存在多个WC1基因（在绵羊中称为T19），并支持了Southern印迹数据，该数据显示绵羊基因组DNA中WC1/T19限制性片段的数量出乎意料地高。通过电泳和Southern印迹检查了27个T19基因组重组体样本的限制性酶切。除了两对重组体之外，所有重组体都表现出不重叠的限制性酶切模式。对四个重组DNA样本进行了部分测序，在所有情况下都鉴定出了推定的外显子，并且在核苷酸和氨基酸序列水平上与WC1 cDNA的相应片段表现出高度同源性。此外，所有比较的序列之间都存在多个核苷酸和氨基酸差异，这表明存在一系列不同的T19基因，每个基因都有可能编码一种不同蛋白质。
