STRUCTURE AND FUNCTION OF S-ANTIGEN AND ITS GENE

牛视网膜S抗原的互补DNA（cDNA）和基因已被克隆。 分离并表征。 cDNA克隆从Lambdagt11 用多克隆S抗原抗血清构建cDNA表达文库， 使用单克隆抗血清进一步验证。 观察到的最大cDNA为 500个碱基对长。 这随后被用于筛选cDNA克隆， 一个Lambdagt10视网膜文库，产生多达900个碱基对的片段， 长度 由500个碱基对的cDNA克隆合成的多肽， 被2种不同的单克隆抗体识别。 相反，多肽 由小于400个碱基对的cDNA克隆产生的仅被识别 一种单克隆抗体。 发现500个碱基对的S抗原cDNA 与mRNA特异性杂交（约1700 + 200个碱基对） 从牛视网膜和松果体制备，但不与来自肝脏的mRNA， 大脑皮层和小脑。 S抗原经高效液相色谱法高度纯化， 测定了近N端的多肽序列（19个氨基酸）。 的dna 使用双脱氧核苷酸测定了500和900个碱基对的cDNA序列。 法 900个碱基对的cDNA覆盖了来自 羧基末端 从DNA序列推断的多肽是相同的 与已知S-抗原肽序列相同。 S-抗原多肽（240 AA残基）在高产表达细菌系统中表达， 诱发实验动物的葡萄膜炎。 S抗原和视蛋白探针用于原位杂交分析。 S抗原和视蛋白mRNA仅在视杆细胞内节检测到， 松果体细胞而非视锥细胞。

Complementary DNA (cDNA) and gene for bovine retinal S-antigen have been isolated and characterized. cDNA clones were isolated from a Lambdagt11 cDNA expression library using polyclonal S-antigen antiserum and were further verified using monoclonal antisera. The largest cDNA observed was 500 base pairs long. This was used subsequently to screen cDNA clones from a Lambdagt10 retinal library, yielding fragments up to 900 base pairs in length. Polypeptides synthesized by the 500 base pair cDNA clone was recognized by 2 different monoclonal antibodies. In contrast, polypeptides produced by cDNA clones smaller than 400 base pairs were recognized by only one monoclonal antibody. The 500 base pair S-antigen cDNA was found to hybridize specifically to mRNA (approximately 1700 + 200 base pair) prepared from bovine retina and pineal gland but not to mRNA from liver, cerebral cortex and cerebellum. S-antigen was highly purified by HPLC and determined polypeptide sequence (19 AA) at near N-terminal. The DNA sequences of 500 and 900 base pair cDNA were determined using dideoxy method. 900 base pair cDNA covers the 240 amino acid residues from carboxyl terminal. The polypeptide deduced from DNA sequence is identical in sequence with known S-antigen peptides. The S-antigen polypeptide (240 AA residue) expressed in high yield expression bacterial system did not induce uveitis in the experimental animals. S-antigen and opsin probes were used for in situ hybridization analysis. S-antigen and opsin mRNAs were detected only rod cell inner segments and pinealocytes but not cone cells.