Walter G, Ferre F, Espiritu O, Carbone-Wiley A
Department of Pathology, University of California at San Diego, La Jolla 92093.
Proc Natl Acad Sci U S A. 1989 Nov;86(22):8669-72. doi: 10.1073/pnas.86.22.8669.
Polyoma virus medium tumor antigen forms specific complexes with several cellular proteins; among these is a protein of approximately 61 kDa. With antibodies directed against medium tumor antigen, the 61-kDa protein was purified from human 293 cells that were infected with a hybrid adenovirus and overexpressed medium tumor antigen. The purified 61-kDa protein was partially digested with protease V8, and one of the protease V8 fragments was isolated and partially sequenced. The amino acid sequence information was used to design mixed oligonucleotide probes for screening a cDNA library from human placenta. A clone was isolated that hybridized with two separate probes; the clone contained an insert with an open reading frame for 589 amino acids. By in vitro translation of the transcript from this insert, a protein was generated that had the same size and yielded the same pattern of protease V8 fragments as the original 61-kDa protein. Its amino acid sequence reveals 15 repeats, the majority of which are 39 amino acids long. This protein bears no resemblance to proteins in the data bank that was searched.
多瘤病毒中肿瘤抗原与几种细胞蛋白形成特异性复合物；其中一种是约61 kDa的蛋白。用针对中肿瘤抗原的抗体，从感染了杂交腺病毒并过表达中肿瘤抗原的人293细胞中纯化出61 kDa蛋白。纯化的61 kDa蛋白用蛋白酶V8进行部分消化，分离出一个蛋白酶V8片段并进行部分测序。氨基酸序列信息用于设计混合寡核苷酸探针，以筛选人胎盘的cDNA文库。分离出一个与两个不同探针杂交的克隆；该克隆包含一个具有589个氨基酸开放阅读框的插入片段。通过体外翻译该插入片段的转录本，产生了一种与原始61 kDa蛋白大小相同且产生相同蛋白酶V8片段模式的蛋白。其氨基酸序列显示有15个重复序列，大多数重复序列长度为39个氨基酸。该蛋白与所搜索的数据库中的蛋白没有相似之处。
