Zurfluh L L, Bolten S L, Byatt J C, McGrath M F, Tou J S, Zupec M E, Krivi G G
Biological Sciences Division, Monsanto Company, St. Louis, Missouri 63198.
Growth Factors. 1990;3(4):257-66. doi: 10.3109/08977199009003668.
Genomic clones encoding bovine TGF-alpha were identified by hybridization with probes derived from human TGF-alpha sequence. Nucleotide sequence of the clones predicts that mature bovine TGF-alpha is a 50 amino acid polypeptide which shares 96% and 92% homology with human and rat TGF-alpha, respectively. Bovine TGF-alpha with the predicted sequence was chemically synthesized and tested for activity. Synthetic bovine TGF-alpha competes in a radioreceptor assay with labelled mouse EGF with activity parallel to that of human TGF-alpha and mouse EGF. The mitogenic activity of bovine TGF-alpha is comparable to that of human EGF in causing proliferation of bovine mammary epithelial cells. An approximately 5.0 kilobase RNA transcript is observed in polyadenylated RNA from MDBK cells by Northern blot analysis. The polymerase chain reaction detects the presence of a TGF-alpha transcript in many bovine tissues. These data indicate that bovine TGF-alpha may be a normal regulator of cell growth in the bovine animal.
通过与人转化生长因子-α（TGF-α）序列衍生的探针杂交，鉴定出编码牛TGF-α的基因组克隆。这些克隆的核苷酸序列预测，成熟的牛TGF-α是一种由50个氨基酸组成的多肽，与人及大鼠TGF-α的同源性分别为96%和92%。化学合成了具有预测序列的牛TGF-α并对其活性进行了检测。合成的牛TGF-α在放射受体分析中与标记的小鼠表皮生长因子（EGF）竞争，其活性与人TGF-α和小鼠EGF相当。在导致牛乳腺上皮细胞增殖方面，牛TGF-α的促有丝分裂活性与人EGF相当。通过Northern印迹分析在MDBK细胞的聚腺苷酸化RNA中观察到一个约5.0千碱基的RNA转录本。聚合酶链反应检测到许多牛组织中存在TGF-α转录本。这些数据表明，牛TGF-α可能是牛动物细胞生长的正常调节因子。
