Ishikawa F, Takaku F, Nagao M, Sugimura T
Carcinogenesis Division, National Cancer Center Research Institute, Tokyo, Japan.
Oncogene Res. 1987 Aug;1(3):243-53.
A-raf gene was first detected by low-stringent hybridization with v-raf and was reported as a possible oncogene. We have cloned rat A-raf cDNA and determined the complete nucleotide sequence over its long open reading frame. Alignment of rat A-raf- and c-raf-deduced amino acid sequences shows 59.4% homology. Both the ATP binding site and the kinase domain are conserved in A-raf as in c-raf. Furthermore, three regions highly conserved between A-raf and c-raf were identified in the 5'-half region of c-raf which has been shown to be deleted in the activated form of c-raf. These regions were speculated to be the candidates of the regulatory domain controlling the protein kinase activity of raf products. Southern blot analysis shows that genes homologous to A-raf and c-raf are present as independent loci in Drosophila melanogaster, Caenorhabditis elegans, Saccharomyces cerevisiae and Candida boidinii. A-raf was expressed in several tissues and cell line at various amounts.
A-raf基因最初是通过与v-raf的低严格度杂交检测到的，并被报道为一种可能的癌基因。我们克隆了大鼠A-raf cDNA，并确定了其长开放阅读框的完整核苷酸序列。大鼠A-raf和c-raf推导的氨基酸序列比对显示同源性为59.4%。A-raf中的ATP结合位点和激酶结构域与c-raf一样保守。此外，在c-raf的5'-半区域鉴定出A-raf和c-raf之间高度保守的三个区域，而该区域在c-raf的活化形式中已被证明缺失。这些区域被推测为控制raf产物蛋白激酶活性的调节结构域的候选区域。Southern印迹分析表明，与A-raf和c-raf同源的基因在果蝇、秀丽隐杆线虫、酿酒酵母和博伊丁假丝酵母中作为独立的基因座存在。A-raf在多种组织和细胞系中以不同量表达。
