Robbins J, Blondel B J, Gallahan D, Callahan R
Laboratory of Tumor Immunology and Biology, National Cancer Institute, Bethesda, Maryland 20892.
J Virol. 1992 Apr;66(4):2594-9. doi: 10.1128/JVI.66.4.2594-2599.1992.
Expression of a 2.3-kb RNA species is induced in mammary tumors as a consequence of insertional mutagenesis at the int-3 locus by the mouse mammary tumor virus. The nucleotide sequence and biological activity of this mammary tumor-specific int-3 RNA species were determined. It contains an open reading frame which encodes a 57-kDa protein. The translated protein possesses six nearly contiguous 32-amino-acid repeats which are related to a similar motif in the Saccharomyces cerevisiae cdc-10-encoded cell cycle protein. In addition, the int-3 cdc-10 repeats are bounded by the PEST amino acid sequence motif which is commonly found in proteins having a rapid turnover and may represent sites for phosphorylation. The int-3 cdc-10 repeat sequences are 50% identical to a portion of the intracellular domain of the neurogenic Drosophila notch gene product. Activation of expression of a recombinant int-3 genomic DNA fragment encoding the 2.3-kb RNA species in HC11 mouse mammary epithelial cells in vitro induces anchorage-independent growth in soft agar.
由于小鼠乳腺肿瘤病毒在int-3位点发生插入诱变，在乳腺肿瘤中诱导出一种2.3 kb RNA物种的表达。测定了这种乳腺肿瘤特异性int-3 RNA物种的核苷酸序列和生物学活性。它包含一个开放阅读框，编码一种57 kDa的蛋白质。翻译后的蛋白质具有六个几乎相邻的32个氨基酸的重复序列，这些重复序列与酿酒酵母cdc-10编码的细胞周期蛋白中的类似基序相关。此外，int-3 cdc-10重复序列由PEST氨基酸序列基序界定，该基序常见于周转迅速的蛋白质中，可能代表磷酸化位点。int-3 cdc-10重复序列与神经源性果蝇Notch基因产物细胞内结构域的一部分有50%的同源性。在体外，编码2.3 kb RNA物种的重组int-3基因组DNA片段在HC11小鼠乳腺上皮细胞中的表达激活可诱导软琼脂中不依赖贴壁的生长。
