Wang S C, Lin S H, Su L K, Hung M C
Department of Tumor Biology, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
Biochem Biophys Res Commun. 1997 May 8;234(1):247-51. doi: 10.1006/bbrc.1997.6544.
It has been shown that genetic alterations in BRCA1 and BRCA2 can predispose an individual to develop breast cancer. We investigated the expression of both BRCA2 and BRCA1 during the progression of the cell cycle by northern blot analysis. In MCF-10F (normal breast epithelial cell line) and MCF-7 (breast cancer cell line) cells the expression of BRCA2 RNA was low in G0 and early G1 phases then up-regulated at the G1/S phase junction. Expression of BRCA2 was maintained at relatively high levels when cells progressed through S and G2/M phases. For MCF-7 cells, the level of BRCA2 transcript decreased as cells were released from nocodazole-mediated metaphase arrest. This is consistent with the observation of low but detectable BRCA2 RNA level in G1 phase of the cell cycle. For both cell lines, the patterns of RNA expression of BRCA1 and BRCA2 were similar during the proliferation phase of cell cycle. However, the transcripts from both genes were undetectable in quiescent cells. These results suggest important functions for both BRCA2 and BRCA1 in regulation of cell growth.
研究表明，BRCA1和BRCA2的基因改变会使个体易患乳腺癌。我们通过Northern印迹分析研究了细胞周期进程中BRCA2和BRCA1的表达情况。在MCF-10F（正常乳腺上皮细胞系）和MCF-7（乳腺癌细胞系）细胞中，BRCA2 RNA的表达在G0期和G1早期较低，然后在G1/S期交界处上调。当细胞进入S期和G2/M期时，BRCA2的表达维持在相对较高的水平。对于MCF-7细胞，当细胞从诺考达唑介导的中期阻滞中释放时，BRCA2转录本的水平降低。这与在细胞周期G1期观察到的低但可检测到的BRCA2 RNA水平一致。对于这两种细胞系，在细胞周期的增殖阶段，BRCA1和BRCA2的RNA表达模式相似。然而，在静止细胞中未检测到这两个基因的转录本。这些结果表明BRCA2和BRCA1在细胞生长调节中具有重要功能。
