辐射诱导基因LRIGx的细胞周期特异性表达及编码产物同源性分析

Cell Cycle Dependent Expression of Radiation-induced Gene LRIGx and The Homologous Comparison of Its Encoding Product

低剂量辐射诱导表达新基因LRIGx被克隆 .Northern印迹杂交结果表明 ,在 0 2Gyγ射线照射后 2～ 4h ,人A5 4 9细胞中该基因mRNA表达水平显著上调 .当照射剂量增加到 2Gy时 ,其诱导表达水平明显低于 0 2Gy照射 .通过细胞周期同步化 ,观察到LRIGx基因表达高峰在G2 M期 .同源性比较和功能保守域分析结果显示 ,该基因编码产物与DNA修复和重组蛋白RAD5 4、ERCC 6 ,染色质重构和转录调节功能蛋白SWI2 SNF2等有同源性 ,其N端具有与染色质重构、基因转录调控和DNA修复有关的 3个功能结构域 ,即CHROMO。

A novel low dose radiation induced expression gene named LRIGx was cloned. Northern analysis revealed that the mRNA level of LRIGx was significantly up regulated in A549 cells at 2～4 hours after 0 2 Gy of γ ray exposure. However, the induced level of LRIGx mRNA by 2 0 Gy was not so significant as that by 0 2 Gy low dose exposure. Using synchronized cells, an expression peak of LRIGx mRNA was observed in G 2/M phase cells. The results of homologous comparison indicated that the N terminal of LRIGx encoding product contained some identical domains with DNA repair and recombination protein RAD54, ERCC 6, chromosome remodeling and transcription regulating protein SWI2/SNF2. These domains included CHROMO, SNF2N and helicase C.