真核细胞中mRNA的降解机制

The Mechanisms of mRNA Degradation in Eukaryotes

细胞中不同的ｍ ＲＮＡ 半寿期差异很大，ｍ ＲＮＡ 的稳定性受到多种因素的影响，现在已经发现了许多对ｍ ＲＮＡ 的稳定性有影响的顺式因子和反式因子。大量的研究证明在真核细胞内存在复杂的机制调节ｍ ＲＮＡ 的稳定与降解及其所引起的基因表达。现在可以肯定在真核细胞中至少存在着三种ｍ ＲＮＡ的降解方式：依赖于脱腺苷酸的降解，无义密码介导的ｍ ＲＮＡ 的降解和核酸内切酶的水解。其中依赖于脱腺苷酸的降解方式是细胞内大多数ｍ ＲＮＡ 降解的主要途径。

The half-lives of different mRNAs in Eukaryotic cells vary greatly. There are many elements can influence mRNA stability, including cis-acting factors and trans-acting factors. Evidences show that there exist complicated mechanisms in cells that regulate mRNA stability, degradation and expression. Recent results have defined three mRNA degradation pathways in Eukaryotic cells: deadenylation-dependent mRNA decay, nonsense-mediated mRNA decay and endonuclolytic cleavage. Among these pathways deadenylation-dependent decay is the most general pathway. Keyword: mRNA; degradation; Eukarotesing FCM, it was shown that NCP4 cells exhibited decreased percentage in G1 phase, increased percentage in S phase and G2+M phase. In contrast to control cells, NCP4 cells overexpressing PKC γ decreased anchorage dependence and formed small colonies in soft agar. Furthermore, it was observed that the expression of oncogene c sis increased obviously in NCP4 cells, it may be one of the molecular mechanisms of the reduced dependence on serum in NCP4 cells. The results indicated that specific elevation of the PKC γ level directly affected the increase of growth rate and lead to some transforming phenotypes in C 3H 10 T 1/2 cells.