RNA聚合酶Ⅱ转录延伸因子

当RNA聚合酶Ⅱ(RNAPⅡ)离开启动子开始转录延伸时,会遇到包括紧密包装形成染色质的核小体在内的多种障碍,细胞内存在多种因子可协助RNAPⅡ克服这些障碍,保证转录的顺利进行。遗传和生化研究已经分离和鉴定了一些在此过程中起作用的延伸因子(elongation factor),现依据作用方式和效果对目前发现的主要延伸因子的研究进展进行了分类综述。     

The RNA Polymerase II Factor RPAP1 Is Critical for Mediator-Driven Transcription and Cell Identity

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Porcine Type III RNA Polymerase III Promoters for Short Hairpin RNA Expression

Based on the highly conserved sequences of small nuclear RNA and small cytoplasmic RNA between vertebrate species, three porcine type III RNA polymerase III promoters, pY1, pY3 and pU6, were identified by using genomic DNA walking. To test the functional relationship of these sequences, the human H1 promoter of pSUPER-EGFP-l-neo vector was substituted with these three promoters to create the ppPol III-MCS vectors. The strength of each promoter was measured by its ability to derive expression of shRNA to repress expression of luciferase via RNA interference in the pig kidney epithelial cell line LLC-PK1. We determine that the ranking of promoter strength in descending order is pU6 > pY1 > pY3.