Coordinate regulation of ribosomal component synthesis in Acanthamoeba castellanii: 5S RNA transcription is down regulated during encystment by alteration of TFIIIA activity.
Coordinate regulation of ribosomal component synthesis in Acanthamoeba castellanii: 5S RNA transcription is down regulated during encystment by alteration of TFIIIA activity.
复制标题
卡氏棘阿米巴核糖体成分合成的协调调节：5S RNA 转录在包囊过程中通过 TFIIIA 活性的改变而下调。
DOI：
10.1128/mcb.15.6.3327
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发表时间：
1995
影响因子：
5.3
通讯作者：
Paule,MR
中科院分区：
文献类型：
--
作者：
Matthews,JL;Zwick,MG;Paule,MR
研究了卡氏阿米巴包囊形成过程中大rRNA前体和5S RNA的转录。在这个过程中，两个转录单位几乎协调地下调，尽管5S RNA转录不像rRNA转录那样完全关闭。确定了5S RNA和tRNA转录所需的蛋白质组分，并鉴定了含有与TFIIIA、TFIIIB和TFIIIC相当的转录因子以及RNA聚合酶III和3′端加工活性的组分。5S RNA转录的调控可以在体外重现，并比较所需组分的活性。与前体rRNA的调节相反，在包囊形成期间，专用于5S RNA表达的聚合酶的活性没有明显变化。类似地，TFIIIC的转录和启动子结合活性不与5S RNA调节平行改变。TFIIIB转录活性在包囊细胞中未改变。与此相反，转录和DNA结合活性的TFIIIA强烈减少在核提取物从转录失活细胞。根据rRNA和5S RNA表达的协调调节机制分析了这些结果。
Transcription of large rRNA precursor and 5S RNA were examined during encystment ofAcanthamoeba castellanii. Both transcription units are down regulated almost coordinately during this process, though 5S RNA transcription is not as completely shut down as rRNA transcription. The protein components necessary for transcription of 5S RNA and tRNA were determined, and fractions containing transcription factors comparable to TFIIIA, TFIIIB, and TFIIIC, as well as RNA polymerase III and a 3′-end processing activity, were identified. Regulation of 5S RNA transcription could be recapitulated in vitro, and the activities of the required components were compared. In contrast to regulation of precursor rRNA, there is no apparent change during encystment in the activity of the polymerase dedicated to 5S RNA expression. Similarly, the transcriptional and promoter-binding activities of TFIIIC are not altered in parallel with 5S RNA regulation. TFIIIB transcriptional activity is unaltered in encysting cells. In contrast, both the transcriptional and DNA-binding activities of TFIIIA are strongly reduced in nuclear extracts from transcriptionally inactive cells. These results were analyzed in terms of mechanisms for coordinate regulation of rRNA and 5S RNA expression.