#### Regulation of transcription initiation and termination of the ssrS gene encoding 6S RNA in Escherichia coli = 대장균 6S RNA를 코드하는 ssrS 유전자의 전사 개시 및 종결의 조절에 관한 연구

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In both prokaryote and eukaryote cells, non-coding RNAs (ncRNAs) play an important role in regulation of gene expression. Among more than 100 small ncRNAs of $\emph{E. coli}$, 6S RNA was the first small ncRNA to be sequenced and its secondary structure was proposed, but identification of its function lagged for many years. 6S RNA inhibits transcription by interacting specifically with $\sigma^{70}$-RNA polymerase ($E\sigma^{70}$) to prevent it from associating with its typical target promoter DNA. Given that 6S RNA functions as a modulator for the $E\sigma^{70}$ activity, 6S RNA biosynthesis should be also regulated according to the cellular requirements for the $E\sigma^{70}$ activity. 6S RNA of about 184 nt, a regulatory RNA for transcription in $\emph{Escherichia coli}$, is generated by processing from primary transcripts. The 5′ processing of the primary transcripts from the $\emph{ssrS}$P1 or P2 promoter is carried out by RNase E and RNase G, while it is not known how the 3′ end of 6S RNA is generated. In this study, it was found that there are several Rho factor-dependent termination sites in the downstream sequence about 90 nt away from the 3′ end of 6S RNA, suggesting that the 3′ end of 6S RNA is generated by exonucleolytic trimming from these termination sites. Since the termination sites are within the open reading frame of the downstream promoterless $\emph{ygfA}$ gene, the data imply that\emph{ygfA} expression, implicated in formation of multidrug-tolerant persister cells, could be regulated by Rho factor activity in the cell. The $\emph{ssrS}$ P1 promoter is a proximal $\sigma^{70}$-dependent promoter and starts transcription initiation at -9, while the $\emph{ssrS}$ P2 promoter is a distal both $\sigma^s$- and $\sigma^{70}$-dependent promoter with the transcription start site at -224. However, it is not known yet how the two promoters contribute to 6S RNA biosynthesis. In this study, the experiment was set out to determine whether transcripti...
Lee, Young-Hoonresearcher이영훈researcher
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
2010
Identifier
455486/325007  / 020045268
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 2010.08, [ viii, 79 p. ]

Keywords

transcription; ygfA; ssrS; 6S RNA; Rho factor; Rho 인자; 전사; ygfA; ssrS; 6S RNA

URI
http://hdl.handle.net/10203/31767