• Title/Summary/Keyword: RNase T1

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Some RNases Involved in the Processing of Bacteriophage T4 RNA (박테리오파지 T4 tRNA의 프로세싱에 관여하는 몇가지 RNase들)

  • Thong-Sung Ko
    • Journal of the Korean Chemical Society
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    • v.26 no.6
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    • pp.396-402
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    • 1982

  • Bacteriophage T4 tRNA processing in E. coli mutant strains defective in RNase Ⅲ, RNase E$^-$, and RNase P, respectively, singly or in combinations, was investigated. In $RNase E^- strains, a RNA band, which would be referred as 9S RNA, accumulates, while in RNase$ P^-$ strains, lower band of 6S double band is accumulated. In RNase III$^-$ strains, the production of tRAN$^{Gln}$ coded by T4 tRNA gene cluster, is severely depressed and also production of species 1 RNA, which is coded by T4 DNA but not by the tRNA gene cluster, is in somewhat depressed amounts; on the other hand, at the same time, an upper band of 6S double bands, coded by T4 tRNA gene cluster, is accumulated in rather greater amounts as compared to the RNase $^+$ strain. The upper band RNA of the 6S double band, however, does not appear to be a precursor to the tRNA$^{Gln}$. The present work points to the lack of evidence for an essential cleavage role of RNase Ⅲ, although there must be a role for the RNase Ⅲ in the T4 tRNA processing.

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RNase P-dependent Cleavage of Polycistronic mRNAs within Their Downstream Coding Regions in Escherichia coli

  • Lee, Jung-Min;Kim, Yool;Hong, Soon-Kang;Lee, Young-Hoon
    • Bulletin of the Korean Chemical Society
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    • v.29 no.6
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    • pp.1137-1140
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    • 2008

  • M1 RNA, the catalytic subunit of Escherichia coli RNase P, is an essential ribozyme that processes the 5' leader sequence of tRNA precursors (ptRNAs). Using KS2003, an E. coli strain generating only low levels of M1 RNA, which showed growth defects, we examined whether M1 RNA is involved in polycistronic mRNA processing or degradation. Microarray analysis of total RNA from KS2003 revealed six polycistronic operon mRNAs (acpP-fabF, cysDNC, flgAMN, lepAB, phoPQ, and puuCBE) showing large differences in expression between the adjacent genes in the same mRNA transcript compared with the KS2001 wild type strain. Model substrates spanning an adjacent pair of genes for each polycistronic mRNA were tested for RNase P cleavage in vitro. Five model RNAs (cysNC, flgMN, lepAB, phoPQ, and puuBE) were cleaved by RNase P holoenzyme but not by M1 RNA alone. However, the cleavages occurred at non-ptRNA-like cleavage sites, with much less efficiency than the cleavage of ptRNA. Since cleavage products generated by RNase P from a polycistronic mRNA can have different in vivo stabilities, our results suggest that RNase P cleavage may lead to differential expression of each cistron.

  • https://doi.org/10.5012/bkcs.2008.29.6.1137 인용 PDF KSCI

Identification and Functional Analysis of Escherichia coli RNase E Mutants (Escherichia coli 리보핵산 내부분해효소 RNase E의 돌연변이체 선별 및 특성분석)

  • Shin, Eun-Kyoung;Go, Ha-Young;Kim, Young-Min;Ju, Se-Jin;Lee, Kang-Seok
    • Korean Journal of Microbiology
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    • v.43 no.4
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    • pp.325-330
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    • 2007

  • RNase E is an essential Escherichia coli endoribonuclease that plays a major role in the decay and processing of a large fraction of RNAs in the cell and expression of N-terminal domain consisted of 1-498 amino acids (N-Rne) is sufficient to support normal cellular growth. By utilizing these properties of RNase E, we developed a genetic system to screen for amino acid substitutions in the catalytic domain of the protein (N-Rne) that lead to various phenotypes. Using this system, we identified three kinds of mutants. A mutant N-Rne containing amino acid substitution in the S1 domain (I6T) of the protein was not able to support survival of E. coli cells, and another mutant N-Rne with amino acid substitution at the position 488 (R488C) in the small domain enabled N-Rne to have an elevated ribonucleolytic activity, while amino acid substitution in the DNase I domain (N305D) only enabled N-Rne to support survival of E. roli cells when the mutant N-Rne was over-expressed. Analysis of copy number of ColEl-type plasmid revealed that effects of amino acid substitution on the ability of N-Rne to support cellular growth stemmed from their differential effects on the ribonucleolytic activity of N-Rne in the cell. These results imply that the genetic system developed in this study can be used to isolate mutant RNase E with various phenotypes, which would help to unveil a functional role of each subdomain of the protein in the regulation of RNA stability in E. coli.

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