TY - JOUR
T1 - Growth phase-dependent variation of RNase BN/Z affects small RNAs
AU - Chen, Hua
AU - Dutta, Tanmay
AU - Deutscher, Murray P.
N1 - Funding Information:
This work was supported by National Institutes of Health Grant GM16317 (to M. P. D.). The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
PY - 2016/12/16
Y1 - 2016/12/16
N2 - RNase BN, the RNase Z family member in E. coli, can participate in the processing of tRNA precursors. However, this function only becomes apparent when other processing enzymes are absent, raising the question of its primary physiological role. Here, we show that RNase BN itself is subject to growth phasedependent regulation, because both rbn mRNA and RNase BN protein are at their highest levels in early exponential phase, but then decrease dramatically and are essentially absent in stationary phase. As a consequence of this variation, certain small RNAs, such as 6S RNA, remain low in exponential phase cells, and increase greatly in stationary phase. RNase BN affects 6S RNAabundance by decreasing its stability in exponential phase. RNase BN levels increase rapidly as cells exit stationary phase and are primarily responsible for the decrease in 6S RNA that accompanies this process. Purified RNaseBNdirectly cleaves 6S RNA as shown by in vitro assays, and the 6S RNA:pRNA duplex is an even more favorable substrate of RNase BN. The exoribonuclease activity of RNase BN is unnecessary because all its action on 6S RNA is due to endonucleolytic cleavages. These data indicate that RNase BN plays an important role in determining levels of the global transcription regulator, 6S RNA, throughout the growth cycle.
AB - RNase BN, the RNase Z family member in E. coli, can participate in the processing of tRNA precursors. However, this function only becomes apparent when other processing enzymes are absent, raising the question of its primary physiological role. Here, we show that RNase BN itself is subject to growth phasedependent regulation, because both rbn mRNA and RNase BN protein are at their highest levels in early exponential phase, but then decrease dramatically and are essentially absent in stationary phase. As a consequence of this variation, certain small RNAs, such as 6S RNA, remain low in exponential phase cells, and increase greatly in stationary phase. RNase BN affects 6S RNAabundance by decreasing its stability in exponential phase. RNase BN levels increase rapidly as cells exit stationary phase and are primarily responsible for the decrease in 6S RNA that accompanies this process. Purified RNaseBNdirectly cleaves 6S RNA as shown by in vitro assays, and the 6S RNA:pRNA duplex is an even more favorable substrate of RNase BN. The exoribonuclease activity of RNase BN is unnecessary because all its action on 6S RNA is due to endonucleolytic cleavages. These data indicate that RNase BN plays an important role in determining levels of the global transcription regulator, 6S RNA, throughout the growth cycle.
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U2 - 10.1074/jbc.M116.757450
DO - 10.1074/jbc.M116.757450
M3 - Article
C2 - 27875308
AN - SCOPUS:85006314660
VL - 291
SP - 26435
EP - 26442
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 51
ER -