scholarly journals Rapid Degradation of Hfq-Free RyhB inYersinia pestisby PNPase Independent of Putative Ribonucleolytic Complexes

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Zhongliang Deng ◽  
Zizhong Liu ◽  
Yujing Bi ◽  
Xiaoyi Wang ◽  
Dongsheng Zhou ◽  
...  
Keyword(s):  
Rna Helicase ◽  
Binding Domain ◽  
Rnase E ◽  
Rnase Iii ◽  
Rna Chaperone ◽  
Rapid Degradation ◽  
Transcript Levels

The RNA chaperone Hfq in bacteria stabilizes sRNAs by protecting them from the attack of ribonucleases. Upon release from Hfq, sRNAs are preferably degraded by PNPase. PNPase usually forms multienzyme ribonucleolytic complexes with endoribonuclease E and/or RNA helicase RhlB to facilitate the degradation of the structured RNA. However, whether PNPase activity on Hfq-free sRNAs is associated with the assembly of RNase E or RhlB has yet to be determined. Here we examined the roles of the main endoribonucleases, exoribonucleases, and ancillary RNA-modifying enzymes in the degradation ofY. pestisRyhB in the absence of Hfq. Expectedly, the transcript levels of both RyhB1 and RyhB2 increase only after inactivating PNPase, which confirms the importance of PNPase in sRNA degradation. By contrast, the signal of RyhB becomes barely perceptible after inactivating of RNase III, which may be explained by the increase in PNPase levels resulting from the exemption ofpnpmRNA from RNase III processing. No significant changes are observed in RyhB stability after deletion of either the PNPase-binding domain of RNase E orrhlB. Therefore, PNPase acts as a major enzyme of RyhB degradation independent of PNPase-containing RNase E and RhlB assembly in the absence of Hfq.

scholarly journals Association of the Cold Shock DEAD-Box RNA Helicase RhlE to the RNA Degradosome in Caulobacter crescentus

2017 ◽  
Vol 199 (13) ◽  
Author(s):  
Angel A. Aguirre ◽  
Alexandre M. Vicente ◽  
Steven W. Hardwick ◽  
Daniela M. Alvelos ◽  
Ricardo R. Mazzon ◽  
...  
Keyword(s):  
Low Temperature ◽  
Caulobacter Crescentus ◽  
Immunoblot Analysis ◽  
Rna Helicase ◽  
Rnase E ◽  
Rna Helicases ◽  
Content Type ◽  
Dead Box ◽  
Rna Degradosome ◽  
The Dead

ABSTRACT In diverse bacterial lineages, multienzyme assemblies have evolved that are central elements of RNA metabolism and RNA-mediated regulation. The aquatic Gram-negative bacterium Caulobacter crescentus, which has been a model system for studying the bacterial cell cycle, has an RNA degradosome assembly that is formed by the endoribonuclease RNase E and includes the DEAD-box RNA helicase RhlB. Immunoprecipitations of extracts from cells expressing an epitope-tagged RNase E reveal that RhlE, another member of the DEAD-box helicase family, associates with the degradosome at temperatures below those optimum for growth. Phenotype analyses of rhlE, rhlB, and rhlE rhlB mutant strains show that RhlE is important for cell fitness at low temperature and its role may not be substituted by RhlB. Transcriptional and translational fusions of rhlE to the lacZ reporter gene and immunoblot analysis of an epitope-tagged RhlE indicate that its expression is induced upon temperature decrease, mainly through posttranscriptional regulation. RNase E pulldown assays show that other proteins, including the transcription termination factor Rho, a second DEAD-box RNA helicase, and ribosomal protein S1, also associate with the degradosome at low temperature. The results suggest that the RNA degradosome assembly can be remodeled with environmental change to alter its repertoire of helicases and other accessory proteins. IMPORTANCE DEAD-box RNA helicases are often present in the RNA degradosome complex, helping unwind secondary structures to facilitate degradation. Caulobacter crescentus is an interesting organism to investigate degradosome remodeling with change in temperature, because it thrives in freshwater bodies and withstands low temperature. In this study, we show that at low temperature, the cold-induced DEAD-box RNA helicase RhlE is recruited to the RNA degradosome, along with other helicases and the Rho protein. RhlE is essential for bacterial fitness at low temperature, and its function may not be complemented by RhlB, although RhlE is able to complement for rhlB loss. These results suggest that RhlE has a specific role in the degradosome at low temperature, potentially improving adaptation to this condition.

7S RNA, containing 5S ribosomal RNA and the termination stem, is a specific substrate for the two RNA processing enzymes RNase III and RNase E

Biochemistry ◽  
1984 ◽  
Vol 23 (13) ◽  
pp. 2952-2957 ◽  
Author(s):  
Jozsef Szeberenyi ◽  
Monoj K. Roy ◽  
Hemant C. Vaidya ◽  
David Apirion
Keyword(s):  
Ribosomal Rna ◽  
Rna Processing ◽  
Specific Substrate ◽  
Rnase E ◽  
Rnase Iii ◽  
5S Ribosomal Rna ◽  
Processing Enzymes

scholarly journals The bacterial endoribonuclease RNase E can cleave RNA in the absence of the RNA chaperone Hfq

2019 ◽  
Vol 294 (44) ◽  
pp. 16465-16478 ◽  
Author(s):  
Yu Mi Baek ◽  
Kyoung-Jin Jang ◽  
Hyobeen Lee ◽  
Soojin Yoon ◽  
Ahruem Baek ◽  
...  
Keyword(s):  
Rnase E ◽  
Rna Chaperone

scholarly journals Two distinct regions on the surface of an RNA-binding domain are crucial for RNase E function

2003 ◽  
Vol 47 (4) ◽  
pp. 1183-1183
Author(s):  
Alexis A. Diwa ◽  
Xunqing Jiang ◽  
Matthieu Schapira ◽  
Joel G. Belasco
Keyword(s):  
Rna Binding ◽  
Binding Domain ◽  
Rnase E ◽  
Rna Binding Domain

scholarly journals Disruption of an RNA helicase/RNAse III gene in Arabidopsis causes unregulated cell division in floral meristems

Development ◽  
1999 ◽  
Vol 126 (23) ◽  
pp. 5231-5243 ◽  
Author(s):  
S.E. Jacobsen ◽  
M.P. Running ◽  
E.M. Meyerowitz
Keyword(s):  
Cell Division ◽  
Rna Helicase ◽  
Helicase Domain ◽  
Rnase Iii ◽  
Dead Box ◽  
Processing Event ◽  
Recessive Mutant ◽  
Floral Meristems ◽  
Axillary Inflorescence

Arabidopsis thaliana floral meristems are determinate structures that produce a defined number of organs, after which cell division ceases. A new recessive mutant, carpel factory (caf), converts the floral meristems to an indeterminate state. They produce extra whorls of stamens, and an indefinite number of carpels. Thus, CAF appears to suppress cell division in floral meristems. The function of CAF is partially redundant with the function of the CLAVATA (CLV) and SUPERMAN (SUP) genes, as caf clv and caf sup double mutants show dramatically enhanced floral meristem over-proliferation. caf mutant plants also show other defects, including absence of axillary inflorescence meristems, and abnormally shaped leaves and floral organs. The CAF gene was cloned and found to encode a putative protein of 1909 amino acids containing an N-terminal DExH/DEAD-box type RNA helicase domain attached to a C-terminal RNaseIII-like domain. A very similar protein of unknown function is encoded by a fungal and an animal genome. Helicase proteins are involved in a number of processes, including specific mRNA localization and mRNA splicing. RNase III proteins are involved in the processing of rRNA and some mRNA molecules. Thus CAF may act through some type of RNA processing event(s). CAF gives rise to two major transcripts of 2.5 and 6.2 kb. In situ hybridization experiments show that CAF RNA is expressed throughout all shoot tissues.

scholarly journals RNA helicase–regulated processing of the Synechocystis rimO–crhR operon results in differential cistron expression and accumulation of two sRNAs

2020 ◽  
Vol 295 (19) ◽  
pp. 6372-6386 ◽  
Author(s):  
Albert Remus R. Rosana ◽  
Denise S. Whitford ◽  
Anzhela Migur ◽  
Claudia Steglich ◽  
Sonya L. Kujat-Choy ◽  
...  
Keyword(s):  
Small Rnas ◽  
Rna Helicase ◽  
Rnase E ◽  
Gene Encoding ◽  
Modeling And Analysis ◽  
Dead Box ◽  
Bacterial Rna ◽  
Additional Processing ◽  
Operon Expression

The arrangement of functionally-related genes in operons is a fundamental element of how genetic information is organized in prokaryotes. This organization ensures coordinated gene expression by co-transcription. Often, however, alternative genetic responses to specific stress conditions demand the discoordination of operon expression. During cold temperature stress, accumulation of the gene encoding the sole Asp–Glu–Ala–Asp (DEAD)-box RNA helicase in Synechocystis sp. PCC 6803, crhR (slr0083), increases 15-fold. Here, we show that crhR is expressed from a dicistronic operon with the methylthiotransferase rimO/miaB (slr0082) gene, followed by rapid processing of the operon transcript into two monocistronic mRNAs. This cleavage event is required for and results in destabilization of the rimO transcript. Results from secondary structure modeling and analysis of RNase E cleavage of the rimO–crhR transcript in vitro suggested that CrhR plays a role in enhancing the rate of the processing in an auto-regulatory manner. Moreover, two putative small RNAs are generated from additional processing, degradation, or both of the rimO transcript. These results suggest a role for the bacterial RNA helicase CrhR in RNase E-dependent mRNA processing in Synechocystis and expand the known range of organisms possessing small RNAs derived from processing of mRNA transcripts.

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