title: Rapid degradation of Hfq-free RyhB in Yersinia pestis by PNPase independent of putative ribonucleolytic complexes.
abstract: 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 of Y. pestis RyhB 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 of pnp mRNA from RNase III processing. No significant changes are observed in RyhB stability after deletion of either the PNPase-binding domain of RNase E or rhlB. Therefore, PNPase acts as a major enzyme of RyhB degradation independent of PNPase-containing RNase E and RhlB assembly in the absence of Hfq.
authors.affiliation: Department of Sanitary Inspection, School of Public Health, University of South China, Hengyang, Hunan 421001, China ; State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Zhongliang
authors.initials: Z
authors.lastname: Deng
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Zizhong
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Yujing
authors.initials: Y
authors.lastname: Bi
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Dongsheng
authors.identifier: 0000-0003-3827-5969
authors.initials: D
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Ruifu
authors.initials: R
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Yanping
authors.identifier: 0000-0002-3762-1674
authors.initials: Y
authors.lastname: Han
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D004789:Enzyme Activation; D005095:Exoribonucleases / Q000378:metabolism*; D035001:Host Factor 1 Protein / Q000378:metabolism*; D009154:Mutation; D011485:Protein Binding; D055550:Protein Stability; D059748:Proteolysis; D012329:RNA, Bacterial / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043244:Ribonuclease III / Q000378:metabolism; D014158:Transcription, Genetic; D015010:Yersinia pestis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D035001:Host Factor 1 Protein; D012329:RNA, Bacterial; D012333:RNA, Messenger; D005095:Exoribonucleases; D043244:Ribonuclease III