Biomaterial Database

A role for a bacterial ortholog of the Ro autoantigen in starvation-induced rRNA degradation. 2010

Elisabeth J Wurtmann, and Sandra L Wolin

Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06536, USA.

Cellular adaptations to stress often involve changes in RNA metabolism. One RNA-binding protein that has been implicated in RNA handling during environmental stress in both animal cells and prokaryotes is the Ro autoantigen. However, the function of Ro in stress conditions has been unknown. We report that a Ro protein in the radiation-resistant eubacterium Deinococcus radiodurans participates in ribosomal RNA (rRNA) degradation during growth in stationary phase, a form of starvation. Levels of the Ro ortholog Rsr increase dramatically during growth in stationary phase and the presence of Rsr confers a growth advantage. Examination of rRNA profiles reveals that Rsr, the 3' to 5' exoribonuclease polynucleotide phosphorylase (PNP) and additional nucleases are all involved in the extensive rRNA decay that occurs during starvation of this bacterium. We show that Rsr, PNP, and an Rsr-PNP complex exhibit increased sedimentation with ribosomal subunits during stationary phase. As the fractionation of PNP with ribosomal subunits is strongly enhanced in the presence of Rsr, we propose that Ro proteins function as cofactors to increase the association of exonucleases with certain substrates during stress.

UI	MeSH Term	Description	Entries
D012261	Ribonucleoproteins	Complexes of RNA-binding proteins with ribonucleic acids (RNA).	Ribonucleoprotein
D012329	RNA, Bacterial	Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.	Bacterial RNA
D012335	RNA, Ribosomal	The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)	Ribosomal RNA,15S RNA,RNA, 15S
D015152	Blotting, Northern	Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.	Northern Blotting,Blot, Northern,Northern Blot,Blots, Northern,Blottings, Northern,Northern Blots,Northern Blottings
D034301	Deinococcus	A genus of gram-positive aerobic cocci found in the soil, that is highly resistant to radiation, especially ionizing radiation (RADIATION, IONIZING). Deinococcus radiodurans is the type species.	Deinococcus radiodurans