Ssh10b, a conserved thermophilic archaeal protein, binds RNA in vivo.
Proteins of the Sac10b family, which is highly conserved among hyperthermophilic archaea, have been regarded as DNA-binding proteins. Based on their in vitro DNA-binding properties, these proteins are thought to be involved in chromosomal organization or DNA repair/recombination. We show that Ssh10b, a member of the Sac10b family from Sulfolobus shibatae, bound with similar affinities to double-stranded DNA, single-stranded DNA and RNA in vitro. However, the protein was exclusively bound to RNA in S. shibatae cells, as revealed by in vivo UV cross-linking and co-immunoprecipitation. Ribosomal RNAs were among the RNA species co-immunoprecipitated with Ssh10b. Consistent with this observation, Ssh10b was co-purified with ribosomes under low salt conditions. Furthermore, we demonstrate by UV-cross-linking hybridization that, when the cells were irradiated with UV, Ssh10b became cross-linked to 16S, 23S rRNAs and mRNAs. Our data indicate that RNA is the physiological binding target of the Sac10b family.
Guo
Rong
R
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
Xue
Hong
H
Huang
Li
L
D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D011233:Precipitin Tests; D019642:RNA, Archaeal / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012338:RNA, Ribosomal, 23S / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D016944:Sulfolobus / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays
D019843:Archaeal Proteins; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D019642:RNA, Archaeal; D012333:RNA, Messenger; D012338:RNA, Ribosomal, 23S; C119661:Sac10b protein, Sulfolobus acidocaldarius