The canonical single-stranded DNA-binding protein is not an essential replication factor but an RNA chaperon in Saccharolobus islandicus
Yuanxi Xiao,
Zhichao Jiang,
Mengqi Zhang,
Xuemei Zhang,
Qi Gan,
Yunfeng Yang,
Pengju Wu,
Xu Feng,
Jinfeng Ni,
Xiuzhu Dong,
Qunxin She,
Qihong Huang,
Yulong Shen
Affiliations
Yuanxi Xiao
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China
Zhichao Jiang
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China
Mengqi Zhang
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China
Xuemei Zhang
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China
Qi Gan
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China
Yunfeng Yang
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China
Pengju Wu
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China
Xu Feng
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China
Jinfeng Ni
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China
Xiuzhu Dong
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
Qunxin She
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China
Qihong Huang
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China; Corresponding author
Yulong Shen
CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao 266237, China; Corresponding author
Summary: Single-stranded DNA-binding proteins (SSBs) have been regarded as indispensable replication factors. Herein, we report that the genes encoding the canonical SSB (SisSSB) and the non-canonical SSB (SisDBP) in Saccharolobus islandicus REY15A are not essential for cell viability. Interestingly, at a lower temperature (55°C), the protein level of SisSSB increases and the growth of ΔSisssb and ΔSisssbΔSisdbp is retarded. SisSSB exhibits melting activity on dsRNA and DNA/RNA hybrid in vitro and is able to melt RNA hairpin in Escherichia coli. Furthermore, the core SisSSB domain is able to complement the absence of cold-shock proteins in E. coli. Importantly, these activities are conserved in the canonical SSBs from Crenarchaeota species that lack bacterial Csp homologs. Overall, our study has clarified the function of the archaeal canonical SSBs which do not function as a DNA-processing factor, but play a role in the processes requiring melting of dsRNA or DNA/RNA hybrid.
