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Polar‐biased localization of the cold stress‐induced RNA helicase, CrhC, in the Cyanobacterium Anabaena sp. strain PCC 7120
Author(s) -
ElFahmawi Bassam,
Owttrim George W.
Publication year - 2003
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2003.03783.x
Subject(s) - biology , cytoplasm , cell fractionation , rna , rna helicase a , cell membrane , microbiology and biotechnology , subcellular localization , spheroplast , cell , membrane , biochemistry , helicase , gene , escherichia coli
Summary Shift of the filamentous cyanobacterium, Anabaena sp. strain PCC 7120, from 30°C to 20°C induces expression of a cold shock response gene encoding the RNA helicase CrhC. Subcellular localization using cellular fractionation and membrane purification indicated that CrhC is localized to the plasma membrane with no evidence of a soluble‐cytoplasmic form. Treatment of spheroplasts with trypsin and membrane fractions with various denaturing agents identified CrhC as an integral membrane protein associated with the cytoplasmic face of the plasma membrane. Immunoelectron microscopy confirmed the plasma membrane association of CrhC. Interestingly, a higher specific labelling was observed at the cell poles on the septa between adjacent cells within cell filaments. On a per cell area basis, CrhC localization to the cell pole was 3.5‐ and> 1000‐fold higher than to the lateral portion of the plasma membrane or cytoplasm respectively. In addition, CrhC also localizes to new cell poles forming within a dividing cell. Polar‐biased localization of the CrhC RNA helicase implies a role in RNA metabolism that is plasma membrane associated and preferentially occurs at the cell poles during cyanobacterial response to cold stress.