The small DUF1127 protein CcaF1 from Rhodobacter sphaeroides is an RNA-binding protein involved in sRNA maturation and RNA turnover

Julian Grützner, Fabian Billenkamp, Daniel-Timon Spanka, Tim Rick, Vivian Monzon, Konrad U Förstner, and Gabriele Klug

Nucleic Acids Research, gkab146, doi: 10.1093/nar/gkab146

The DUF1127 domain of CcaF1 displays structural homology to the RNA binding domain of the eukaryotic Smaug protein, which has been implicated in deadenylation of mRNAs targeted for turnover and plays a role in development in yeast, flies and mammalian cells. This study shows that CcaF1 from Rhodobacter sphaeroides is an RNA binding protein that is involved in the maturation of CcsR RNAs and affects the response to oxidative stress and heat stress. Overexpression of CcaF1 results in reduced amounts of mature CcsR RNAs and accumulation of precursor transcripts. Similar results were obtained for a strain with reduced RNase E activity. Together, these findings establish a function for both CcaF1 and this important bacterial endoribonuclease in CcsR transcript maturation. The authors go on to demonstrate that CcaF1 has many additional cellular RNA targets, including mRNAs and tRNAs, and can influence their stability and consequently affect diverse physiological processes.

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