查看文章

Hfq is a phylogenetically widespread RNA‐binding protein that has emerged as a global regulator of gene expression with a broad impact on bacterial physiology. The symbiotic nitrogen‐fixing α‐proteobacterium Sinorhizobium meliloti expresses an Hfq protein that strongly resembles its well‐characterized enterobacterial counterparts in terms of predicted motifs and secondary/tertiary structures. Hfq loss‐of‐function compromises diverse responses of free‐living rhizobia to stress and the overall symbiotic performance. This phenotypic pleiotropy relies on a large Hfq regulon that involves a wide range of gene functions, including symbiotic nitrogen fixation. Most of the Hfq‐dependent mRNAs are predicted to be posttranscriptionally regulated by the concerted activity of Hfq and its cognate partner trans‐encoded antisense small noncoding RNAs (sRNAs). Recent genome‐wide screens have uncovered the complex …