Requirement of upstream Hfq-binding (ARN)x elements in glmS and the Hfq C-terminal region for GlmS upregulation by sRNAs GlmZ and GlmY.
Hfq is an important RNA-binding protein that helps bacteria adapt to stress. Its primary function is to promote pairing between trans-acting small non-coding RNAs (sRNAs) and their target mRNAs. Identification of essential Hfq-binding motifs in up-stream regions of rpoS and fhlA led us to ask the question whether these elements are a common occurrence among other Hfq-dependent mRNAs as well. Here, we confirm the presence of a similar (ARN)(x) motif in glmS RNA, a gene controlled by two sRNAs (GlmZ and GlmY) in an Hfq-dependent manner. GlmZ represents a canonical sRNA:mRNA pairing system, whereas GlmY is non-canonical, interfacing with the RNA processing protein YhbJ. We show that glmS interacts with both Hfq-binding surfaces in the absence of sRNAs. Even though two (ARN)(x) motifs are present, using a glmS:gfp fusion system, we determined that only one specific (ARN)(x) element is essential for regulation. Furthermore, we show that residues 66-72 in the C-terminal extension of Escherichia coli Hfq are essential for activation of GlmS expression by GlmY, but not with GlmZ. This result shows that the C-terminal extension of Hfq may be required for some forms of non-canonical sRNA regulation involving ancillary components such as additional RNAs or proteins.
Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
Nilshad N
NN
Salim
Martha A
MA
Faner
Jane A
JA
Philip
Andrew L
AL
Feig
D001426:Bacterial Proteins / Q000378:metabolism; D001665:Binding Sites; D016360:Clostridioides difficile; D003016:Clostridium perfringens; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing) / Q000235:genetics* / Q000378:metabolism; D035001:Host Factor 1 Protein / Q000737:chemistry* / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D059372:Nucleotide Motifs; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000737:chemistry*; D058727:RNA, Small Untranslated / Q000378:metabolism*; D015854:Up-Regulation
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C087373:Hfq protein, E coli; D035001:Host Factor 1 Protein; D012333:RNA, Messenger; D058727:RNA, Small Untranslated; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing)