Translation inhibition of the Salmonella fliC gene by the fliC 5' untranslated region, fliC coding sequences, and FlgM.
The 5'-untranslated region (5'UTR) of the fliC flagellin gene of Salmonella contains sequences critical for efficient fliC mRNA translation coupled to assembly. In a previous study we used targeted mutagenesis of the 5' end of the fliC gene to isolate single base changes defective in fliC gene translation. This identified a predicted stem-loop structure, SL2, as an effector of normal fliC mRNA translation. A single base change (-38C:U) in the fliC 5'UTR resulted in a mutant that is defective in fliC mRNA translation and was chosen for this study. Motile (Mot+) revertants of the -38C:T mutant were isolated and characterized, yielding several unexpected results. Second-site suppressors that restored fliC translation and motility included mutations that disrupt a RNA duplex stem formed between RNA sequences in the fliC 5'UTR SL2 region (including a precise deletion of SL2) and bases early within the fliC-coding region. A stop codon mutation at position 80 of flgM also suppressed the -38C:T motility defect, while flgM mutants defective in anti-sigma28 activity had no effect on fliC translation. One remarkable mutation in the fliC 5'UTR (-15G:A) results in a translation defect by itself but, in combination with the -38C:U mutation, restores normal translation. These results suggests signals intrinsic to the fliC mRNA that have both positive and negative effects on fliC translation involving both RNA structure and interacting proteins.
Rosu
Valentina
V
Department of Microbiology, University of Utah, Salt Lake City, UT 84112, USA.
Chevance
Fabienne F V
FF
Karlinsey
Joyce E
JE
Hirano
Takanori
T
Hughes
Kelly T
KT
D020121:5' Untranslated Regions / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D005407:Flagella; D005408:Flagellin / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D008124:Locomotion; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins; D012486:Salmonella typhimurium / Q000235:genetics* / Q000502:physiology
D020121:5' Untranslated Regions; D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012097:Repressor Proteins; D005408:Flagellin; C071266:FlgM protein, Bacteria