title: Dynamics of speB mRNA transcripts in Streptococcus pyogenes.
abstract: Streptococcus pyogenes (group A streptococcus [GAS]) is a human-specific pathogen that causes a variety of diseases ranging from superficial infections to life-threatening diseases. SpeB, a potent extracellular cysteine proteinase, plays an important role in the pathogenesis of GAS infections. Previous studies show that SpeB expression and activity are controlled at the transcriptional and posttranslational levels, though it had been unclear whether speB was also regulated at the posttranscriptional level. In this study, we examined the growth phase-dependent speB mRNA level and decay using quantitative reverse transcription-PCR (qRT-PCR) and Northern blot analyses. We observed that speB mRNA accumulated rapidly during exponential growth, which occurred concomitantly with an increase in speB mRNA stability. A closer observation revealed that the increased speB mRNA stability was mainly due to progressive acidification. Inactivation of RNase Y, a recently identified endoribonuclease, revealed a role in processing and degradation of speB mRNA. We conclude that the increased speB mRNA stability contributes to the rapid accumulation of speB transcript during growth.
authors.affiliation: Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
authors.forename: Zhiyun
authors.initials: Z
authors.lastname: Chen
authors.forename: Andreas
authors.initials: A
authors.lastname: Itzek
authors.forename: Horst
authors.initials: H
authors.lastname: Malke
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Ferretti
authors.forename: Jens
authors.initials: J
authors.lastname: Kreth
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D015152:Blotting, Northern; D005098:Exotoxins / Q000096:biosynthesis* / Q000235:genetics; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D020871:RNA Stability; D012333:RNA, Messenger / Q000096:biosynthesis*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013297:Streptococcus pyogenes / Q000201:enzymology* / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D005098:Exotoxins; D012333:RNA, Messenger; C027951:erythrogenic toxin