The Streptococcus mutans IrvR repressor is a CI-like regulator that functions through autocleavage and Clp-dependent proteolysis

Guoqing Niu, Toshinori Okinaga, Fengxia Qi, Justin Merritt

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Previous work has shown that irvR is required for the proper regulation of genetic competence and dextran-dependent aggregation due to its ability to repress the transcription regulator irvA. In this study, we determined the mechanism used to relieve the repression of irvA. We demonstrate that IrvR is a "LexA-like" protein with four conserved amino acid residues likely required for IrvR autocleavage activity. Furthermore, recombinant IrvR protein purified from Escherichia coli was competent to undergo autocleavage in vitro. Using several truncated IrvR constructs, we show that the amino acids adjacent to the autocleavage site are essential for relieving irvA repression and engaging the irvA-dependent regulatory pathway primarily through the ClpXP and ClpCP proteases. By extending the IrvR C terminus with an epitope derived from the autocleavage site, we were also able to create a constitutive Clp-dependent degradation of the full-length IrvR protein. This suggests that the derepression of irvA occurs through a two-step mechanism involving the initial autocleavage of IrvR and exposure of a proteolytic degradation sequence followed by Clp-dependent degradation of the IrvR DNA binding domain. Thus, irvA derepression is highly analogous to the genetic switch mechanism used to regulate lysogeny in bacteriophages.

Original languageEnglish (US)
Pages (from-to)1586-1595
Number of pages10
JournalJournal of Bacteriology
Volume192
Issue number6
DOIs
StatePublished - Mar 2010
Externally publishedYes

Fingerprint

Streptococcus mutans
Proteolysis
Lysogeny
Amino Acids
Aptitude
Dextrans
Recombinant Proteins
Bacteriophages
Mental Competency
Epitopes
Proteins
Peptide Hydrolases
Escherichia coli
DNA
In Vitro Techniques

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

Cite this

The Streptococcus mutans IrvR repressor is a CI-like regulator that functions through autocleavage and Clp-dependent proteolysis. / Niu, Guoqing; Okinaga, Toshinori; Qi, Fengxia; Merritt, Justin.

In: Journal of Bacteriology, Vol. 192, No. 6, 03.2010, p. 1586-1595.

Research output: Contribution to journalArticle

@article{c74b5d8f61e9440380fdddab628ac5fe,
title = "The Streptococcus mutans IrvR repressor is a CI-like regulator that functions through autocleavage and Clp-dependent proteolysis",
abstract = "Previous work has shown that irvR is required for the proper regulation of genetic competence and dextran-dependent aggregation due to its ability to repress the transcription regulator irvA. In this study, we determined the mechanism used to relieve the repression of irvA. We demonstrate that IrvR is a {"}LexA-like{"} protein with four conserved amino acid residues likely required for IrvR autocleavage activity. Furthermore, recombinant IrvR protein purified from Escherichia coli was competent to undergo autocleavage in vitro. Using several truncated IrvR constructs, we show that the amino acids adjacent to the autocleavage site are essential for relieving irvA repression and engaging the irvA-dependent regulatory pathway primarily through the ClpXP and ClpCP proteases. By extending the IrvR C terminus with an epitope derived from the autocleavage site, we were also able to create a constitutive Clp-dependent degradation of the full-length IrvR protein. This suggests that the derepression of irvA occurs through a two-step mechanism involving the initial autocleavage of IrvR and exposure of a proteolytic degradation sequence followed by Clp-dependent degradation of the IrvR DNA binding domain. Thus, irvA derepression is highly analogous to the genetic switch mechanism used to regulate lysogeny in bacteriophages.",
author = "Guoqing Niu and Toshinori Okinaga and Fengxia Qi and Justin Merritt",
year = "2010",
month = "3",
doi = "10.1128/JB.01261-09",
language = "English (US)",
volume = "192",
pages = "1586--1595",
journal = "Journal of Bacteriology",
issn = "0021-9193",
publisher = "American Society for Microbiology",
number = "6",

}

TY - JOUR

T1 - The Streptococcus mutans IrvR repressor is a CI-like regulator that functions through autocleavage and Clp-dependent proteolysis

AU - Niu, Guoqing

AU - Okinaga, Toshinori

AU - Qi, Fengxia

AU - Merritt, Justin

PY - 2010/3

Y1 - 2010/3

N2 - Previous work has shown that irvR is required for the proper regulation of genetic competence and dextran-dependent aggregation due to its ability to repress the transcription regulator irvA. In this study, we determined the mechanism used to relieve the repression of irvA. We demonstrate that IrvR is a "LexA-like" protein with four conserved amino acid residues likely required for IrvR autocleavage activity. Furthermore, recombinant IrvR protein purified from Escherichia coli was competent to undergo autocleavage in vitro. Using several truncated IrvR constructs, we show that the amino acids adjacent to the autocleavage site are essential for relieving irvA repression and engaging the irvA-dependent regulatory pathway primarily through the ClpXP and ClpCP proteases. By extending the IrvR C terminus with an epitope derived from the autocleavage site, we were also able to create a constitutive Clp-dependent degradation of the full-length IrvR protein. This suggests that the derepression of irvA occurs through a two-step mechanism involving the initial autocleavage of IrvR and exposure of a proteolytic degradation sequence followed by Clp-dependent degradation of the IrvR DNA binding domain. Thus, irvA derepression is highly analogous to the genetic switch mechanism used to regulate lysogeny in bacteriophages.

AB - Previous work has shown that irvR is required for the proper regulation of genetic competence and dextran-dependent aggregation due to its ability to repress the transcription regulator irvA. In this study, we determined the mechanism used to relieve the repression of irvA. We demonstrate that IrvR is a "LexA-like" protein with four conserved amino acid residues likely required for IrvR autocleavage activity. Furthermore, recombinant IrvR protein purified from Escherichia coli was competent to undergo autocleavage in vitro. Using several truncated IrvR constructs, we show that the amino acids adjacent to the autocleavage site are essential for relieving irvA repression and engaging the irvA-dependent regulatory pathway primarily through the ClpXP and ClpCP proteases. By extending the IrvR C terminus with an epitope derived from the autocleavage site, we were also able to create a constitutive Clp-dependent degradation of the full-length IrvR protein. This suggests that the derepression of irvA occurs through a two-step mechanism involving the initial autocleavage of IrvR and exposure of a proteolytic degradation sequence followed by Clp-dependent degradation of the IrvR DNA binding domain. Thus, irvA derepression is highly analogous to the genetic switch mechanism used to regulate lysogeny in bacteriophages.

UR - http://www.scopus.com/inward/record.url?scp=77949342122&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77949342122&partnerID=8YFLogxK

U2 - 10.1128/JB.01261-09

DO - 10.1128/JB.01261-09

M3 - Article

C2 - 20038591

AN - SCOPUS:77949342122

VL - 192

SP - 1586

EP - 1595

JO - Journal of Bacteriology

JF - Journal of Bacteriology

SN - 0021-9193

IS - 6

ER -