Skip to Main content Skip to Navigation
Theses

Caractérisation des régulateurs transcriptionnels Rgg et étude du rôle de la protéine Rgg0182 de Streptococcus thermophilus

Abstract : Streptococcus thermophilus, bacterium used in dairy industry, is subjected to many environmental changes (oxygen concentration modification, temperature shift, pH variation...) during manufacturing of fermented products. To adapt itself to these modifications, bacterium has defense systems which are controlled by regulation networks involving, in particular, transcriptional regulators. Among them, they are transcriptional regulators of the Rgg family. rgg genes code transcriptional regulators which are very polymorph. Several studies showed their involvement in stress response. The originality of S. thermophilus is the presence of many different rgg copies on genomes of this bacterial species (between 5 and 7 copy according to strain). Objective of this study is the characterization of the Rgg family and study of the S. thermophilus rgg gene function, and, in particular, involvement of these genes in S. thermophilus adaptation to environmental changes. In silico analyses has allowed to show that rgg genes are specific to the Streptocococcaceae family of and the Lactobacillus and the Listeria genus. Proteins belonging to this family are polymorphic and don?t form a monophyletic group. Analyses nevertheless showed that these proteins were characterized by two domains: a "HTH domain" in N-terminal position, very probably involved in the DNA interaction, and a "median domain" in central position which the role remains to determine. Analyses realized during this work show that S. thermophilus LMG18311 rgg0182 gene codes a transcriptional regulator which participates, in particular, in the adaptive response of S. thermophilus exposed to an increase of its growth temperature. Furthermore, the deletion of the rgg0182 gene confers on cells the capacity of a hydrophobic surface adhesion and leads to a reduction of cells chains size. All these phenotypes suggest that Rgg0182 protein is a global regulator of S. thermophilus LMG18311 genic expression. Target genes of this regulator were looked for among genes of thermal stress response and indicate that Rgg0182 protein is involved in the chaperons and proteases homeostasis.
Complete list of metadatas

Cited literature [221 references]  Display  Hide  Download

https://hal.univ-lorraine.fr/tel-01746236
Contributor : Thèses Ul <>
Submitted on : Thursday, March 29, 2018 - 10:28:28 AM
Last modification on : Tuesday, March 17, 2020 - 1:46:59 AM
Long-term archiving on: : Thursday, September 13, 2018 - 12:24:54 PM

File

SCD_T_2011_0087_HENRY.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-01746236, version 1

Citation

Romain Henry. Caractérisation des régulateurs transcriptionnels Rgg et étude du rôle de la protéine Rgg0182 de Streptococcus thermophilus. Bactériologie. Université Henri Poincaré - Nancy 1, 2011. Français. ⟨NNT : 2011NAN10087⟩. ⟨tel-01746236⟩

Share

Metrics

Record views

102

Files downloads

196