Whole-genome microarray and gene deletion studies reveal regulation of the polyhydroxyalkanoate production cycle by the stringent response in Ralstonia eutropha H16.

TitleWhole-genome microarray and gene deletion studies reveal regulation of the polyhydroxyalkanoate production cycle by the stringent response in Ralstonia eutropha H16.
Publication TypeJournal Article
Year of Publication2012
AuthorsBrigham, CJ, Speth, DR, Rha, CK, Sinskey, AJ
JournalAppl Environ Microbiol
Volume78
Issue22
Pagination8033-44
Date Published2012 Nov
ISSN1098-5336
KeywordsCarbon, Culture Media, Cupriavidus necator, Fructose, Gene Deletion, Gene Expression Profiling, Gene Expression Regulation, Bacterial, Polyhydroxyalkanoates, Quaternary Ammonium Compounds
Abstract

Poly(3-hydroxybutyrate) (PHB) production and mobilization in Ralstonia eutropha are well studied, but in only a few instances has PHB production been explored in relation to other cellular processes. We examined the global gene expression of wild-type R. eutropha throughout the PHB cycle: growth on fructose, PHB production using fructose following ammonium depletion, and PHB utilization in the absence of exogenous carbon after ammonium was resupplied. Our results confirm or lend support to previously reported results regarding the expression of PHB-related genes and enzymes. Additionally, genes for many different cellular processes, such as DNA replication, cell division, and translation, are selectively repressed during PHB production. In contrast, the expression levels of genes under the control of the alternative sigma factor σ(54) increase sharply during PHB production and are repressed again during PHB utilization. Global gene regulation during PHB production is strongly reminiscent of the gene expression pattern observed during the stringent response in other species. Furthermore, a ppGpp synthase deletion mutant did not show an accumulation of PHB, and the chemical induction of the stringent response with DL-norvaline caused an increased accumulation of PHB in the presence of ammonium. These results indicate that the stringent response is required for PHB accumulation in R. eutropha, helping to elucidate a thus-far-unknown physiological basis for this process.

DOI10.1128/AEM.01693-12
Alternate JournalAppl Environ Microbiol
Citation Key78
PubMed ID22961894
PubMed Central IDPMC3485964