Microarray studies reveal a 'differential response' to moderate or severe heat shock of the HrcA- and HspR-dependent systems in Corynebacterium glutamicum

• Published in: Microbiology (Society for General Microbiology) Vol. 155; no. 2; pp. 359 - 372
• Main Authors: Barreiro, Carlos, Nakunst, Diana, Huser, Andrea T, de Paz, Hector D, Kalinowski, Jorn, Martin, Juan F
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01-02-2009; Society for General Microbiology
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological and medical sciences; Corynebacterium glutamicum - genetics; Corynebacterium glutamicum - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial; Heat-Shock Proteins - genetics; Heat-Shock Proteins - metabolism; Heat-Shock Response; Microbiology; Oligonucleotide Array Sequence Analysis; Repressor Proteins - genetics; Repressor Proteins - metabolism; Transcription, Genetic; Bacteria; Actinomycetes; Corynebacteriaceae; Corynebacterium glutamicum
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.019299-0

1 INBIOTEC (Instituto de Biotecnología de León), Parque Científico de León, Avda. Real, 1, 24006 León, Spain
2 Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstrasse 25, 33615 Bielefeld, Germany
3 Área de Microbiología, Departamento de Biología Molecular, Universidad de León, Campus de Vegazana, s/n. 24071 León, Spain
Correspondence Juan F. Martín jf.martin{at}unileon.es
Genome-wide transcription profile analysis of the heat-shocked wild-type strain under moderate (40 °C) and severe heat stress (50 °C) revealed that a large number of genes are differentially expressed after heat shock. Of these, 358 genes were upregulated and 420 were downregulated in response to moderate heat shock (40 °C) in Corynebacterium glutamicum . Our results confirmed the HrcA/controlling inverted repeat of chaperone expression (CIRCE)-dependent and HspR/HspR-associated inverted repeat (HAIR)-dependent upregulation of chaperones following heat shock. Other genes, including clusters of orthologous groups (COG) related to macromolecule biosynthesis and several transcriptional regulators (COG class K), were upregulated, explaining the large number of genes affected by heat shock. Mutants having deletions in the hrcA or hspR regulators were constructed, which allowed the complete identification of the genes controlled by those systems. The up- or downregulation of several genes observed in the microarray experiments was validated by Northern blot analyses and quantitative (real-time) reverse-transcription PCR. These analyses showed a heat-shock intensity-dependent response (‘differential response’) in the HspR/HAIR system, in contrast to the non-differential response shown by the HrcA/CIRCE-regulated genes.
Abbreviations: CIRCE, controlling inverted repeat of chaperone expression; COG, clusters of orthologous groups; CtsR, class three stress gene repressor; HAIR, HspR-associated inverted repeat; q-RT-PCR, quantitative (real-time) reverse-transcription PCR; ROSE, repression of heat-shock gene expression
The array data discussed in this paper have been deposited in EBI and are accessible through ArrayExpress series accession number E-MTAB-66.
Tables of microarray data are available as supplementary material with the online version of this paper.