Transcriptome analysis of adaptive heat shock response of Streptococcus thermophilus.
Streptococcus thermophilus, a gram-positive facultative anaerobe, is one of the most important lactic acid bacteria widely used in the dairy fermentation industry. In this study, we have analyzed the global transcriptional profiling of S. thermophilus upon temperature change. During a temperature shift from 42°C to 50°C, it is found that 196 (10.4%) genes show differential expression with 102 up-regulated and 94 down-regulated at 50°C. In particular, 1) Heat shock genes, such as DnaK, GroESL and clpL, are identified to be elevated at 50°C; 2) Transcriptional regulators, such as HrcA, CtsR, Fur, MarR and MerR family, are differentially expressed, indicating the complex molecular mechanisms of S. thermophilus adapting to heat shock; 3) Genes associated with signal transduction, cell wall genes, iron homeostasis, ABC transporters and restriction-modification system were induced; 4) A large number of the differentially expressed genes are hypothetical genes of unknown function, indicating that much remains to be investigated about the heat shock response of S. thermophilus. Experimental investigation of selected heat shock gene ClpL shows that it plays an important role in the physiology of S. thermophilus at high temperature and meanwhile we confirmed ClpL as a member of the CtsR regulon. Overall, this study has contributed to the underlying adaptive molecular mechanisms of S. thermophilus upon temperature change and provides a basis for future in-depth functional studies.
College of Life Science, Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, China.
Jin-song
JS
Li
Yun-tian
YT
Bi
Cheng
C
Dong
Ji-feng
JF
Yang
Wan-dong
WD
Liang
D000222:Adaptation, Physiological / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D030541:Databases, Genetic; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D018869:Heat-Shock Response / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D015203:Reproducibility of Results; D015398:Signal Transduction / Q000235:genetics; D048249:Streptococcus thermophilus / Q000235:genetics*; D013696:Temperature; D014158:Transcription, Genetic; D059467:Transcriptome
D001426:Bacterial Proteins; D008565:Membrane Proteins