[Dynamic analysis of the heat shock protein 60 and its gene expression in Thermoanaerobacter tengcongensis induced by temperature increase].
Heat shock protein 60 (HSP60) is one of the important chaperonins, which can assist proper protein folding and configuration,and can prevent denaturation and degradation of proteins as well. It was found that HSP60 in Thermoanaerobacter tengcongensis (T. tengcongensis) was typically temperature-dependent with the highest protein expression at 80 degrees C. To understand the molecular mechanisms of thermophiles in their responding to heat stress, further investigation was conducted to examine the dynamic expression of HSP60 gene induced by higher temperature. The T. tengcongensis cells cultured at optimal temperature (75 degrees C) were transferred to 80 degrees C followed by taking the aliquots at different time intervals. To monitor the expression levels of HSP60 mRNA and protein, these bacterial gene products were analyzed by two-dimensional electrophoresis, MALDI-TOF, HPLC-MS/MS, Western blot and quantitative PCR. The experimental data were calculated statistically and quantitatively, which indicate that the HSP60 protein increases steadily and significantly within 4h period after temperature raised, but its mRNA level is shown as a peak shape change within 1h. Obviously, the expression response of HSP60 protein to heat stress is significantly slower than that of its mRNA expression. Additionally, the expression extent of HSP60 mRNA and protein induced by raised-temperature is very different. In E. coli strains, the expression of HSP60 is usually regulated by the sigma32 factor, which disassociates with DnaK immediately when the environmental temperature elevated. Since the genome of T. tengcongensis contains two sigma32 genes, thus, it is likely that both bacteria share the similar mechanisms which regulate HSP60 transcription responding to the changes of temperature. Interestingly, the mRNA of HSP60 drops down about 70% within 30m responding to heat shock, but goes to the increased expression after then. Although this phenomenon is hard to explain based upon the current theory, it is plausible that the transcription in T. tengcongensis is temporally inhibited due to the culture temperature sharply raised.
Meng
Bo
B
Beijing Genomics Institute, Chinese Academy of Sciences, Beijing 101318, China. mengb@genomics.org.cn
Wang
Jing-Qiang
JQ
Li
Na
N
Ma
Yanhe
Y
Liu
Si-Qi
SQ
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018834:Chaperonin 60 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial; D053719:Tandem Mass Spectrometry; D013696:Temperature; D046968:Thermoanaerobacter / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D018834:Chaperonin 60