Transcriptional analysis of the hsp70 gene in a haloarchaeon Natrinema sp. J7 under heat and cold stress

Although ubiquitous in all haloarchaea, little is known about the transcription and regulation of the haloarchaeal hsp70. The purpose of this study is to investigate the transcription of the haloarchaeal hsp70 gene in Natrinema sp. J7 under the temperature and osmotic stress. The hsp70 gene was found to be both temperature- and osmotic-induced, while the response of hsp70 to cold shock was stronger than that to heat shock. Western blot analysis corroborated the similar results at the level of Hsp70 protein. Northern blot and primer extension analyses indicated that the hsp70 was transcribed into a monocistronic transcript and the thermal stress had no effect on the transcription initiation sites choice. The deletion analyses showed that two putative elements, TATA-box (TTTAAAA) and BRE (AGTAAC) located −27 bp upstream of the transcription initiation site played an essential role for the basal transcription of Phsp70. The results suggested that there are some special regulators of hsp70 gene in Natrinema sp. J7.