关键词: 耐辐射异常球菌；&sigma, 因子；Sig2；高温胁迫

Abstract: σ factor, a subunit of RNA polymerase in prokaryotes, can activate transcriptional initiation through a kind of reversible bind with the active catalytic sites of RNA polymerase core enzyme，promote the accurate identification of RNA polymerase to transcriptional initiation site and eventually activate the expression of corresponding genes specifically. With the strong capacity and environmental adaptability to radiation, oxidation and high temperature，Deinococcus radiodurans（D. radiodurans）contains three σ factors，among which Sig2 may function significantly in its strong environmental suitability. In this study，we developed the sig2 deletion mutant strain，named Δsig2, results showed that Δsig2 were more sensitive to heat and had significantly lower survivability than control group D. radiodurans wild type under the condition of high temperature（48℃）stress. We also analyzed the QRT-PCR results and verify that the deletion of sig2 contributed to positive or negative regulation of heat stress related genes in a degree. As a result，we speculated sig2 probably involved in the regulation of heat stress response.

Key words: Deinococcus radiodurans, &sigma, factor, Sig2, high temperature stress