耐辐射异常球菌高温胁迫下双组份系统dtrAB基因的功能分析

分析预测了耐辐射异常球菌(Deinococcus radiodurans)基因组中的一对双组份蛋白DtrA(DR_A0009)和DtrB(DR_A0010)。生物学软件分析结果显示,DtrA含有组氨酸激酶(HisKA_3)结构域和ATP酶(HATPase_c)结构域,且有4个跨膜区;DtrB含有接收结构域和HTH结构域,且有Lux家族的调控蛋白。两者共同构成一个转录单元。分别构建了dtrA和dtrB基因缺失突变株(ΔdtrA和ΔdtrB),发现42℃高温胁迫条件下,2个突变株的生长和生存率明显低于野生型菌株,而正常培养温度(30°C)条件下,突变株和野生型菌株的生长无差异。QRT-PCR分析显示,dtrA或dtrB基因突变导致了热激相关基因发生下调。推测双组份蛋白DtrAB参与了耐辐射异常球菌在高温胁迫下的调控作用。

Functional Analysis of the Two\|component System dtrAB Genes in Response to High Temperature in Deinococcus radiodurans

A putative two component system DtrA and DtrB encoded by DR_A0009 and DR_A0010 was found in D.radiodurans. DtrA contains the histidine kinase, HisKA_3 domain and HATPase_c domain, containing four transmembrane regions; DtrB relates to LuxR\|family, and contains response regulator domain and HTH domain. The two genes were organized into an operon. Construction of D. radiodurans R1 mutants deleted dtrAB gene(ΔdtrA and ΔdtrB）by means of Kan cassette insertion. We found that the phenotype and growth curves of the two mutants were more sensitive than the wild\|type R1 under high temperature(42℃), while there are no difference between the two mutants and the wild\|type R1 under optimal temperature(30℃). Using QRT\|PCR to analysis the relative expression of heat shock genes, the results showed that heat shock genes were down\|regulated in the two mutants. That indicated two system component system DtrA and DtrB plays an important role in heat resistance.