南极适冷菌Psychrobacter sp.G普遍胁迫蛋白(USP)基因的克隆及其胁迫条件下的应答特征分析  

Cloning and Characteristic Analysis of Universal Stress Protein(USP) Gene of Antarctic Bacterium Psychrobacter sp.G in Response to Stress Treatments

作　　者：宋维志[1,2] 林学政[1,2] 车帅[1,2] 

机构地区：[1]国家海洋局第一海洋研究所,山东青岛266061 [2]国家海洋局海洋生物活性物质重点实验室,山东青岛266061

出　　处：《海洋科学进展》2013年第1期145-152,共8页Advances in Marine Science

基　　金：国家自然科学基金--南极适冷菌Psychrobacter sp.G温度与盐度胁迫下基因表达谱分析及冷/热基因应答机制研究(41176174)

摘　　要：根据南极适冷菌Psychrobacter sp.G基因组测序草图发现并克隆到了1个普遍胁迫蛋白(Universal StressProtein,USP)基因Usp1141。该基因ORF长462bp,编码153个氨基酸,蛋白理论分子量为17kDa,pI为5.23。通过多序列比对发现该USP含有交替排列的4个α螺旋和5个β折叠,以及与ATP结合相关的氨基酸残基,表明该蛋白可能通过与ATP结合而发挥作用。利用实时定量PCR技术对该蛋白在不同胁迫条件下的表达情况进行分析发现,温度变化对Usp1141基因的表达没有显著影响;低盐度(0,15)胁迫会显著抑制其表达,而高盐度(90,120)胁迫则会显著促进其表达;在温度与盐度协同胁迫条件下,当培养基盐度低于菌株生长的最适盐度时,无论温度高低,Usp1141基因的表达均受到抑制,而当培养基盐度高于最适盐度时,无论温度高低,Usp1141基因的表达均会提高。实时定量PCR研究表明,Usp1141基因可能在南极适冷菌Psychrobactersp.G对环境渗透压变化的适应性中发挥作用。A universal stress protein gene, designated as Usp1141, was cloned from the Antarctic psychro- trophic bacterium Psychrobacter sp. G according to its genomic draft. The ORF of Uspll41 gene was 462 bp in length and encoded a protein consisting of 153 amino acid residues with a molecular mass of 17 kDa and a calculated pI of 5. 23. Multiple sequences alignment revealed that four a-helices and five 13-sheets were alternately arranged in its secondary structure. Several conserved amino acid residues related with ATP combination were identified, qRT-PCR analysis showed that the expression of Usp1141 gene was not significantly affected by temperature shift, but it was obviously inhibited by low salinity （0, 15）, and remarkably enhanced by high salinity （90, 120）. The results under the combined temperature and salinity stress were consistent with that of salinity stress only, indicating that Usp1141 gene of Psychrobacter sp. G might be involved in the adaptation of the environmental osmotic fluctuation.

关 键 词：适冷杆菌 普遍胁迫蛋白 应激反应 表达分析 

分 类 号：Q751[生物学—分子生物学]