四翅滨藜AcDHN基因的克隆及其抗逆功能分析

脱水素（dehydrin，DHN）是一类胚胎发育后期丰富蛋白（LEA），在植物脱水条件下能保护细胞内蛋白质和膜结构免受破坏。本研究中，从四翅滨藜（Atriplex canescens）cDNA文库克隆得到逆境胁迫相关蛋白基因AcDHN的全长cDNA（登录号：JN974246），并进行序列分析。将4cD鼢别插入到原核表达载体pET28a和双元表达载体pYES-DEST52中，通过转化大肠杆菌和酿酒酵母进行原核表达分析和真核表达分析。结果表明：AcDHN序列全长为1408bp，完整的开放阅读框长为1017bp，由338个氨基酸残基组成，预测蛋白质分子量为38.3kDa，理论等电点为6．47，AcDHN与仙人掌中DHN蛋白同源性为55％。AcDHN基因在大肠杆菌BL21（DE3）中诱导表达出分子质量约45．2kDa的融合蛋白。重组酵母菌株能表现出艮好抗逆性，特别是对NaCl、低温、Na2CO3和NaHCO3胁迫的抗逆性，其中抗碱胁迫能力表现最强。

Cloning and Stress Risistance Functional Characterization of an AcDHN Gene from Atriplex canescens

Dehydrin （DHN） present a distinct biochemical group of late embryogenesis abundant （LEA） proteins. It is proposed that dehydrins can protect proteins and cell membranes against unfavourable structure changes caused by dehydration in the plant cells. In this research, the full sequence of cDNA sequence of AcDHN gene was cloned from Atriplex canescens. The accession number of AcDHN in GenBank was JN974246. The AcDHN gene was introduced into the prokaryotic expression vector pET28a and the binary vector pYES-DEST52, and transformed into Escherichia coli BL21 （DE3） and Saccharomyces cerevisiae INVScl, respectively. The results revealed that： the full sequence of AcDHN is 1 408 bp in length and contains an open reading frame （ORF） of 1 017 bp, encoding a protein of 338 amino acid residues, with protein molecular weight of 38.3 kDa and PI 6.47. The AcDHN had 55% amino acid sequence homology to the sequence of DHN from Opuntia streptacantha. AcDHN was expressed its fusion protein （about 45.2 kDa） in E. coli BL21 （DE3）. The recombinant yeast cells have a higher stress resistance than control cells, especially exhibit the capability to cope with the NaCl, low temperature, NaCO3 and NaHCO3, and the tolerance to the stress of alkali is the most highly.