紫茎泽兰细胞质小热激蛋白HSP17.7基因的cDNA克隆与表达

Gene cloning and expression of a cytosolic small heat shock protein gene(HSP17.7) from Ageratina adenophora

利用RT-PCR和RACE-PCR技术,从热激处理的紫茎泽兰叶片总RNA中扩增出了细胞质小分子量热激蛋白(sHSP)全长683 bp的cDNA基因序列。在GeneBank上的登录号是EF105483。通过半定量分析,HSP17.7基因编码的热激蛋白在常温下有表达,且叶、茎中的表达量比根中的高;在热激(40℃)和冷处理(4℃)的情况下,根、茎、叶中的表达量均有增加。为研究基因在温度胁迫下的功能,将HSP17.7基因在大肠杆菌中表达。在细胞致死温度(50℃)下,HSP17.7能够改善细胞死亡的现象;4℃条件下,也得到相同结果。这些结果表明,HSP17.7可能在紫茎泽兰耐温度胁迫中发挥作用。

Cytoplasmic classI sHSP cDNA with full length of 683 bp was cloned from heat-shocked leaves of Crofton weed （Ageratina adenophora ） by conducting RT-PCR and RACE-PCR. The accession number is EF105483 in the GeneBank. The semi-quantitative RT-PCR results revealed that the gene HSP17.7 could be detected and expressed significantly different between organ tissues at normal temperature. The transcription of HSP17.7 in leaves and stems was higher than that in roots. The expression of HSP17.7 significantly increased under heat treatment and chilling treatment in all root, stem and leaf tissues. To verify its possible function under heat and chilling stress, recombinant HSP17.7 was overexpressed in Escherichia coli. After the temperature being transferred from 37℃ to 50℃, which was known to cause cell autolysis, those cells with accumulated HSP17.7 exhibited improved viability compared with control. Similar results were observed under chilling treatment at 4 ℃ as well. Overall, the results indicate that sHSP of Crofton weed is positively involved in the responses to heat and chilling stress.