[Cloning and expression of Gymnadenia conopsea GcSec61beta gene encoding endosplasmic reticulum membrane translocation channel protein]

Protein translocation channel in endosplasmic reticulum (ER) of eukaryotes is composed of several subunits of Sec61 complex, which is essential for protein secretion. In the present study, we cloned a full-length cDNA fragment of 621 bp coding 107 amino acids from a psychrophile and endangered plant Gymnadenia conopsea, which grows in high land. Sequence analysis revealed that the gene was highly homologous to the member Sec61beta of ER protein transporter channel, which was thus designated as GcSec61beta. Phylogenetic tree shows that the GcSec61beta was closely related to the corresponding genes from Arabidopsis thaliana and Oryza sativa. Results of semi-quantitative RT-PCR showed that the expression of GcSec61beta was high both in leaves and the bud, and also induced by low temperature treatment. The sequence of the GcSec61beta was introduced into pET28a vector and transformed to E. coli strain BL21. The growth of E. coli was slowed down but the cold resistance was increased by the expression of GcSec61beta, which provides a new function of GcSec61beta protein.