小立碗藓冷驯化相关基因Pp-LIM only A的克隆与表达

Isolation and Identification of a Pp-LIM only A Gene Expressed During Cold Acclimation in Physcomitrella patens

摘要:

植物经历冷驯化后抗冻能力会有所提高。利用cDNA-AFLP方法从经过0oC冷驯化处理的小立碗藓中筛选到差异表达的Pp-LIM only A基因片段。cDNA和基因序列比较分析表明此基因含有7个内含子和8个外显子, 编码由345个氨基酸残基组成的蛋白质, 其中只含有一个LIM结构域, 与动物蛋白质PDZ/LIM家族有很高的同源性, 推测是一种新的植物LIM蛋白。实时定量PCR分析显示其在冷驯化6 h后表达量即开始明显增加, 并随着冷驯化时间的延长表达量大幅度提高。Pp-LIM only A蛋白可能通过LIM结构域对细胞骨架的作用而影响了细胞膜的稳定性, 本研究对其在抗冻中的作用作了进一步讨论。

Abstract:

Cold acclimation can improve freezing tolerance. Here cDNA amplified fragment length polymorphism (cDNA-AFLP) was used to isolate differentially expressed cDNAs and a Pp-LIM only A cDNA was isolated and identified in the cold acclimation of Physcomitrella patens. Real-time RT-PCR indicated it is obviously up-regulated at 6 h, 12 h, 24 h, 48 h and 72 h after cold acclimation. After comparing the cDNA with the gene sequence, seven introns and eight exons were identified in the cDNA. The cDNA putatively encodes a protein of 345 amino acid residues and only contains one LIM domain which has highly similarity with the PDZ/LIM domains of the protein family in animals. We proposed that Pp-LIM only A be a new gene coding for the LIM-domain containing protein and enhance stability of cell membrane via their effects on cytoskeleton during cold acclimation in P. patens.