热激信号转导中的钙-钙调素途径

doi:10.3321/j.issn:1000-7091.2003.z1.007

摘要/Abstract

摘要： 大量证据证明钙-钙调素(Ca²⁺CaM)信号系统参与植物的热激信号转导。用激光共聚焦扫描显微镜研究小麦胞内Ca²⁺浓度的变化,37℃热激可引起小麦胞内自由Ca²⁺浓度的迅速提高。在Ca²⁺存在条件下,热激也引起小麦CaM基因CaM1-2的表达及细胞内CaM蛋白含量的提高。用CaCl2处理小麦幼苗明显提高小麦热激基因hsp26和hsp70的表达和热激蛋白的合成,而Ca²⁺的螯合剂EGTA,Ca²⁺通道阻断剂异博定和LaCl₃、CaM抑制剂W7、TFP和CPZ明显降低了热激基因hsp26和hsp70的表达和热激蛋白的合成。EGTA、易博定、TFP或CPZ的处理也阻止小麦耐热性的获得。小麦CaM基因与热激基因的表达动力学研究表明CaM位于热激信号转导的上游,而Ca²⁺是热激启动的胞内关键因子。凝胶阻滞分析提出Ca²⁺CaM在热激信号转导中的作用是通过激活热激转录因子的DNA结合活性来实现的。提出在植物细胞内存在一条新的热激信号转导途径:钙-钙调素途径。

关键词: 钙离子, 钙调素, 热激蛋白, 热激转录因子, 信号转导

Abstract: Laboratory studies by the author show ed the involvement of calcium and calciumactivatedcalmodulin.(Ca²⁺-CaM) in heat shock.HS) signal transduction..sing Fluo3/ AM and Laser Scanning Confocal Microscopy,it was found that the increase of int racellular free calcium ion concent ration started within.minafter.37 HS in.heat.The levels of CaM mRNA and protein increased during HS at 37 in the presenceof Ca²⁺.The expression of hsp26 and hsp70 genes,synthesis of heat shock proteins were upregulated by addition of CaCl2,and dow nregulated by the Ca²⁺ chelator EGTA,the Ca²⁺ channel blockers LaCl3 and verapamil,or the CaM antagonists W7,CPZ and TFP. The acquired thermotolerance developed by HS at 37 was eliminated by treatment with EGTA,verapamil,CPZ and TFP. The temporal ex pression of the CaM1-2gene,and the hsp26 and hsp70 genes,demonst rated that CaM is located upstream in HS signal transduction,and Ca²⁺ is the key factor turning on HS signal transduction pathw ay. The result sobtained by gel mobility shift assaydemonst rated that Ca²⁺ CaM is involved in HS signal transduction by regulat ing DNAbinding activity of HStranscription factor. Based on above findings,.new pathw ay,Ca²⁺ CaM pathw ay of HS signal transduction,was proposed.

Key words: Calcium ion, Calmodulin, Heat shock proteins, Heat shock t ranscript ion factor, Signal transduction

中图分类号:

S51.01??

ZHOU Ren-gang. Ca²⁺CaM Pathway of Heat Shock Signal Transduction[J]. ACTA AGRICULTURAE BOREALI-SINICA, doi: 10.3321/j.issn:1000-7091.2003.z1.007.

http://www.hbnxb.net/CN/Y2003/V18/IS1/24

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