Sequence and expression of the mRNA encoding HSP22, the mitochondrial small heat-shock protein in pea leaves.
Sequence and expression of the mRNA encoding HSP22, the mitochondrial small heat-shock protein in pea leaves.
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DOI：
10.1042/bj3110805
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发表时间：
1995-11
期刊：
影响因子：
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通讯作者：
C. Lenne;M. Block;J. Garin;R. Douce
中科院分区：
文献类型：
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作者：
C. Lenne;M. Block;J. Garin;R. Douce
在40℃下对豌豆（Pisum sativum var. Douce Provence）植株进行3小时处理，可诱导线粒体基质室中产生和积累表观分子质量为22 kDa的小热休克蛋白，称为HSP22 [Lenne and Douce (1994) Plant Physiol. 105, 1255-1261]。我们在此表明，热应激豌豆植株中提取的mRNA经过体外翻译和免疫检测后，HSP22前体（即成熟蛋白加上传递肽）的表观分子质量为26 kDa。我们分离、克隆并测序了编码线粒体HSP22前体的全长cDNA。对线粒体HSP22的氨基酸序列分析表明，该蛋白是低分子质量热休克蛋白（HSP）超家族的代表成员，具有典型的小热休克蛋白的特定共识区域。最重要的是，将线粒体HSP22序列与叶绿体小HSPs序列进行比较，发现HSP22不包含典型的叶绿体共识区III。我们还分析了HSP22诱导的动力学，并报告了HSP22在转录水平上的时间表达结果。在温度升高至40℃高温后10 min内检测到HSP22 mRNA，即使豌豆植株继续进行热处理，HSP22 mRNA的表达量也明显下降。这些结果是根据先前发表的翻译数据进行讨论的[Lenne和Douce (1994) Plant Physiol. 105, 1255-1261]，特别是关于植物在热胁迫下线粒体的生理行为。此外，我们研究了HSP22积累与温度的依赖关系，并证明豌豆线粒体热休克反应仅在极端环境生长条件下发生。
A 3 h treatment at 40 degrees C of pea (Pisum sativum var. Douce Provence) plants induces production and accumulation of a small heat-shock protein of 22 kDa apparent molecular mass, designated HSP22, in the matrix compartment of mitochondria [Lenne and Douce (1994) Plant Physiol. 105, 1255-1261]. We show here that the HSP22 precursor (i.e. the mature protein plus the transit peptide) has an apparent molecular mass of 26 kDa after in vitro translation of mRNA extracted from heat-stressed pea plants and immunodetection. We have isolated, cloned and sequenced the full-length cDNA encoding the precursor of the mitochondrial HSP22. An analysis of the amino acid sequence of the mitochondrial HSP22 reveals that this protein is a representative member of the low-molecular-mass heat shock protein (HSP) superfamily, exhibiting the specific consensus regions that are typical of the small HSPs. Most importantly, comparison of the mitochondrial HSP22 sequence with that of chloroplast small HSPs indicates that HSP22 does not contain the typical chloroplast consensus region III. We have also analysed the kinetics of HSP22 induction, and report results on the temporal expression of HSP22 at the transcriptional level. HSP22 mRNA was detected as soon as 10 min after the temperature was raised to a high temperature of 40 degrees C. Then the amount of HSP22 mRNA declined considerably even though pea plants were still submitted to the heat treatment. These results are discussed in light of the translation data previously published [Lenne and Douce (1994) Plant Physiol. 105, 1255-1261], particularly concerning the physiological behaviour of mitochondria when plants are heat-stressed. Furthermore, we have studied the dependence of HSP22 accumulation with temperature and demonstrate that the pea mitochondrial heat-shock response is only developed under extreme environmental growth conditions.