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组蛋白H3与其他类型的组蛋白分子H2A, H2B, H4共同构成了真核生物核小体的八聚体核心。研究发现组蛋白H3的多种翻译修饰,如甲基化、乙酰化、磷酸化等在调控基因转录过程种发挥了重要的作用。本研究从盐胁迫处理的水稻幼苗组织中分离了一个新的水稻组蛋白H3基因RH3.2A,编码具有136个氨基酸残基的多肽,与多种植物的组蛋白H3蛋白具有高度的氨基酸一致性。多序列比较发现,除了基因结构差异之外,还有3个位置的氨基酸残基(32、88、91)在H3.1与H3.2型组蛋白H3中存在差异。研究了RH3.2A基因在高盐和ABA胁迫下的表达,结果发现在水稻根部RH3.2A基因受高盐的强烈诱导,而在叶片RH3.2A基因的表达则不受高盐诱导,此外RH3.2A基因也受外源ABA的诱导,结合启动子分析的结果,我们认为RH3.2A基因可能参与了依赖于ABA的高盐胁迫应答反应。文章讨论了植物组蛋白H3基因在高盐胁迫应答反应中可能的作用。
Histone H3 together with other types of histone molecules H2A, H2B, H4 constitute the octamer core of eukaryotic nucleosomes. It has been found that various translational modifications of histone H3, such as methylation, acetylation and phosphorylation, play an important role in the regulation of gene transcription. In this study, a new rice histone H3 gene RH3.2A was isolated from rice seedlings treated with salt stress and encoded a peptide with 136 amino acid residues, which was highly homologous to the histone H3 proteins of various plants . Multiple sequence comparisons revealed that in addition to the differences in gene structure, three more amino acid residues (32,88,91) differed between H3.1 and H3.2 histone H3. The expression of RH3.2A gene under high salt and ABA stress was studied. The results showed that the RH3.2A gene in rice roots strongly induced by high salt, while the expression of RH3.2A gene in leaves was not induced by high salt. In addition, .2A gene was also induced by exogenous ABA. Combined with the result of promoter analysis, we think that RH3.2A gene may be involved in ABA-dependent response to salt stress. The article discusses the possible role of plant histone H3 genes in response to salt stress.