小麦染色体配对基因Ph1结构剖析及调控机制研究进展  

Physical Structure and Regulating Mechanism of Ph1 Gene in Wheat

作　　者：张悦[1,2,3] 林志珊[2,3] 叶兴国[2,3] 辛志勇[2,3] 郭世华[1] 

机构地区：[1]内蒙古农业大学农学院,呼和浩特010018 [2]中国农业科学院作物科学研究所 [3]农业部作物遗传育种重点开放实验室,北京100081

出　　处：《科技导报》2009年第14期110-115,共6页Science & Technology Review

基　　金：国家自然科学基金项目(30571159);国家作物基因资源和基因改良重大科学工程项目

摘　　要：近年来,关于小麦抑制部分同源染色体配对基因Ph1的研究有了突破性进展。本文对该基因的结构和调控机理的最新研究进行综述。通过创造和分子标记鉴定Ph1缺失突变体,利用分子生物学及比较基因组学技术,该基因位点被界定于5BL上一个2.5Mb的区域内,含有一个类cdk基因簇,且在该类cdk基因簇中插入一个亚端粒异染色质片段。细胞学研究显示,Ph1基因通过控制亚端粒的互作启始染色体识别和配对伙伴选择。与此同时,生物信息学揭示,这些类cdk基因与人类和老鼠的cdk2基因高度同源,它们与细胞周期中DNA复制、染色质凝集、碱基错配修复等事件相关。减数分裂时,该基因位点通过"感知"染色体的同源性程度而触发染色质的构象变化,从而控制染色体的配对和重组。此外,小麦中可能存在一种与Ph1相关的类似于酵母中的粗线期检查点机制。预测未来的研究将可能集中在Ph1对染色体同源性的"感知"机制、Ph1的开启与关闭、植物减数分裂重组的忠实性及减数分裂过程的检查点机制等方面。The behavior of chromosome pairing in allohexaploid and tetraploid wheat is similar to that in diploid wheat, which is called the diploid-like chromosome pairing. As early as the 1950s, the key gene for chromosome pairing in wheat used to be called Phi and was known to be allocated on the long arm of chromosome 5BL. Complex as it is, in recent years, the studies on the structure and regulating mechanism of Phi gene have achieved breakthrough progresses. With the development of molecular biology and comparative genomics, the Phi locus has been defined more precisely on the chromosome 5BL of hexaploid wheat. Based on the newly created deletion lines, the locus is identified physically and allocated within a 2.5 Mb region. It is found that it contains a cdklike gene cluster, in which a segment of sub -telomerie heterochromatin is inserted. It is indicated by cytology that the Phl locus achieves chromosomes pairing partners＂ recognition and selection via controlling the interaction of sub-telomeric. Bioinformatics analysis reveals that the cdk-like genes are closely homologous to cdk2 from human and mouse, with respect to DNA replication, chromatin remodeling and mismatch repair events. The gene is involved in the initiation of chromatin remodeling at meiosis by sensing the level of homologues and enables the chromosomes to become competent to pair and recombine efficiently. Besides, it is postulated that a pachytene checkpoint similar to that in yeast,might be present in plants, as related to Phi. It is assumed that future studies on this topic will be focused on the mechanism of sensing chromosome homology, temporary switch on or switch off Phi, the fidelity of meiotic recombination and checkpoint on meiosis.

关 键 词：小麦 Ph1基因 结构剖析 作用机制 

分 类 号：S512.1[农业科学—作物学]