禾谷类植物胚凝集素基因的分子起源与进化  

Molecular Origin and Evolution of Germ Lectin Gene in Cereals

作　　者：刘庆法[1] 郝峥嵘[1] 曲志才[1] 陈永青[1] 沈大棱[1] 

机构地区：[1]复旦大学生命科学学院遗传学研究所

出　　处：《复旦学报（自然科学版）》2001年第5期530-534,共5页Journal of Fudan University：Natural Science

基　　金：上海市科委科学与技术发展基金资助项目(953907009)

摘　　要：对禾谷类植物胚凝集素的基因结构进行了详细分析，发现该基因有４个ｈｅｖｅｉｎ　（结合　域）编码区．研究表明，禾谷类植物胚凝集素基因是由１个较小的带单个ｈｅｖｅ　ｉｎ的祖先基因（或片段）经过２次顺接重复产生的．第一次重复产生１个双ｈｅｖｅｉｎ结　构，然后以这个双ｈｅｖｅｉｎ结构为单位再次发生重复，最终产生了具有４个ｈｅｖ　ｅｉｎ的禾谷类胚凝集素基因的原型．对４２个不同来源的ｈｅｖｅｉｎ　ＤＮＡ序列进化关系的研究进一步　证实了上述结论．　初步发现，小麦Ｂ组染色体编码的麦胚凝集素ＷＧＡ－Ｂ基因可能是该　类禾谷类凝集素基因中比较原始的类型．植物ｈｅｖｅｉｎ的氨基酸通式可以表述为：　ＣＸＸXXCCSXXGXCGXXXXXC.A detailed sequence dissection and multiple comparison of the domain-coding reg ions clearly showed that cereal germ lectin genes were evolved from a small ance stral gene (or a small truncated fragment) by two duplications, which resulted i n the modern form with four tandem-duplicated highly-homologous chitin-bindin g domains. The first duplication produced a double hevein structure. Then the do uble hevein structure duplicated further and resulted in a tetra-hevein germ le ctin gene, which diversified further in each cereal species. Germ lectin gene encoded by genome B of wheat (WGA-B) was presumed as the anc ient form of germ lectin gene. The conserved amino acid sequence of heveins in plants was inferred as CXXXXCCSXXGXCGXXXXXC.

关 键 词：胚凝集素 禾谷类 结合域 基因结构分析 结合糖蛋白 分子起源 进化机制 

分 类 号：Q946.1[生物学—植物学] Q943.2