Amplification of prolamin storage protein genes in different subfamilies of the Poaceae
Amplification of prolamin storage protein genes in different subfamilies of the Poaceae
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DOI：
10.1007/s00122-009-1143-x
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发表时间：
2009-08
影响因子：
5.4
通讯作者：
Jian-Hong Xu;J. Messing
中科院分区：
文献类型：
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作者：
Jian-Hong Xu;J. Messing
醇溶谷蛋白是谷物中的种子贮藏蛋白，是饲料和食品必需氨基酸的重要来源。编码这些蛋白质的基因由分散和串联扩增产生。虽然以前的研究集中在不同草种的蛋白质序列上，但我们现在可以通过询问它们的基因如何被祖先共享并在同一物种家族的不同谱系中复制来为它们的关系添加一个新的视角。这些差异来源于染色体区域的比对，其中共线性用于鉴定同线位置中的醇溶谷蛋白基因，也称为直链基因拷贝。新的或旁系同源的基因拷贝被插入到相同基因组的串联或新的位置。更重要的是，人们可以检测到旧基因的丢失。我们分析了来自水稻、高粱、小麦、大麦和短柄草的含有醇溶蛋白基因的染色体间隔，这些基因代表禾本科的不同亚科。Poaceae通常被称为禾本科，包括三个主要的亚科，Ehrhartoideae（水稻），Pooideae（小麦，大麦和短柄草）和Panicoideae（小米，玉米，高粱和柳枝稷）。基于染色体位置和序列差异，推断基因扩增事件的顺序变得可能。此外，不同亚科中较老基因的丢失似乎允许旁系同源基因的分化速度更快。蛋白质结构的变化影响其物理性质、亚细胞位置和氨基酸组成。另一方面，新基因拷贝的调控序列元件和相应的转录激活因子比编码序列更保守，与这些基因的组织特异性表达一致。
Prolamins are seed storage proteins in cereals and represent an important source of essential amino acids for feed and food. Genes encoding these proteins resulted from dispersed and tandem amplification. While previous studies have concentrated on protein sequences from different grass species, we now can add a new perspective to their relationships by asking how their genes are shared by ancestry and copied in different lineages of the same family of species. These differences are derived from alignment of chromosomal regions, where collinearity is used to identify prolamin genes in syntenic positions, also called orthologous gene copies. New or paralogous gene copies are inserted in tandem or new locations of the same genome. More importantly, one can detect the loss of older genes. We analyzed chromosomal intervals containing prolamin genes from rice, sorghum, wheat, barley, andBrachypodium, representing different subfamilies of thePoaceae. ThePoaceaecommonly known as the grasses includes three major subfamilies, theEhrhartoideae(rice),Pooideae(wheat, barley, andBrachypodium), andPanicoideae(millets, maize, sorghum, and switchgrass). Based on chromosomal position and sequence divergence, it becomes possible to infer the order of gene amplification events. Furthermore, the loss of older genes in different subfamilies seems to permit a faster pace of divergence of paralogous genes. Change in protein structure affects their physical properties, subcellular location, and amino acid composition. On the other hand, regulatory sequence elements and corresponding transcriptional activators of new gene copies are more conserved than coding sequences, consistent with the tissue-specific expression of these genes.