Abstract:
Kinesins are eukaryotic microtubule motor proteins subdivided into conserved families with distinct functional roles. While many kinesin families are widespread in eukaryotes, each organismal lineage maintains a unique kinesin repertoire composed of many families with distinct numbers of genes. Previous genomic surveys indicated that land plant kinesin repertoires differ markedly from other eukaryotes. To determine when repertoires diverged during plant evolution, we performed robust phylogenomic analyses of kinesins in 24 representative plants, two algae, two animals, and one yeast. These analyses show that kinesin repertoires expand and contract coincident with major shifts in the biology of algae and land plants. One kinesin family and five subfamilies, each defined by unique domain architectures, emerged in the green algae. Four of those kinesin groups expanded in ancestors of modern land plants, while six other kinesin groups were lost in the ancestors of pollen-bearing plants. Expansions of different kinesin families and subfamilies occurred in moss and angiosperm lineages. Other kinesin families remained stable and did not expand throughout plant evolution. Collectively these data support a radiation of kinesin domain architectures in algae followed by differential positive and negative selection on kinesins families and subfamilies in different lineages of land plants.
摘要:
驱动蛋白是真核微管运动蛋白,细分为具有不同功能作用的保守家族。虽然许多驱动蛋白家族在真核生物中普遍存在,每个生物谱系都保持着一个独特的驱动蛋白库,由许多具有不同数量基因的家族组成。先前的基因组研究表明,陆地植物驱动蛋白库与其他真核生物明显不同。为了确定植物进化过程中库存物何时发散,我们在24个代表性植物中对驱动蛋白进行了强大的系统发育分析,两种藻类,两只动物,和一个酵母。这些分析表明,驱动蛋白库的扩展和收缩与藻类和陆地植物生物学的重大变化相吻合。一个驱动蛋白家族和五个亚家族,每个都由独特的域架构定义,出现在绿藻中。其中四个驱动蛋白群体在现代陆地植物的祖先中扩展,而其他六个驱动蛋白组则在带有花粉的植物的祖先中丢失。苔藓和被子植物谱系中发生了不同的驱动蛋白家族和亚家族的扩展。其他驱动蛋白家族保持稳定,并且在整个植物进化过程中没有扩展。总的来说,这些数据支持藻类中驱动蛋白结构域结构的辐射,然后对陆地植物不同谱系中的驱动蛋白家族和亚家族进行不同的正选择和负选择。