Dutcher S K, Trabuco E C
Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Boulder, Colorado 80309-0347, USA.
Mol Biol Cell. 1998 Jun;9(6):1293-308. doi: 10.1091/mbc.9.6.1293.
We have cloned the UNI3 gene in Chlamydomonas and find that it encodes a new member of the tubulin superfamily. Although Uni3p shares significant sequence identity with alpha-, beta-, and gamma-tubulins, there is a region of Uni3p that has no similarity to tubulins or other known proteins. Mutant uni3-1 cells assemble zero, one, or two flagella. Pedigree analysis suggests that flagellar number in uni3-1 cells is a function of the age of the cell. The uniflagellate uni3-1 cells show a positional phenotype; the basal body opposite the eyespot templates the single flagellum. A percentage of uni3-1 cells also fail to orient the cleavage furrow properly, and basal bodies have been implicated in the placement of cleavage furrows in Chlamydomonas. Finally when uni3-1 cells are observed by electron microscopy, doublet rather than triplet microtubules are observed at the proximal end of the basal bodies. We propose that the Uni3 tubulin is involved in both the function and cell cycle-dependent maturation of basal bodies/centrioles.
我们已在衣藻中克隆出 UNI3 基因，发现它编码微管蛋白超家族的一个新成员。尽管 Uni3p 与α-、β-和γ-微管蛋白有显著的序列同源性，但 Uni3p 有一个区域与微管蛋白或其他已知蛋白质没有相似性。突变体 uni3-1 细胞组装出零根、一根或两根鞭毛。谱系分析表明，uni3-1 细胞中的鞭毛数量是细胞年龄的函数。单鞭毛的 uni3-1 细胞表现出位置表型；与眼点相对的基体形成单根鞭毛。一定比例的 uni3-1 细胞也不能正确定向分裂沟，并且基体与衣藻中分裂沟的定位有关。最后，当通过电子显微镜观察 uni3-1 细胞时，在基体近端观察到的是双联体而非三联体微管。我们提出，Uni3 微管蛋白参与基体/中心粒的功能以及细胞周期依赖性成熟过程。
