莱茵衣藻鞭毛内运输蛋白IFT81调控鞭毛组装

利用插入突变的方式获得了一株衣藻不运动突变体ift81,该突变体表现出鞭毛缺失或者短鞭毛的性状。基因序列分析表明,外源基因aphⅧ插入了突变体中IFT81( intraflagellar transport, IFT)基因的第五个外显子内,并导致该外显子原有的52个碱基对被替换。把含有完整IFT81基因的重组质粒导入突变体ift81后,其鞭毛恢复为野生型且可以检测到IFT81-HA融合蛋白的表达,这证明突变体的鞭毛缺陷确实是由于IFT81基因突变所导致。电镜观察显示突变体中鞭毛的显微结构发生改变,免疫荧光实验证实IFT81蛋白主要定位于基体和鞭毛部位。上述结果表明：IFT81蛋白缺失会导致衣藻鞭毛组装缺陷,在鞭毛组装所需蛋白的运输过程中,IFT81蛋白是必不可少的。

Flagellar assembly in Chlamydomonas reinhardtii regulated by intraflagellar transport protein IFT81

A Chlamydomonas reinhardtii immobile mutant named ift81 was screened by insertional mutagenesis. The mutant was bald or with two short flagella. Gene sequencing confirmed that fifty-two base pairs in the fifth extron of IFT81 gene were replaced by the exogenous gene aphⅧ in the mutant. After a recombinant plasmid containing full IFT81 gene was imported into the mutant ift81, the phenotype of the mutant was rescued and the expression of IFT81-HA could be detected, which confirmed that the defect in IFT81 gene led to the abnormal flagella directly. Electron microscopy images exhibited the abnormal flagella of the mutant. An immunofluo-rescence assay revealed that IFT81 protein was localized to the basal body and flagella. This work shows that loss of protein IFT81 will directly lead to the defects of flagellar assembly, and IFT81 protein is indispensable for flagellar assembly in Chlamydomonas reinhardtii.