Kinesin-II is not essential for mitosis and cell growth in Chlamydomonas

The FLA10 gene product (Fla10p) in Chlamydomonas, a heterotrimeric kinesin-II, plays a crucial role in flagellar assembly as a motor protein driving intraflagellar transport. This protein has also been suggested to play a role in mitosis based on its localization to mitotic spindle. A role for Fla10p in mitosis has been difficult to test because to date only conditional (temperature-sensitive) mutant alleles were available, and it is not known whether these retain residual function for mitosis at the non-permissive temperature. In this report, we describe a null allele of fla10 produced by insertional mutagenesis. This mutant does not assemble flagella, but proliferates at a rate identical to that of wild type cells. Observation of microtubule organization in the cell body revealed that normal mitotic spindles are formed in dividing mutant cells. Thus, we conclude that FLA10 kinesin plays no significant roles in mitosis.