Molecular cloning and functional analysis of mouse C-terminal kinesin motor KifC3

Proteins of the kinesin superfamily define a class of microtubule-dependent motors that play crucial roles in cell division and intracellular transpor t. To study the molecular mechanism of intracellular transport involving mi crotubule-dependent motors, a cDNA encoding a new kinesin-like protein call ed KifC3 was cloned from a mouse brain cDNA library. Sequence and secondary structure analysis revealed that KifC3 is a member of the C-terminal motor family. In contrast to other mouse C-terminal motors, KifC3 is apparently ubiquitous and may have a general role in intracellular transport. To under stand the in vivo function of the KifC3 gene, we used homologous recombinat ion in embryonic stem cells to construct knockout mouse strains for the Kif C3 gene. Homozygous mutants of the KifC3 gene are viable, reproduce normall y, and apparently develop normally. These results suggest that KifC3 is dis pensable for normal development and reproduction in the mouse.