Members of the kinesin II family are thought to play essential roles in man
y types of intracellular transport. One distinguishing feature of kinesin I
I is that it generally contains two different motor subunits from the Kif3
family. Three Kif3 family members (Kif3A, Kif3B, and Kif3C) have been ident
ified and characterized in mice. Intracellular localization and biochemical
studies previously suggested that Kif3C is an anterograde motor involved i
n anterograde axonal transport. To understand the in vivo function of the K
if3C gene, we used homologous recombination in embryonic stem cells to cons
truct two different knockout mouse strains for the Kif3C gene. Both homozyg
ous Kif3C mutants are viable, reproduce normally, and apparently develop no
rmally. These results suggest that Kif3C is dispensable for normal neural d
evelopment and behavior in the mouse.