Chromosomal localization reveals three kinesin heavy chain genes in mouse

Kinesin-related proteins constitute a superfamily of microtubule-dependent motors that play important roles in organelle transport and cell division. These molecules share a conserved motor region of approximately 340 amino acids, which is attached to diverse "tail" or cargo-binding domains. The kinesin superfamily was first defined by kinesin heavy chain, which is the principal component of "true" kinesin. Invertebrates appear to possess only a single gene encoding kinesin heavy chain. Mammals appear to have two or more genes encoding kinesin heavy chain, although the precise situation has been unclear. Here we definitively demonstrate that mouse has three kinesin heavy chain genes, Kif5a, Kif5b, and Kif5c. Kif5a, Kif5b, and Kif5c map to mouse chromosomes 10, 18, and 2; Kif5a and Kif5c appear to be expressed only in neuronal tissues by Northern blot analysis while Kif5b appears to be ubiquitous in its expression.