2 KINESIN LIGHT-CHAIN GENES IN MICE - IDENTIFICATION AND CHARACTERIZATION OF THE ENCODED PROTEINS

Native kinesin consists of two light chains and two heavy chains in a 1:1 stoichiometric ratio. To date, only one gene for kinesin light cha in has been characterized, while a second gene was identified in a gen omic sequencing study but not analyzed biochemically, Here we describe new genes encoding kinesin light chains in mouse. One of these light chains is neuronally enriched, while another shows ubiquitous expressi on. The presence of multiple kinesin light chain genes in mice is espe cially interesting, since there are two kinesin heavy chain genes in h umans (Niclas, J., Navone, F,, HomBooher, N,, and Vale, R, D. (1994) N euron 12, 1059-1072), To assess the selectivity of kinesin light chain interaction with the heavy chains, we performed immunoprecipitation e xperiments. The data suggested that the light chains form homodimers w ith no specificity in their interaction with the two heavy chains. Imm unofluorescence and biochemical subfractionation suggested differences in the subcellular localization of the two kinesin light chain gene p roducts. Although both kinesin light chains are distributed throughout the central and peripheral nervous systems, there is enrichment of on e in sciatic nerve axons, while the other shows elevated levels in olf actory bulb glomeruli, These results indicate that the mammalian nervo us system contains multiple kinesin light chain gene products with pot entially distinct functions.