A FAMILY OF UNCONVENTIONAL MYOSINS FROM THE NEMATODE CAENORHABDITIS-ELEGANS

The unconventional myosins are a superfamily of actin-based motor prot eins that are expressed in a wide range of cell types and organisms. T hirteen classes of unconventional myosin have been defined, and curren t efforts are focused on elucidating their individual functions in viv o. Here, we report the identification of a family of unconventional my osin genes in Caenorhabditis elegans. The hum-1, hum-2, hum-3 and hum- 6 (heavy chain of an unconventional myosin) genes encode members of my osin classes I, V, VI and VII, respectively. The hum-4 gene encodes a high molecular mass myosin (ca 307 kDa) that is one of the most highly divergent myosins, and is the founding and only known member of class XII. The physical position of each hurst gene has been determined. Th e hum-1, hum-2 and hum-3 genes have been mapped by extrapolation near previously uncharacterized mutations, several of which are lethal, ide ntifying potentially essential unconventional myosin genes in C. elega ns. (C) 1997 Academic Press Limited.