TGFb-like Signaling and Spicule Development n Caenorhabditis elegans

A TGFb-like signal is required for spicule development in Caenorhabditis elegans males. This signal appears to originate in the male-specific musculature and is required for the migrations of cells within the proctodeum. The migrations of these cells form cellular molds, the spicule traces, in which the cuticle of the spicules is secreted. Mutations in daf-4, sma-2, sma-3, and sma-4, which disrupt TGFb-like signaling, result in aberrant migrations and morphologically abnormal spicules. af-4, and hence the TGFb-like signal, is required prior to or during cell migrations. Therefore, the TGFb-like signal may ct to prime the migrating cells or as a guidance cue. Mutations in lin-31 result in identical cell migration and spicule orphology defects. Thus, lin-31, which encodes a “winged helix” protein (Miller et al., Genes Dev. 7, 933–947, 1993), may be a component of this TGFb-like signaling pathway. © 1999 Academic Press