RESUMO
The sex myoblasts (SMs) in C. elegans hermaphrodites undergo anteriorly directed cell migrations that allow for the proper localization of the egg-laying muscles. These migrations are controlled in part by a signal emanating from gonadal cells that allows the SMs to be attracted to their precise final positions flanking the center of the gonad. Mutations in egl-15 alter the nature of the interaction between the gonad and the SMs, resulting in the posterior displacement of the SMs. Here we show that egl-15 encodes a receptor tyrosine kinase of the fibroblast growth factor receptor (FGFR) subfamily with multiple roles in development. Three genes were identified that behave genetically as activators or mediators of egl-15 activity. One of these genes, sem-5, encodes an adaptor molecule that transduces signals from a variety of receptor tyrosine kinases. Like egl-15 and sem-5, the other two genes may similarly act in FGFR signaling pathways in C. elegans.
Assuntos
Caenorhabditis/citologia , Músculos/citologia , Receptores de Fatores de Crescimento de Fibroblastos/genética , Transdução de Sinais/fisiologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Movimento Celular/fisiologia , Transtornos do Desenvolvimento Sexual/fisiopatologia , Genes de Helmintos/fisiologia , Dados de Sequência Molecular , Músculos/fisiologia , Proteínas Tirosina Quinases/genética , Fatores Sexuais , Supressão GenéticaRESUMO
The development of the nematode Caenorhabditis elegans is known to depend extensively on reproducible cell-cell interactions. The analysis of many of these signaling events has revealed that, in most cases, the mechanisms that mediate them have been conserved throughout metazoan evolution. Thus, the analysis of signaling pathways in C. elegans can aid in the understanding of signal transduction mechanisms in general. In this review we focus on signaling events that occur during the development of the hermaphrodite egg-laying system. Many of these signaling events occur at approximately the same time and in very close proximity to one another. Following a brief review of the individual signaling systems employed, we analyze the data that have started to address how the specificity among these pathways is maintained and how multiple pathways that affect individual developmental decisions are integrated. These issues are common to all signaling systems and should be instructive in presenting the complexities that are involved in obtaining a global understanding of development.
