Mechanisms controlling sex myoblast migration in Caenorhabditis elegans hermaphrodites.
Sex myoblast migration in C. elegans hermaphrodites is controlled by multiple guidance mechanisms. A gonad-dependent attraction functions to guide the sex myoblasts to their precise final positions flanking the gonad. In the absence of this attraction, a gonad-dependent repulsion is revealed. In addition to gonad-dependent influences, a gonad-independent mechanism propels the sex myoblasts anteriorly to a broad range of positions near the center of the animal. Here we describe a temporal analysis of sex myoblast migration that reveals when the gonad-dependent attraction and the gonad-independent mechanisms normally function. We provide evidence that EGL-17, a fibroblast growth factor-like protein, is expressed in the gonadal cells required to attract the sex myoblasts to their precise final positions, further supporting our model that EGL-17 defines the gonad-dependent attractant. Furthermore, cell ablation experiments reveal that EGL-17 and the gonad-dependent repellent likely emanate from the same cellular sources. Analyses of candidate mutations for their effects on the gonad-dependent repulsion reveal that a set of genes known to affect multiple aspects of axonogenesis, unc-14, unc-33, unc-44, and unc-51, is essential for this repulsive mechanism. In addition, we have discovered that a SAX-3/Roundabout-dependent mechanism is used to maintain the sex myoblasts along the ventral muscle quadrants.
Branda
C S
CS
Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06520-8005, USA.
Stern
M J
MJ
D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins; D002465:Cell Movement / Q000502:physiology*; D012734:Disorders of Sex Development; D005346:Fibroblast Growth Factors / Q000502:physiology; D006066:Gonads / Q000166:cytology*; D006133:Growth Substances / Q000502:physiology; D015801:Helminth Proteins / Q000502:physiology; D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D011971:Receptors, Immunologic / Q000502:physiology; D000097905:Roundabout Proteins
D029742:Caenorhabditis elegans Proteins; D005346:Fibroblast Growth Factors; D006133:Growth Substances; D015801:Helminth Proteins; D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D011971:Receptors, Immunologic; D000097905:Roundabout Proteins; C105157:Egl-17 protein, C elegans