G proteins are required for spatial orientation of early cell cleavages in C. elegans embryos.
Heterotrimeric G proteins are signal-transducing molecules activated by seven transmembrane domain receptors. In C. elegans, gpb-1 encodes the sole Gbeta subunit; therefore, its inactivation should affect all heterotrimeric G protein signaling. When maternal but no zygotic gpb-1 protein (GPB-1) is present, development proceeds until the first larval stage, but these larvae show little muscle activity and die soon after hatching. When, however, the maternal contribution of GPB-1 is also reduced, spindle orientations in early cell divisions are randomized. Cell positions in these embryos are consequently abnormal, and the embryos die with the normal number of cells and well-differentiated but abnormally distributed tissues. These results indicate that maternal G proteins are important for orientation of early cell division axes, possibly by coupling a membrane signal to centrosome position.
Zwaal
R R
RR
The Netherlands Cancer Institute, Division of Molecular Biology, Amsterdam, The Netherlands.
Ahringer
J
J
van Luenen
H G
HG
Rushforth
A
A
Anderson
P
P
Plasterk
R H
RH
D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D001522:Behavior, Animal / Q000502:physiology; D017173:Caenorhabditis elegans / Q000196:embryology*; D002451:Cell Compartmentation; D002455:Cell Division; D002462:Cell Membrane / Q000378:metabolism; D002970:Cleavage Stage, Ovum; D017931:DNA Primers / Q000737:chemistry; D019084:Fluorescent Antibody Technique, Indirect; D019204:GTP-Binding Proteins / Q000502:physiology*; D015801:Helminth Proteins / Q000502:physiology; D008969:Molecular Sequence Data; D009024:Morphogenesis; D015398:Signal Transduction; D008941:Spindle Apparatus / Q000648:ultrastructure; D015053:Zygote / Q000502:physiology
D017931:DNA Primers; D015801:Helminth Proteins; D019204:GTP-Binding Proteins