Embryonic handedness choice in C. elegans involves the Galpha protein GPA-16.
The mechanism by which polarity of the left-right (LR) axis is initially established with the correct handedness is not understood for any embryo. C. elegans embryos exhibit LR asymmetry with an invariant handedness that is first apparent at the six-cell stage and persists throughout development. We show here that a strong loss-of-function mutation in a gene originally designated spn-1 affects early spindle orientations and results in near randomization of handedness choice. This mutation interacts genetically with mutations in three par genes that encode localized cortical components. We show that the spn-1 gene encodes the Galpha protein GPA-16, which appears to be required for centrosomal association of a Gbeta protein. We will henceforth refer to this gene as gpa-16. These results demonstrate for the first time involvement of heterotrimeric G proteins in establishment of embryonic LR asymmetry and suggest how they might act.
Bergmann
Dominique C
DC
Department of MCD Biology, University of Colorado, Boulder, CO 80309, USA.
Lee
Monica
M
Robertson
Barbara
B
Tsou
Meng-Fu B
MF
Rose
Lesilee S
LS
Wood
William B
WB
D000818:Animals; D019521:Body Patterning; D017173:Caenorhabditis elegans / Q000033:anatomy & histology / Q000196:embryology* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D019070:Cell Lineage; D016764:Cell Polarity; D018385:Centrosome / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D044385:GTP-Binding Protein alpha Subunits / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism; D018628:Gene Dosage; D005816:Genetic Complementation Test; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases; D034622:RNA Interference; D008941:Spindle Apparatus / Q000378:metabolism; D013696:Temperature
D029742:Caenorhabditis elegans Proteins; D004268:DNA-Binding Proteins; D044385:GTP-Binding Protein alpha Subunits; C097238:PAR-3 protein, C elegans; D017346:Protein Serine-Threonine Kinases; D019204:GTP-Binding Proteins; C480838:GPA-16 protein, C elegans