Rac function and regulation during Drosophila development.
Rac GTPases regulate the actin cytoskeleton to control changes in cell shape. To date, the analysis of Rac function during development has relied heavily on the use of dominant mutant isoforms. Here, we use loss-of-function mutations to show that the three Drosophila Rac genes, Rac1, Rac2 and Mtl, have overlapping functions in the control of epithelial morphogenesis, myoblast fusion, and axon growth and guidance. They are not required for the establishment of planar cell polarity, as had been suggested on the basis of studies using dominant mutant isoforms. The guanine nucleotide exchange factor, Trio, is essential for Rac function in axon growth and guidance, but not for epithelial morphogenesis or myoblast fusion. Different Rac activators thus act in different developmental processes. The specific cellular response to Rac activation may be determined more by the upstream activator than the specific Rac protein involved.
Hakeda-Suzuki
Satoko
S
Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria.
Ng
Julian
J
Tzu
Julia
J
Dietzl
Georg
G
Sun
Yan
Y
Harms
Matthew
M
Nardine
Tim
T
Luo
Liqun
L
Dickson
Barry J
BJ
D000818:Animals; D001369:Axons / Q000502:physiology; D002465:Cell Movement; D016764:Cell Polarity; D004330:Drosophila / Q000196:embryology / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D005260:Female; D017344:Genes, Insect; D008297:Male; D009154:Mutation; D009420:Nervous System / Q000196:embryology; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000502:physiology*; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000502:physiology*; D000097766:RAC2 GTP-Binding Protein
D029721:Drosophila Proteins; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein; D000097766:RAC2 GTP-Binding Protein