Drosophila myoblast city encodes a conserved protein that is essential for myoblast fusion, dorsal closure, and cytoskeletal organization.
The Drosophila myoblast city (mbc) locus was previously identified on the basis of a defect in myoblast fusion (Rushton et al., 1995. Development [Camb.]. 121:1979-1988). We describe herein the isolation and characterization of the mbc gene. The mbc transcript and its encoded protein are expressed in a broad range of tissues, including somatic myoblasts, cardial cells, and visceral mesoderm. It is also expressed in the pole cells and in ectodermally derived tissues, including the epidermis. Consistent with this latter expression, mbc mutant embryos exhibit defects in dorsal closure and cytoskeletal organization in the migrating epidermis. Both the mesodermal and ectodermal defects are reminiscent of those induced by altered forms of Drac1 and suggest that mbc may function in the same pathway. MBC bears striking homology to human DOCK180, which interacts with the SH2-SH3 adapter protein Crk and may play a role in signal transduction from focal adhesions. Taken together, these results suggest the possibility that MBC is an intermediate in a signal transduction pathway from the rho/rac family of GTPases to events in the cytoskeleton and that this pathway may be used during myoblast fusion and dorsal closure.
Erickson
M R
MR
Department of Biochemistry and Molecular Biology and Center for Gene Regulation, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Galletta
B J
BJ
Abmayr
S M
SM
D000595:Amino Acid Sequence; D000818:Animals; D002459:Cell Fusion; D002465:Cell Movement; D003598:Cytoskeletal Proteins; D003599:Cytoskeleton / Q000648:ultrastructure*; D004330:Drosophila / Q000737:chemistry / Q000196:embryology / Q000235:genetics*; D029721:Drosophila Proteins; D004475:Ectoderm / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D047108:Embryonic Development; D004817:Epidermis / Q000196:embryology / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*; D008297:Male; D008648:Mesoderm / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D018485:Muscle Fibers, Skeletal / Q000166:cytology* / Q000378:metabolism; D011506:Proteins / Q000737:chemistry; D016415:Sequence Alignment; D015398:Signal Transduction; D020744:rac GTP-Binding Proteins
D003598:Cytoskeletal Proteins; C099818:DOCK1 protein, human; D029721:Drosophila Proteins; D019476:Insect Proteins; D011506:Proteins; C107441:mbc protein, Drosophila; D020744:rac GTP-Binding Proteins