Reference Report

Reference
Citation	Haralalka, S., Shelton, C., Cartwright, H.N., Katzfey, E., Janzen, E., Abmayr, S.M. (2011). Asymmetric Mbc, active Rac1 and F-actin foci in the fusion-competent myoblasts during myoblast fusion in Drosophila. Development 138(8): 1551--1562. (Export to RIS)
FlyBase ID	FBrf0213340
Publication Type	Research paper
PubMed ID	21389053
PubMed Abstract	Myoblast fusion is an intricate process that is initiated by cell recognition and adhesion, and culminates in cell membrane breakdown and formation of multinucleate syncytia. In the Drosophila embryo, this process occurs asymmetrically between founder cells that pattern the musculature and fusion-competent myoblasts (FCMs) that account for the bulk of the myoblasts. The present studies clarify and amplify current models of myoblast fusion in several important ways. We demonstrate that the non-conventional guanine nucleotide exchange factor (GEF) Mbc plays a fundamental role in the FCMs, where it functions to activate Rac1, but is not required in the founder cells for fusion. Mbc, active Rac1 and F-actin foci are highly enriched in the FCMs, where they localize to the Sns:Kirre junction. Furthermore, Mbc is crucial for the integrity of the F-actin foci and the FCM cytoskeleton, presumably via its activation of Rac1 in these cells. Finally, the local asymmetric distribution of these proteins at adhesion sites is reminiscent of invasive podosomes and, consistent with this model, they are enriched at sites of membrane deformation, where the FCM protrudes into the founder cell/myotube. These data are consistent with models promoting actin polymerization as the driving force for myoblast fusion.
DOI	10.1242/dev.057653
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Language of Publication	English
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Publication Type	Journal
Abbreviation	Development
Title	Development
Publication Year	1987-
ISBN/ISSN	0950-1991
Data from Reference
Aberrations (1)
	Df(1)w67k30
Alleles (17)
	Avic\GFP^{Scer\UAS.T:Hsap\Myr2} Disc\RFP^{mCherry.sns.T:nls-tra} Ecol\lacZ^kirre-rP298 kirre^Scer\UAS.cRa mbc^D11.2 mbc^{NPxxP.Δ1807.Scer\UAS.T:Ivir\HA1} mbc^{Scer\UAS.T:Ivir\HA1} Rac1^J11 Rac1^Scer\UAS.cLa Rac1^V12.Scer\UAS Rac2^Δ rols^7.Scer\UAS rols^1728-20L Scer\GAL4^kirre-rP298 Scer\GAL4^sns.PK Scer\GAL4^twi.PG spg²
Constructs (10)
	P{GAL4-twi.G} P{sns-GAL4.K} P{sns-mCherry.NLS} P{UAS-gapGFP} P{UAS-kirre.R} P{UAS-mbc.HA} P{UAS-mbc.NPxxP.Δ1807.HA} P{UAS-Rac1.L} P{UAS-Rac1.V12} P{UAS-rols.7}
Genes (17)
	Avic\GFP Disc\RFP dlg1 Ecol\lacZ eve kirre Kr mbc Rac1 Rac2 rols rst Scer\GAL4 slou sns spg T:nls-tra
Insertions (2)
	P{GAL4}rP298 P{PZ}rP298