The syncytial visceral and somatic musculature develops independently of β3-Tubulin during Drosophila embryogenesis, while maternally supplied β1-Tubulin is stable until the early steps of myoblast fusion.
Microtubules are necessary for fusion and elongation of vertebrate muscle cells. In Drosophila, several isoforms of β-Tubulin, the functional subunit of microtubules, are expressed in different tissues of the developing embryo, while solely the β3-Tubulin isoform is detected in large amounts during differentiation of the somatic and visceral musculature. Here we show the unexpected result that all mesodermal tissues develop correctly in β3-Tubulin loss of function mutants. Furthermore, we show that β2-Tubulin transcripts are not detectable in embryos and an exceptional zygotic β1-Tubulin expression in β3-Tubulin mutants cannot be observed. Nevertheless, a maternally contributed β1-Tubulin-GFP fusion protein (from protein trap collection, Buszczak et al., 2007, Genetics 175, 1505-1531) acts in a dominant negative way, disturbing embryonic development from early stages on. This effect can be observed to the same extent in a zygotic β3-Tubulin mutant situation. Our results indicate that the maternally supplied β1-Tubulin based microtubule network is sufficient for myoblast fusion, myotube elongation and sarcomere formation both during visceral and somatic muscle development in Drosophila embryogenesis.
Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch-Str. 8, 35043 Marburg, Germany.
Anja
A
Rudolf
Detlev
D
Buttgereit
Karl-Heinz
KH
Rexer
Renate
R
Renkawitz-Pohl
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000196:embryology* / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D009024:Morphogenesis / Q000235:genetics; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism*; D032446:Myoblasts / Q000378:metabolism* / Q000648:ultrastructure; D012518:Sarcomeres / Q000378:metabolism* / Q000648:ultrastructure; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D029721:Drosophila Proteins; D050505:Mutant Proteins; C569263:Swip-1 protein, Drosophila; D014404:Tubulin