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[摘要]：Microtubules are necessary for fusion and elongation of vertebrate muscle cells. In Drosophila, several isoforms of beta-Tubulin, the functional subunit of microtubules, are expressed in different tissues of the developing embryo, while solely the beta 3-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 beta 3-Tubulin loss of function mutants. Furthermore, we show that beta 2-Tubulin transcripts are not detectable in embryos and an exceptional zygotic beta 1-Tubulin expression in beta 3-Tubulin mutants cannot be observed. Nevertheless, a maternally contributed beta 1-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 beta 3-Tubulin mutant situation. Our results indicate that the maternally supplied beta 1-Tubulin based microtubule network is sufficient for myoblast fusion, myotube elongation and sarcomere formation both during visceral and somatic muscle development in Drosophila embryogenesis. (C) 2011 Elsevier GmbH. All rights reserved. |
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