β3 tubulin expression characterizes the differentiating mesodermal germ layer during Drosophila embryogenesis

Abstract

During embryogenesis, the β3 tubulin gene of Drosophila is transcribed predominantly in the mesoderm. We have raised antibodies specific to the C-terminal domain of the β3 tubulin and analysed by immunostaining the distribution of this tubulin isotype during Drosophila embryogenesis. The protein is first detectable in the cephalic mesoderm at maximal germband extension. Shortly afterwards, β3 tubulin is expressed in single cells at identical positions of the thoracic and abdominal segments. We suggest that these cells represent muscle pioneer cells of Drosophila. During later embryonic development the somatic musculature, musculature, visceral musculature, dorsal vessel and macrophages contain β3 tubulin. In dorsalizing mutants dorsal, snail and twist, which do not form a ventral furrow during gastrulation, β3 expression is greatly reduced but not completely abolished. Our analysis shows that β3 tubulin immunostaining characterizes the differentiation of mesodermal derivatives during embryogenesis