Dynamic expression of d-CdGAPr, a novel Drosophila melanogaster gene encoding a GTPase activating protein

Small GTPases of the rho family function as signal transducer for extra-cel lular stimuli to control cytoskeletal re-organization and a variety of othe r cellular processes including adhesion, proliferation and transcriptional regulation (Hall, A., 1998. RhoGTPases and the actin cytoskeleton. Science 279, 509-514). Usually widely expressed, their activities are tightly contr olled by conformational changes induced by hydrolysis of the GTP bound mole cule (Bourne H.R., Sanders D.A., 1990. The GTPase superfamily: a conserved switch for diverse cell functions. Nature 348, 125-132). Conversion of GTP to GDP relies on a rho intrinsic GTPase domain that requires GTPase activat ing proteins (GAPs) for potent activity (Lamarche, N., Hall. A., 1994. GAPs for rho-related GTPases. Trends Genet. 10, 436-440). Here we report on the identification of a novel Drosophila GAP gene, d-CdGAPr, encoding a protei n related to mammalian CdGAPs. The gene is expressed throughout development as well as in adults. Spatio-temporal transcription pattern of d-CdGAPr du ring embryogenesis is highly dynamic. Abundant in the pre-blastoderm embryo prior to the onset of zygotic transcription, messengers accumulate at the blastoderm posterior pole after cellularisation. During gastrulation and su bsequent development, all cells accumulate low levels of d-CdGAPr RNA, whil e a few territories transiently display stronger expression. Sites of prefe rential expression include the posterior pole of the early cellular blastod erm, the neuro-ectoderm prior to neuroblast delamination, rows of epidermal cells in the most posterior part of thoracic and first abdominal segments and a ring of epidermal cells at the posterior end of the embryo. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.