Expression data from early Drosophila embryo

Morphogenesis of epithelial tissues relies on the precise developmental control of cell polarity and architecture. In the early Drosophila embryo, the primary epithelium forms during cellularisation, following a tightly controlled genetic programme where specific sets of genes are up-regulated. Some of them, for instance, control membrane invagination between the nuclei anchored at the apical surface of the syncytium. We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. Keywords: time course Drosophila embryos were selected at successive stages of early development for RNA extraction and hybridization on Affymetrix microarrays. We sought to obtain homogeneous populations of embryos at each developmental stage in order to increase the temporal resolution of expression profiles. To that end, we hand-selected embryos according to morphological criteria at five time-points: before pole cell formation, i.e. before zygotic transcription (T0), during the slow phase (T1) and the fast phase (T2) of cellularisation and at the beginning (T3) and the end (T4) of gastrulation.