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Secreted signalling molecules provide cells with positional information that organizes long-range pattern during the development of multicellular animals. Evidence is presented that localized expression of Decapentaplegic instructs cells about their position along the anterior-posterior axis of the Drosophila wing in two distinct ways. One mechanism is(More)
To identify genes involved in the patterning of adult structures, Gal4-UAS (upstream activating site) technology was used to visualize patterns of gene expression directly in living flies. A large number of Gal4 insertion lines were generated and their expression patterns were studied. In addition to identifying several characterized developmental genes,(More)
A genetic and phenotypic analysis of the gene pannier is described. Animals mutant for strong alleles die as embryos in which the cells of the amnioserosa are prematurely lost. This leads to a dorsal cuticular hole. The dorsal-most cells of the imagos are also affected: viable mutants exhibit a cleft along the dorsal midline. pannier mRNA accumulates(More)
The related genes buttonhead (btd) and Drosophila Sp1 (the Drosophila homologue of the human SP1 gene) encode zinc-finger transcription factors known to play a developmental role in the formation of the Drosophila head segments and the mechanosensory larval organs. We report a novel function of btd and Sp1: they induce the formation and are required for the(More)
In the Drosophila wing imaginal disc, the Hedgehog (Hh) signal molecule induces the expression of decapentaplegic (dpp) in a band of cells abutting the anteroposterior (A/P) compartment border. It has been proposed that Dpp organizes the patterning of the entire wing disc. We have tested this proposal by studying the response to distinct levels of ectopic(More)
The notum of Drosophila is a good model system for the study of two-dimensional pattern formation. Attention has mainly focused on the regulation of the spatial expression of the genes of the achaete-scute complex (AS-C) that results in a stereotyped bristle pattern. Expression of AS-C genes has traditionally been viewed as a consequence of the activity of(More)
Mutant larvae for the Drosophila gene lethal giant larva (lgl) develop neoplastic tumors in imaginal discs. However, lgl mutant clones do not form tumors when surrounded by wild-type tissue, suggesting the existence of a tumor-suppressing mechanism. We have investigated the tumorigenic potential of lgl mutant cells by generating wing compartments that are(More)
Pattern formation in developing animals requires that cells exchange signals mediated by secreted proteins. How these signals spread is still unclear. It is generally assumed that they reach their target site either by diffusion or active transport (reviewed in [1] [2]). Here, we report an alternative mode of transport for Wingless (Wg), a member of the Wnt(More)
The pannier (pnr) gene encodes a GATA transcription factor and acts in several developmental processes in Drosophila, including embryonic dorsal closure, specification of cardiac cells and bristle determination. We show that pnr is expressed in the mediodorsal parts of thoracic and abdominal segments of embryos, larvae and adult flies. Its activity confers(More)
In Drosophila, the Ultrabithorax, abdominal-A and Abdominal-B HOX genes of the bithorax complex determine the identity of part of the thorax and the whole abdomen. Either the absence of these genes or their ectopic expression transform segments into the identity of different ones along the antero-posterior axis. Here we show that misexpression of(More)