Serrano (Sano) Functions with the Planar Cell Polarity Genes to Control Tracheal Tube Length

Epithelial tubes are the functional units of many organs, and proper tube geometry is crucial for organ function. Here, we characterize serrano (sano), a novel cytoplasmic protein that is apically enriched in several tube-forming epithelia in Drosophila, including the tracheal system. Loss of sano results in elongated tracheae, whereas Sano overexpression causes shortened tracheae with reduced apical boundaries. Sano overexpression during larval and pupal stages causes planar cell polarity (PCP) defects in several adult tissues. In Sano-overexpressing pupal wing cells, core PCP proteins are mislocalized and prehairs are misoriented; sano loss or overexpression in the eye disrupts ommatidial polarity and rotation. Importantly, Sano binds the PCP regulator Dishevelled (Dsh), and loss or ectopic expression of many known PCP proteins in the trachea gives rise to similar defects observed with loss or gain of sano, revealing a previously unrecognized role for PCP pathway components in tube size control

Independence of the numbers of legs and leg ganglia in Drosophila bithorax mutants

A prominent feature of most central nervous systems is the presence of highly organized association centres, often called 'nuclei' in vertebrate brains and 'glomeruli' or 'neuromeres' in invertebrate brains and ventral ganglia. As little is known of the processes leading to the formation of these centres, we have investigated this question in the case of the leg neuromeres of Drosophila. The thoracico-abdominal ganglion of wild-type flies contains six conspicuous neuromeres, each associated with a leg. In bithoraxoid (bxd) mutants, the first abdominal segment is transformed to thoracic, and one or two additional legs may develop. We show here that supernumerary neuromeres may also be observed in this mutant. However, in a given individual the number of neuromeres is independent of the number of legs. In Hyperabdominal (Hab) mutants, the metathoracic segment is transformed to abdominal, and the metathoracic legs may be missing. The ganglia of four-legged mutants show a variable reduction of the metathoracic leg neuromeres. We conclude that the formation of a leg neuromere is genetically controlled and does not depend on the presence of a corresponding leg.SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe