Ribbon regulates morphogenesis of the Drosophila embryonic salivary gland through transcriptional activation and repression.

Transcription factors affect spatiotemporal patterns of gene expression often regulating multiple aspects of tissue morphogenesis, including cell-type specification, cell proliferation, cell death, cell polarity, cell shape, cell arrangement and cell migration. In this work, we describe a distinct role for Ribbon (Rib) in controlling cell shape/volume increases during elongation of the Drosophila salivary gland (SG). Notably, the morphogenetic changes in rib mutants occurred without effects on general SG cell attributes such as specification, proliferation and apoptosis.

Genome-wide analysis reveals a major role in cell fate maintenance and an unexpected role in endoreduplication for the Drosophila FoxA gene Fork head.

Transcription factors drive organogenesis, from the initiation of cell fate decisions to the maintenance and implementation of these decisions. The Drosophila embryonic salivary gland provides an excellent platform for unraveling the underlying transcriptional networks of organ development because Drosophila is relatively unencumbered by significant genetic redundancy. The highly conserved FoxA family transcription factors are essential for various aspects of organogenesis in all animals that have been studied.

Balancing different types of actin polymerization at distinct sites: roles for Abelson kinase and Enabled.

The proto-oncogenic kinase Abelson (Abl) regulates actin in response to cell signaling. Drosophila Abl is required in the nervous system, and also in epithelial cells, where it regulates adherens junction stability and actin organization. Abl acts at least in part via the actin regulator Enabled (Ena), but the mechanism by which Abl regulates Ena is unknown.

Cytoskeletal connections: building strong cells in new ways.

Cell and tissue integrity requires the coordination of actin and microtubules and the linkage of these cytoskeletal elements to cell junctions. New findings reveal that the cytoskeletal linker protein Short stop works with EB1 and APC1 to help carry out this function.

Drosophila APC2 and APC1 play overlapping roles in wingless signaling in the embryo and imaginal discs.

The regulation of signal transduction plays a key role in cell fate choices, and its disregulation contributes to oncogenesis. This duality is exemplified by the tumor suppressor APC. Originally identified for its role in colon tumors, APC family members were subsequently shown to negatively regulate Wnt signaling in both development and disease.