Mesenchymal Cell Contractility Regulates Villus Morphogenesis and Intestinal Architecture.

The large absorptive surface area of the small intestine is imparted by finger-like projections called villi. Villi formation is instructed by stromal-derived clusters of cells which have been proposed to induce epithelial bending through actomyosin contraction. Their functions in the elongation of villi have not been studied.

β-importin Tnpo-SR promotes germline stem cell maintenance and oocyte differentiation in female Drosophila.

Germ cell development requires interplay between factors that balance cell fate and division. Early in their development, germ cells in many organisms divide mitotically with incomplete cytokinesis. Key regulatory events then lead to the specification of mature gametes, marked by the switch to a meiotic cell cycle program.

Coordinating Proliferation, Polarity, and Cell Fate in the Female Germline.

Gametes are highly specialized cell types produced by a complex differentiation process. Production of viable oocytes requires a series of precise and coordinated molecular events. Early in their development, germ cells are an interconnected group of mitotically dividing cells.

Novel cis-regulatory regions in ecdysone responsive genes are sufficient to promote gene expression in Drosophila ovarian cells.

The insect steroid hormone ecdysone is a key regulator of oogenesis in Drosophila melanogaster and many other species. Despite the diversity of cellular functions of ecdysone in oogenesis, the molecular regulation of most ecdysone-responsive genes in ovarian cells remains largely unexplored. We performed a functional screen using the UAS/Gal4 system to identify non-coding cis-regulatory elements within well-characterized ecdysone-response genes capable of driving transcription of an indelible reporter in ovarian cells.

Temporal remodeling of the cell cycle accompanies differentiation in the Drosophila germline.

Development of multicellular organisms relies upon the coordinated regulation of cellular differentiation and proliferation. Growing evidence suggests that some molecular regulatory pathways associated with the cell cycle machinery also dictate cell fate; however, it remains largely unclear how the cell cycle is remodeled in concert with cell differentiation. During Drosophila oogenesis, mature oocytes are created through a series of precisely controlled division and differentiation steps, originating from a single tissue-specific stem cell.

A Genetic Mosaic Screen Reveals Ecdysone-Responsive Genes Regulating Drosophila Oogenesis.

Multiple aspects of Drosophila oogenesis, including germline stem cell activity, germ cell differentiation, and follicle survival, are regulated by the steroid hormone ecdysone. While the transcriptional targets of ecdysone signaling during development have been studied extensively, targets in the ovary remain largely unknown. Early studies of salivary gland polytene chromosomes led to a model in which ecdysone stimulates a hierarchical transcriptional cascade, wherein a core group of ecdysone-sensitive transcription factors induce tissue-specific responses by activating secondary branches of transcriptional targets.