Developmental regulation of oocyte lipid intake through 'patent' follicular epithelium in .

Epithelia form protective permeability barriers that selectively allow the exchange of material while maintaining tissue integrity under extreme mechanical, chemical, and bacterial loads. Here, we report in the follicular epithelium a developmentally regulated and evolutionarily conserved process "patency", wherein a breach is created in the epithelium at tricellular contacts during mid-vitellogenesis. In , patency exhibits a strict temporal range potentially delimited by the transcription factor Tramtrack69 and a spatial pattern influenced by the dorsal-anterior signals of the follicular epithelium.

Endoreplication: The Good, the Bad, and the Ugly.

To battle adverse internal and external conditions and maintain homeostasis, diploid organisms employ various cellular processes, such as proliferation and apoptosis. In some tissues, an alternative mechanism, endoreplication, is employed toward similar goals. Endoreplication is an evolutionarily conserved cell cycle program during which cells replicate their genomes without division, resulting in polyploid cells.