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Border Cells (Drosophila)
The border cells are a cluster of 6-8 cells that migrate in the ovariole of the fruit-fly ''Drosophila melanogaster,'' during the process of oogenesis. A fly ovary consists of a string of ovarioles or egg chambers arranged in an increasing order of maturity. Each egg chamber contains 16 central germline, nurse cells surrounded by a monolayer epithelium of nearly 1000 Ovarian follicle, follicle cells. At stage 8 of oogenesis, these cells initiate invading the neighbouring nurse cells, and reach the oocyte boundary by Stage 10. Mechanism of Action The border cells are specified by the activation of the JAK-STAT signaling pathway, JAK-STAT pathway in response to the cytokine, Unpaired. The signaling initiates by binding of Unpaired ligand to the Domeless receptor. The migratory fate is acquired by the activation of ''slbo','' a transcription factor that leads to the transformation of stationary follicle cells into the migratory border cell fate by regulating the expression of vario ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovariole
An ovariole is a tubular component of the insect ovary, and the basic unit of egg production. Each ovariole is composed of a germarium (the germline stem cell niche) at the anterior tip, a set of developing oocytes contained within follicles, and a posterior connection to a common oviduct. While most insects have two ovaries, the number of ovarioles within each ovary varies across insect species. This number may also be variable across individuals within a species, or between the left and right ovaries within an individual. Types Ovarioles are often classified into one of several types by the presence and position of nurse cells. These specialized cells provide nutrition and molecules important for embryonic patterning to the developing oocyte. Ovarioles that lack nurse cells are referred to as ''panoistic'' and ovarioles with nurse cells are referred to as ''meroistic''. Meroistic ovarioles are further classified according to where nurse cells are located. In ''polytrophic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
