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Female mouse germ cells form synchronously dividing cysts
1Howard Hughes Medical Institute Research Laboratories, Department of Embryology, Carnegie Institution of Washington, Baltimore, MD 21210, USA.
Abstract:
Oocytes from many invertebrates initiate development within distinctive cysts of interconnected cells, which are formed through synchronous divisions of a progenitor cell. Recently, processes underlying cyst formation have been extensively characterized at the molecular level in Drosophila. Defects in this process cause sterility in female flies. Early female mouse germ cells are organized as cell clusters as well, but it is uncertain whether these groups are similar to the cysts of invertebrates. We find that mouse germ cells are connected by intercellular bridges in the ovaries of 11.5 to 17.5 days postcoitum embryos; microtubules and organelles have been observed within these bridges. Confocal microscopy shows that cells within mouse clusters divide synchronously and frequently correspond in number to powers of two. Thus, female mouse germ cell clusters exhibit key characteristics of invertebrate germline cysts indicating that the process of germline cyst formation is conserved in the mouse.
Insights
Female mouse germ cells form interconnected clusters, similar to invertebrate germline cysts. These clusters exhibit synchronous cell division, suggesting a conserved mechanism for oocyte development in mammals.
Area of Science:
- Developmental biology
- Cell biology
- Reproductive biology
Background:
- Oocyte development in invertebrates often involves interconnected cell cysts formed by synchronous cell divisions.
- The organization of early female mouse germ cells into clusters suggests potential similarities to invertebrate germline cysts.
- Understanding germ cell organization is crucial for reproductive health and fertility studies.
Purpose of the Study:
- To investigate whether early female mouse germ cell clusters share characteristics with invertebrate germline cysts.
- To determine if germ cell clusters in mouse embryos are formed through conserved developmental processes.
Main Methods:
- Ovaries from mouse embryos (11.5-17.5 days postcoitum) were examined.
- Confocal microscopy was used to visualize germ cell clusters and intercellular bridges.
- Microtubules and organelles within intercellular bridges were analyzed.
Main Results:
- Mouse germ cells in embryonic ovaries are connected by intercellular bridges containing microtubules and organelles.
- Cells within these mouse germ cell clusters divide synchronously.
- The number of cells in mouse clusters often corresponds to powers of two, mirroring invertebrate cyst formation.
Conclusions:
- Female mouse germ cell clusters display key features of invertebrate germline cysts.
- Germline cyst formation appears to be a conserved process between invertebrates and mammals.
- This conserved mechanism highlights fundamental aspects of oocyte development across species.