The Oikopleura coenocyst, a unique chordate germ cell permitting rapid, extensive modulation of oocyte production |
| |
Authors: | Ganot Philippe Bouquet Jean-Marie Kallesøe Torben Thompson Eric M |
| |
Institution: | Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. |
| |
Abstract: | The ability to adjust reproductive output to environmental conditions is important to the fitness of a species. The semelparous, chordate, Oikopleura dioica, is particularly adept in producing a highly variable number of oocytes in its short life cycle. Here we show that this entails an original reproductive strategy in which the entire female germline is contained in a single multinucleate cell, the "coenocyst". After an initial phase of syncytial nuclear proliferation half of the nuclei entered meiosis whereas the other half became highly polyploid. The inner F-actin network, with associated plasma membranes, formed a highly ramified infrastructure in which each meiotic nucleus was contained in a pseudo-compartmentalized pro-oocyte linked to the common cytoplasm via ring canals. At a set developmental time, a subset of the pro-oocytes was selected for synchronous growth and the common coenocyst cytoplasm was equally partitioned by transfer through the ring canals. Examination of related species indicated that the coenocyst arrangement is a conserved feature of Appendicularian oogenesis allowing efficient numerical adjustment of oocyte production. As Appendicularia are the second most abundant class of zooplankton, with a world-wide distribution, the coenocyst is clearly a common and successful reproductive strategy on a global scale. |
| |
Keywords: | Vasa Nuage Gamete Larvacean Germline cyst Intercellular bridge Clutch manipulator Ascidian Prophase I Endoreplication |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|