| Autor: |
Li Y; Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States.; Plant Molecular and Cell Biology Program, the Horticultural and Plant Science Department, University of Florida, Gainesville, United States., Liu D; Donald Danforth Plant Science Center, St. Louis, United States., López-Paz C; Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States.; Donald Danforth Plant Science Center, St. Louis, United States., Olson BJ; Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States., Umen JG; Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, United States.; Donald Danforth Plant Science Center, St. Louis, United States. |
| Abstrakt: |
Proliferating cells actively control their size by mechanisms that are poorly understood. The unicellular green alga Chlamydomonas reinhardtii divides by multiple fission, wherein a 'counting' mechanism couples mother cell-size to cell division number allowing production of uniform-sized daughters. We identified a sizer protein, CDKG1, that acts through the retinoblastoma (RB) tumor suppressor pathway as a D-cyclin-dependent RB kinase to regulate mitotic counting. Loss of CDKG1 leads to fewer mitotic divisions and large daughters, while mis-expression of CDKG1 causes supernumerous mitotic divisions and small daughters. The concentration of nuclear-localized CDKG1 in pre-mitotic cells is set by mother cell size, and its progressive dilution and degradation with each round of cell division may provide a link between mother cell-size and mitotic division number. Cell-size-dependent accumulation of limiting cell cycle regulators such as CDKG1 is a potentially general mechanism for size control. |
