Loss of CABLES1, a Cyclin-dependent Kinase-interacting Protein that Inhibits Cell Cycle Progression, Results in Germline Expansion at the Expense of Oocyte Quality in Adult Female Mice

Ho-Joon Lee, Hideo Sakamoto, Hongwei Luo, Malgorzata E. Skaznik-Wikiel, Anne M. Friel, Teruko Niikura, Jacqueline C. Tilly, Yuichi Niikura, Rachael Klein, Aaron K. Styer, Lawrence R. Zukerberg, Jonathan L. Tilly and Bo. R. Rueda

volume 6 | issue 21

1 November 2007
Pages: 2678 - 2684

This is an open-access article

Download PDF

If the document does not open, please right-click on the link (control-click on a Macintosh) and select the option to save the file to disk.

Recent studies have shown that cell cycle inhibitors encoded by the Ink4a gene locus constrain the self-renewing activity of adult stem cells of the hematopoietic and nervous systems. Here we report that knockout (KO) of the Cables1 [cyclin-dependent kinase (CDK)-5 and ABL enzyme substrate 1] cell cycle-regulatory gene in mice has minimal to no effect on hematopoietic stem cell (HSC) dynamics. However, female Cables1-null mice exhibit a significant expansion of germ cell (oocyte) numbers throughout adulthood. This is accompanied by a dramatic elevation in the number of atretic immature oocytes within the ovaries and an increase in the incidence of degenerating oocytes retrieved following superovulation of CABLES1-deficient females. These outcomes are not observed in mice lacking p16^INK4a alone or both p16^INK4a and p19^ARF. These data support recent reports that adult female mice can generate new oocytes and follicles but the enhancement of postnatal oogenesis by Cables1 KO appears offset by a reduction in oocyte quality, as reflected by increased elimination of these additional germ cells via apoptosis. This work also reveals cell lineage specificity with respect to the role that specific CDK-interacting proteins play in restraining the activity of adult germline versus somatic stem cells.