Regulating mitosis and meiosis in the male germ line: critical functions for cyclins

Abstract

Key components of the cell cycle machinery are the regulatory subunits, the cyclins, and their catalytic partners the cyclin-dependent kinases. Regulating the cell cycle in the male germ line cells represents unique challenges for this machinery given the constant renewal of gametes throughout the reproductive lifespan and the induction of the unique process of meiosis, a highly specialized kind of cell division. With challenges come opportunities to the critical eye, recognizing that understanding these specialized modes of regulation will provide considerable insight into both normal differentiation as well as disease conditions, including infertility and oncogenesis.

Figure 1.

Cartoon summarizing the meiotic stages of spermatogenesis in which cyclin expression has been documented. The arrows represent cellular progression through spermatogenesis. Cyclins listed are expressed as protein in that specific stage. The coloured bars at the bottom denote the cell type shown directly above.