The D-type cyclins (D1, D2 and D3) are critical governors of the cell-cycle clock apparatus during the G1 phase of the mammalian cell cycle. These three D-type cyclins are expressed in overlapping, apparently redundant fashion in the proliferating tissues. A human D-type cyclin gene (CCND1/cyclin D1/PRAD1) was isolated and identified as a candidate Bcl1 oncogene. Xiong et al. (1992) reported the molecular cloning of two additional human D-type cyclin genes, CCND2 (cyclin D2) and CCND3 (cyclin D3). All three human D-type cyclin genes encode small (33-34 kDa) proteins that share an average of 57% identity over the entire coding region and 78% in the cyclin box.
NCBI Summary:
The protein encoded by this gene belongs to the highly conserved cyclin family, whose members are characterized by a dramatic periodicity in protein abundance through the cell cycle. Cyclins function as regulators of CDK kinases. Different cyclins exhibit distinct expression and degradation patterns which contribute to the temporal coordination of each mitotic event. This cyclin forms a complex with and functions as a regulatory subunit of CDK4 or CDK6, whose activtiy is required for cell cycle G1/S transition. This protein has been shown to interact with and be involved in the phosphorylation of tumor suppressor protein Rb. The CDK4 activity associated with this cyclin was reported to be necessary for cell cycle progression through G2 phase into mitosis after UV radiation.
General function
Cell death/survival, Cell cycle regulation
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Cellular localization
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Ovarian function
Oogenesis
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Expression regulated by
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Ovarian localization
Oocyte, Theca, Luteal cells
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Robker et al. (1998) showed that cyclin D2 mRNA was specifically localized to granulosa cells of growing follicles, while cyclin D1 and cyclin D3 were restricted to theca cells.
Zhang et al. (1999) showed that cyclin D3 localization was predominantly in the nuclei of oocytes in primordial and small follicles, a localization that diminished with oocyte growth.
Follicle stages
Primordial, Primary, Secondary, Antral, Preovulatory, Corpus luteum
Comment
Hampl A, et al reported levels and interactions of p27, cyclin D3, and CDK4 during the formation and maintenance of the corpus luteum in mice.