• PMID: 25004108
• Gene Name: CCNK
• Condition: Role in spermatogenesis
• Association: Associated
• Sex: Male
• Infertility type: Male infertility
• Other associated phenotypes: Role in spermatogenesis

A distinct expression pattern of cyclin K in mammalian testes suggests a functional role in spermatogenesis

Xiang X, Deng L, Zhang J, Zhang X, Lei T, Luan G, Yang C, Xiao ZX, Li Q, Li Q.

Germ cell and embryonic stem cells are inextricably linked in many aspects. Remarkably both can generate all somatic cell types in organisms. Yet the molecular regulation accounting for these similarities is not fully understood. Cyclin K was previously thought to associate with CDK9 to regulate gene expression. However, we and others have recently shown that its cognate interacting partners are CDK12 and CDK13 in mammalian cells. We further demonstrated that cyclin K is essential for embryonic stem cell maintenance. In this study, we examined the expression of cyclin K in various murine and human tissues. We found that cyclin K is highly expressed in mammalian testes in a developmentally regulated manner. During neonatal spermatogenesis, cyclin K is highly expressed in gonocytes and spermatogonial stem cells. In adult testes, cyclin K can be detected in spermatogonial stem cells but is absent in differentiating spermatogonia, spermatids and spermatozoa. Interestingly, the strongest expression of cyclin K is detected in primary spermatocytes. In addition, we found that cyclin K is highly expressed in human testicular cancers. Knockdown of cyclin K in a testicular cancer cell line markedly reduces cell proliferation. Collectively, we suggest that cyclin K may be a novel molecular link between germ cell development, cancer development and embryonic stem cell maintenance. FAU - Xiang, Xiaocong AU - Xiang X AD - Center of Growth, Metabolism, and Aging, Key Laboratory of Bio-Resources and Eco-Environment, and State Key Laboratory of Biotherapy, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China. FAU - Deng, Li AU - Deng L AD - Center of Growth, Metabolism, and Aging, Key Laboratory of Bio-Resources and Eco-Environment, and State Key Laboratory of Biotherapy, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China. FAU - Zhang, Jingli AU - Zhang J AD - 363 Hospital, Aviation Industry Corporation of China, Chengdu, Sichuan, China. FAU - Zhang, Xudong AU - Zhang X AD - Center of Growth, Metabolism, and Aging, Key Laboratory of Bio-Resources and Eco-Environment, and State Key Laboratory of Biotherapy, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China. FAU - Lei, Tingjun AU - Lei T AD - Center of Growth, Metabolism, and Aging, Key Laboratory of Bio-Resources and Eco-Environment, and State Key Laboratory of Biotherapy, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China. FAU - Luan, Guangxin AU - Luan G AD - Center of Growth, Metabolism, and Aging, Key Laboratory of Bio-Resources and Eco-Environment, and State Key Laboratory of Biotherapy, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China. FAU - Yang, Chunlei AU - Yang C AD - Center of Growth, Metabolism, and Aging, Key Laboratory of Bio-Resources and Eco-Environment, and State Key Laboratory of Biotherapy, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China. FAU - Xiao, Zhi-Xiong AU - Xiao ZX AD - Center of Growth, Metabolism, and Aging, Key Laboratory of Bio-Resources and Eco-Environment, and State Key Laboratory of Biotherapy, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China. FAU - Li, Qian AU - Li Q AD - 363 Hospital, Aviation Industry Corporation of China, Chengdu, Sichuan, China.