Open AccessA Distinct Expression Pattern of Cyclin K in Mammalian Testes Suggests a Functional Role in Spermatogenesis
Author(s) -
Xiaocong Xiang,
Li Deng,
Jingli Zhang,
Xudong Zhang,
Tingjun Lei,
Guangxin Luan,
Cheng Yang,
ZhiXiong Jim Xiao,
Qian Li,
Qintong Li
Publication year - 2014
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0101539
Subject(s) - biology , cyclin , cyclin b1 , microbiology and biotechnology , cyclin a , cyclin a2 , cyclin b , stem cell , cyclin e , cyclin d , spermatogenesis , gonocyte , germ cell , embryonic stem cell , cell cycle , somatic cell , cyclin d1 , gene knockdown , cyclin d2 , cell , cell culture , sertoli cell , genetics , gene , endocrinology , cyclin dependent kinase 1
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.