title: Effects of p21 Gene Down-Regulation through RNAi on Antler Stem Cells In Vitro.
abstract: Cell cycle is an integral part of cell proliferation, and consists mainly of four phases, G1, S, G2 and M. The p21 protein, a cyclin dependent kinase inhibitor, plays a key role in regulating cell cyclevia G1 phase control. Cells capable of epimorphic regeneration have G2/M accumulation as their distinctive feature, whilst the majority of somatic cells rest at G1 phase. To investigate the role played byp21 in antler regeneration, we studied the cell cycle distribution of antler stem cells (ASCs), via down-regulation of p21 in vitro using RNAi. The results showed that ASCs had high levels of p21 mRNA expression and rested at G1 phase, which was comparable to the control somatic cells. Down-regulation of p21 did not result in ASC cell cycle re-distribution toward G2/M accumulation, but DNA damage and apoptosis of the ASCs significantly increased and the process of cell aging was slowed. These findings suggest that the ASCs may have evolved to use an alternative, p21-independent cell cycle regulation mechanism. Also a unique p21-dependent inhibitory effect may control DNA damage as a protective mechanism to ensure the fast proliferating ASCs do not become dysplastic/cancerous. Understanding of the mechanism underlying the role played by p21 in the ASCs could give insight into a mammalian system where epimorphic regeneration is initiated whilst the genome stability is effectively maintained.
authors: Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun, Jilin, P. R. China; State Key Laboratory for Molecular Biology of Special Economic Animals, Jilin, P. R. China.
authors: Qianqian
authors: Q
authors: Guo
authors: Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun, Jilin, P. R. China; State Key Laboratory for Molecular Biology of Special Economic Animals, Jilin, P. R. China.
authors: Datao
authors: D
authors: Wang
authors: Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun, Jilin, P. R. China; State Key Laboratory for Molecular Biology of Special Economic Animals, Jilin, P. R. China.
authors: Zhen
authors: Z
authors: Liu
authors: Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun, Jilin, P. R. China; State Key Laboratory for Molecular Biology of Special Economic Animals, Jilin, P. R. China.
authors: Chunyi
authors: C
authors: Li
mesh_terms: D000818:Animals; D000999:Antlers / Q000166:cytology*; D017209:Apoptosis / Q000235:genetics; D049109:Cell Proliferation; D016922:Cellular Senescence / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000172:deficiency* / Q000235:genetics*; D004249:DNA Damage / Q000235:genetics; D003670:Deer; D015536:Down-Regulation / Q000235:genetics*; D059585:G1 Phase Cell Cycle Checkpoints / Q000235:genetics; D055785:Gene Knockdown Techniques; D008297:Male; D034622:RNA Interference; D013234:Stem Cells / Q000166:cytology*
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21