A novel CDK-2 homolog identified in lamprey, Lampetra japonica, with roles in apoptosis
CDK-2, a member of the cyclin-dependent kinase family, plays an important role in many cell processes, such as cell cycle regulation, cell growth and differentiation, and cell apoptosis. Lampreys belong to the most primitive vertebrates, and there is no report about the CDK-2 gene in lampreys at present. In this study, a CDK-2-like gene sequence and deduced amino acid sequence were identified in Japanese lamprey (Lampetra japonica, L. japonica). The CDK-2-like gene has about 80% similarity with its homologs in jaw vertebrates. The polyclonal antibody against CDK-2-like was well prepared, and the results showed that CDK-2-like was highly expressed in the gonad tissue of lampreys. Apoptosis could reduce the expression of CDK-2-like in lymphocytes of lamprey, while overexpression of CDK-2-like could inhibit apoptosis. In addition, inhibition of CDK-2-like activity was able to trigger out apoptosis and also helped apoptotic inducer actinomycin D (Act-D) to induce apoptosis. These results suggest that CDK-2-like identified from lamprey may play a crucial role in apoptosis of jawless vertebrates.
KeywordsCDK-2 Lamprey Evolution Apoptosis
Y. X. conceived the study, designed experiments, and wrote the paper. Y. X., Y. T., H. Z., N. Z., and K. R. performed the experiments. Q. L. reviewed the study results and revised the manuscript. All of the authors reviewed the manuscript.
This study was supported by the Project funded by China Postdoctoral Science Foundation (2017M611257), Teachers guide undergraduates scientific research training project of Liaoning Normal University (CX201902062), the National Natural Science Foundation of China (31501911), the General Scientific Research Foundation of Liaoning Educational Committee (L2015293), and the Youth Scientific Research Project of Liaoning Normal University (LS2014L008).
Compliance with ethical standards
The work was confirmed by the animal welfare and Research Ethics Committee of Dalian Medical University (license number SYXK2004-0029), and the methods were carried out according to the approved guidelines.
Conflict of interest
The authors declare that they have no conflict of interest.