An important role for CDK2 in G1 to S checkpoint activation and DNA damage response in human embryonic stem cells

Irina Neganova, Felipe Vilella, Stuart P. Atkinson, Maria Lloret, João F. Passos, Thomas Von Zglinicki, José Enrique O'Connor, Deborah Burks, Richard Jones, Lyle Armstrong, Majlinda Lako

Research output: Contribution to journalArticle

80 Scopus citations

Abstract

A precise understanding of mechanisms used by human embryonic stem cells (hESCs) to maintain genomic integrity is very important for their potential clinical applications. The G1 checkpoint serves to protect genomic integrity and prevents cells with damaged DNA from entering S-phase. Previously, we have shown that downregulation of cyclindependent kinase 2 (CDK2) in hESC causes G1 arrest, loss of pluripotency, upregulation of cell cycle inhibitors p21 and p27 and differentiation toward extraembryonic lineages. In this study, we investigate in detail the role of CDK2 in cellular processes, which are crucial to the maintenance of genomic stability in hESC such as G1 checkpoint activation, DNA repair, and apoptosis. Our results suggest that downregulation of CDK2 triggers the G1 checkpoint through the activation of the ATM-CHK2-p53-p21 pathway. Downregulation of CDK2 is able to induce sustained DNA damage and to elicit the DNA damage response (DDR) as evidenced by the formation of distinct c-H2.AX and RAD52-BRCA1 foci in hESC nuclei. CDK2 downregulation causes high apoptosis at the early time points; however, this is gradually decreased overtime as the DDR is initiated. Our mass spectrometry analysis suggest that CDK2 does interact with a large number of proteins that are involved in key cellular processes such as DNA replication, cell cycle progression, DNA repair, chromatin modeling, thus, suggesting a crucial role for CDK2 in orchestrating a fine balance between cellular proliferation, cell death, and DNA repair in hESC.

Original languageEnglish (US)
Pages (from-to)651-659
Number of pages9
JournalStem Cells
Volume29
Issue number4
DOIs
StatePublished - Apr 1 2011

Keywords

  • Apoptosis
  • Ataxia telangiectasia mutated
  • CHK2
  • Cyclin-dependent kinase 2
  • DNA damage
  • G1 checkpoint
  • Human embryonic stem cells

ASJC Scopus subject areas

  • Molecular Medicine
  • Developmental Biology
  • Cell Biology

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    Neganova, I., Vilella, F., Atkinson, S. P., Lloret, M., Passos, J. F., Von Zglinicki, T., O'Connor, J. E., Burks, D., Jones, R., Armstrong, L., & Lako, M. (2011). An important role for CDK2 in G1 to S checkpoint activation and DNA damage response in human embryonic stem cells. Stem Cells, 29(4), 651-659. https://doi.org/10.1002/stem.620