DNA cross-linker-induced G2/M arrest in group C Fanconi anemia lymphoblasts reflects normal checkpoint function

Michael Heinrich, Maureen Hoatlin, Amy J. Zigler, Kirsten V. Silvey, Antony C. Bakke, Winifred W. Keeble, Yu Zhi, Carol A. Reifsteck, Markus Grompe, Michael G. Brown, R. Ellen Magenis, Susan Olson, Grover C. Bagby

Research output: Contribution to journalArticle

61 Scopus citations


Cells from individuals with Fanconi anemia (FA) arrest excessively in the G2/M cell cycle compartment after exposure to low doses of DNA cross- linking agents. The relationship of this abnormality to the fundamental genetic defect in such cells is unknown, but many investigators have speculated that the various FA genes directly regulate cell cycle checkpoints. We tested the hypothesis that the protein encoded by the FA group C complementing gene (FAC) functions to control a cell cycle checkpoint and that cells from group C patients (FA[C]) have abnormalities of cell cycle regulation directly related to the genetic mutation. We found that retroviral transduction of FA(C) lymphoblasts with wild-type FAC cDNA resulted in normalization of the cell cycle response to low-dose mitomycin C (MMC). However, when DNA damage was quantified in terms of cytogenetic damage or cellular cytotoxicity, we found similar degrees of G2/M arrest in response to equitoxic amounts of MMC in FA(C) cells as well as in normal lymphoblasts. Similar results were obtained using isogenic pairs of uncorrected, FAC- or mock-corrected (neo only) FA(C) cell lines. To test the function of other checkpoints we examined the effects of hydroxyurea (HU) and ionizing radiation on cell cycle kinetics of FA(C) and normal lymphoblasts as well as with isogenic pairs of uncorrected, FAC-corrected, or mock-corrected FA(C) cell lines. In all cases the cell cycle response of FA(C) and normal lymphoblasts to these two agents were identical. Based on these studies we conclude that the aberrant G2/M arrest that typifies the response of FA(C) cells to low doses of cross-linking agents does not represent an abnormal cell cycle response but instead represents a normal cellular response to the excessive DNA damage that results in FA(C) calls following exposure to low doses of cross-linking agents.

Original languageEnglish (US)
Pages (from-to)275-287
Number of pages13
Issue number1
Publication statusPublished - Jan 1 1998
Externally publishedYes


ASJC Scopus subject areas

  • Hematology

Cite this

Heinrich, M., Hoatlin, M., Zigler, A. J., Silvey, K. V., Bakke, A. C., Keeble, W. W., ... Bagby, G. C. (1998). DNA cross-linker-induced G2/M arrest in group C Fanconi anemia lymphoblasts reflects normal checkpoint function. Blood, 91(1), 275-287.