Chromosoma

, Volume 113, Issue 2, pp 62–68

Genomic instability in both wild-type and telomerase null MEFs

Authors

  • Ling-Yang Hao
    • Graduate Program in Human Genetics, Department of Molecular Biology and GeneticsJohns Hopkins University School of Medicine
    • Graduate Program in Human Genetics, Department of Molecular Biology and GeneticsJohns Hopkins University School of Medicine
Research Article

DOI: 10.1007/s00412-004-0291-7

Cite this article as:
Hao, L. & Greider, C.W. Chromosoma (2004) 113: 62. doi:10.1007/s00412-004-0291-7

Abstract

To examine chromosome instability in the absence of telomerase, we established mouse embryonic fibroblast (MEF) lines from late generation mTR−/− and wild-type animals and examined metaphases using telomere fluorescence in situ hybridization (FISH) and spectral karyotyping (SKY). In early passages, mTR−/− G6 cell lines showed more chromosome ends with no telomere signal, more chromosome end-to-end fusions and greater radiosensitivity than wild-type lines. At later passages, however, the rate of genomic instability in the wild-type MEFs increased to a level similar or higher than seen in the mTR−/− G6 cell lines. This high degree of instability in wild-type MEF lines suggests that post-crisis MEFs should not be considered genetically defined cell lines. Surprisingly, the increased radiosensitivity seen in early passage mTR−/− G6 cultures was lost after crisis. Both post-crisis mTR−/− G6 MEFs and wild-type MEFs showed loss of p53 and γ-H2AX phosphorylation in response to irradiation, indicating a loss of DNA damage checkpoints.

Supplementary material

412_2004_0291.pdf (529 kb)
(PDF 397 KB)

Copyright information

© Springer-Verlag 2004