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Electrophoretic Analysis of Replication Through Structure-Prone DNA Repeats Within the SV40-Based Human Episome
Published on: September 13, 2024
Replication stress and mitotic dysfunction in cells expressing simian virus 40 large T antigen
Liang Hu1, Harilaos Filippakis, Haomin Huang
1Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA.
Journal of Virology
|September 27, 2013
Summary
Simian virus 40 (SV40) large T antigen (LT) binding to Bub1 kinase causes chromosomal instability. This interaction triggers DNA damage response and segregation defects, leading to cancer progression.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Simian virus 40 (SV40) large T antigen (LT) interacts with Bub1 kinase, a critical regulator of spindle checkpoint and chromosome segregation.
- Bub1 mutations are implicated in chromosome missegregation and human cancers.
Purpose of the Study:
- To investigate the role of SV40 LT binding to Bub1 in inducing chromosomal instability.
- To elucidate the mechanisms by which LT binding to Bub1 leads to genomic instability.
Main Methods:
- Time-lapse microscopy to observe metaphase-to-anaphase transition.
- Kinetochore fiber analysis to assess kinetochore-microtubule attachments.
- Inducible LT cell lines to study DNA damage response (DDR) activation.
- Analysis of replication stress markers.
Main Results:
- LT binding to Bub1 induces micronuclei, lagging chromatin, and anaphase bridges, hallmarks of chromosomal instability (CIN).
- LT binding causes a delay in metaphase-to-anaphase transition and aberrant kinetochore-microtubule attachments.
- DNA damage response (DDR) activation precedes chromosome segregation defects and can occur independently.
- Replication stress signatures were observed and could be attenuated by nucleoside supplementation.
Conclusions:
- SV40 LT binding to Bub1 is a key driver of chromosomal instability and genomic instability.
- DDR activation by LT occurs early and can be independent of segregation defects, potentially linked to replication stress.
- A model is proposed integrating LT-induced genomic instability manifestations.
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