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Comparative analysis of pre-replication complex proteins in transformed and normal cells
Domenic Di Paola1, Maria Zannis-Hadjopoulos
1Goodman Cancer Research Center, McGill University, Montreal, Quebec, Canada H3G 1Y6.
Journal of Cellular Biochemistry
|December 3, 2011
Summary
Cellular transformation increases pre-replication complex (pre-RC) proteins, enhancing chromatin binding and origin activity at specific sites like c-myc. Housekeeping origins, such as lamin B2, remain unaffected, indicating transformation-specific alterations in DNA replication initiation.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- The pre-replication complex (pre-RC) is crucial for initiating DNA replication.
- Understanding alterations in pre-RC components during cellular transformation is key to comprehending cancer development.
Purpose of the Study:
- To quantitatively analyze the abundance and chromatin association of major pre-RC proteins in normal versus transformed cells.
- To investigate the impact of cellular transformation on the activity of specific replication origins.
Main Methods:
- Comparative and quantitative analysis of pre-RC proteins (ORC1-6, Cdc6, Cdt1, MCM4/7) and other replication factors (Ku70/86, 14-3-3, Cdc45, PCNA).
- Assessment of protein association with chromatin and activity at specific replication origins (lamin B2, c-myc, 20mer1, 20mer2) in normal and transformed cell lines.
Main Results:
- Transformed cells exhibit overexpression and increased chromatin binding of pre-RC proteins compared to normal cells.
- Specific origins (20mer1, 20mer2, c-myc) show 2-3 fold higher activity and pre-RC association in transformed cells.
- The lamin B2 origin, associated with a housekeeping gene, shows similar activity and pre-RC association in both cell types.
Conclusions:
- Cellular transformation leads to overexpression and enhanced chromatin association of pre-RC proteins.
- Transformation selectively increases the activity of certain replication origins, suggesting dysregulation of DNA replication initiation.
- This comprehensive analysis provides insights into the molecular mechanisms underlying altered replication in transformed cells.
