Related Experiment Videos
Stability of the prion protein-encoding (PRNP) gene in HeLa cells
Georgios Amexis1, Jeanette Ridge, Larisa Cervenakova
1Center for Biologics Evaluation and Research, United States Food and Drug Administration, 1401 Rockville Pike, HFM-313, Rockville, MD 20852-1448, USA.
Abstract:
To assess the risk of the de novo emergence of the agent of transmissible spongiform encephalopathies in cultured cells, we examined the stability of the prion protein-encoding (PRNP) gene in HeLa cells and in cultures contaminated with HeLa cells that have been passaged extensively for over 50 years. Various sub-lineages of HeLa cells showed that some contained a mixture of a truncated PRNP gene (R3-R4 deletion) and a full-length PRNP gene, while others were homozygous for the R3-R4 deletion. That finding suggests that the progenitor of several popular sub-lineages of HeLa must have lost part or all of chromosome 20 early in the history of HeLa cells. No mutations were found in the PRNP genes. We conclude that the spontaneous appearance of mutations leading to expression of abnormal prion proteins in continuously passaged heteroploid cell lines is unlikely to pose a substantial risk for the safe production of biologicals in such cells.
Insights
The prion protein gene (PRNP) in extensively passaged HeLa cells showed no mutations. This suggests a low risk of abnormal prion protein emergence, ensuring safety in biological production.
Area of Science:
- Cell biology
- Molecular biology
- Neuroscience
Background:
- Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases.
- The prion protein (PrP) is central to TSE pathogenesis.
- Cell culture systems are used in biological production and research.
Purpose of the Study:
- To evaluate the risk of de novo prion protein (PRNP) gene mutations in long-term cultured HeLa cells.
- To assess the stability of the PRNP gene in heteroploid cell lines.
- To determine the safety implications for biological production.
Main Methods:
- Analysis of the PRNP gene in various HeLa cell sub-lineages.
- Examination of cells passaged extensively for over 50 years.
- Genetic sequencing to detect mutations.
Main Results:
- Some HeLa cell sub-lineages exhibited a mixture of full-length and truncated PRNP genes (R3-R4 deletion).
- Other sub-lineages were homozygous for the R3-R4 deletion.
- No spontaneous mutations were detected in the PRNP genes across all tested cell lines.
Conclusions:
- The observed PRNP gene variations likely stem from early chromosomal loss in HeLa cell progenitors.
- The absence of PRNP mutations indicates a low risk for the de novo emergence of abnormal prion proteins.
- Continuously passaged heteroploid cell lines appear safe for biological production regarding prion protein risks.