The early response to DNA damage can lead to activation of alternative splicing activity resulting in CD44 splice...

Area of Science:

• Molecular Biology
• Cell Biology
• Oncology

Background:

• The human papillomavirus 16 E6 oncogene is known to interfere with cellular processes, particularly the p53-dependent response to DNA damage.
• Understanding the early cellular responses to genotoxic stress in the presence of viral oncoproteins is crucial for cancer research.

Purpose of the Study:

• To investigate the influence of the HPV16 E6 oncogene on the early cellular response to DNA damage.
• To identify genes and cellular processes affected by E6 during genotoxic stress, especially in the absence of functional p53.

Main Methods:

• Comparative global gene expression profiling of E6-expressing and control cells after mitomycin C-induced DNA damage.
• Immunoblot analysis to assess protein expression and activation of alternative splicing.
• Small interfering RNA (siRNA) to disrupt splicing factor SRp55 activity.
• Comparison of isogenic cell lines with and without p53 to elucidate the role of p53.

Main Results:

• E6-expressing cells, lacking functional p53, showed activation of a distinct set of genes, including SR splicing factors, unlike p53-expressing cells.
• Increased expression of SR proteins and activation of alternative splicing were observed in E6-expressing cells during early DNA damage response.
• Disrupting splicing factor SRp55 increased the viability of p53-deficient cells post-DNA damage.
• The observed increase in splicing activity was dependent on the absence of p53.
• Both E6-expressing and p53-deficient cells exhibited altered splicing patterns for the CD44 receptor.

Conclusions:

• Cells lacking p53 can activate alternative splicing pathways in response to DNA damage.
• The HPV16 E6 oncogene promotes alternative splicing in a p53-independent manner, potentially contributing to cellular adaptation and survival under genotoxic stress.
• Alternative splicing represents a significant cellular response in p53-deficient cells facing DNA damage.