[Cloning transforming genes from human papillomavirus type 18]

Area of Science:

• Molecular Biology
• Virology
• Oncology

Context:

• Cervical cancer is frequently associated with persistent infections by high-risk human papillomaviruses (HPVs).
• HPV type 18 is a significant oncogenic strain implicated in a substantial proportion of cervical malignancies.
• Understanding the genetic variations in HPV oncogenes is crucial for comprehending viral oncogenesis and developing targeted therapies.

Purpose:

• To determine the nucleotide sequences of the E6 and E7 genes of human papillomavirus type 18 from cervical tumor DNA.
• To compare these sequences with the prototype variant and identify any mutations.
• To assess the potential impact of identified mutations on the transforming capabilities of the viral genes.

Summary:

• Nucleotide sequences of HPV type 18 E6 and E7 genes from human cervical tumor DNA were determined and compared to a prototype variant.
• Five silent point mutations and one amino acid substitution (lysine to asparagine at codon 129) were found in the E6 gene.
• One significant mutation (codon 92) resulting in an amino acid substitution (lysine to asparagine) was identified in the E7 gene.
• These mutations are located in the 3'-terminal regions and are unlikely to affect the transforming potential of the viral genes.
• E6 and E7 coding regions were amplified by PCR, cloned into a bifunctional expression vector, and verified by sequencing.

Impact:

• Provides detailed genetic information on HPV type 18 variants found in cervical tumors.
• Contributes to the understanding of HPV genetic diversity and its role in cervical carcinogenesis.
• Findings suggest that common mutations in E6 and E7 may not significantly alter their oncogenic activity, potentially influencing therapeutic strategies.