Conserved sequences at the origin of adenovirus DNA replication

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• Adenovirus DNA replication originates at inverted terminal repeats.
• Replication initiation involves a covalently linked protein-deoxynucleoside primer.
• Virion DNA-protein complexes serve as templates for replication.

Purpose of the Study:

• To investigate the template activity of DNA-protein complexes from different human adenovirus subgroups for DNA replication in vitro.
• To identify conserved sequence features at the origin of replication across various adenovirus serotypes.

Main Methods:

• In vitro DNA replication assays using nuclear extracts from adenovirus type 2-infected HeLa cells.
• Sequencing of inverted terminal repeat DNA from multiple human adenovirus serotypes (Ad4, Ad9, Ad10, Ad31, Ad2, Ad5, Ad7, Ad12, Ad18).
• Comparative sequence analysis of replication origins.

Main Results:

• Virion-derived DNA-protein complexes from five human adenovirus subgroups (A-E) supported in vitro DNA replication.
• Heterologous complexes showed lower activity than homologous Ad2 DNA, suggesting inefficient initiation.
• Sequencing revealed conserved AT-rich and less conserved GC-rich regions at the replication origin, with the latter resembling papovavirus origins.

Conclusions:

• Adenovirus DNA-protein complexes can function as replication templates across different subgroups.
• The origin of replication possesses distinct structural domains potentially mediating a dual initiation mechanism.
• Adenovirus replication may involve a combination of virus-specific protein priming and host replication factor utilization.