Adenovirus

     Adenoviridae

Characteristics of Adenoviruses

• Naked icosahedral virus (25 icosahedral capsid)
• Linear ds DNA genome
• Transcription and genome replication are nuclear
• First isolated in the adenoids (or tonsils) 

Virion Structure

• naked icosahedral viruses
• T=25
• Long and distinct fiber projections

Genome Organization

• 5ʼ ends of the genome are covalently linked to terminal protein (TP; primer for DNA replication,E2) 
• Encode a viral DNA polymerase (E2B)
• Encode for genes that move cells into S phase (E1A,E1B)
• In Transcription: Transcripts are capped and polyadenylated and mRNAs are extensively spliced

Adenovirus Replication Cycle

• Attachment –spike protein
• Endocytosis
• Delivery of DNA to nucleus
• Early gene transcription
• DNA replication –viral DNA pol
• Late gene transcription
• Assembly (nuclear)
• Release with cell death

Proteins

• E1A: induces S phase; inhibits transcription of interferon response genes; blocks transcription of MHC class 1 genes
• E1B: induces s phase; inhibits apotosis
• E2: directly involved in viral DNA replication
• E3 genes inhibit apoptosis and down-regulate MHC Class I expression
• E4 encodes proteins needed for viral mRNA transcription; mRNA transport; viral DNA replication

Diseases

• Common Cold
• Pharyngitis
• Gasteroenteritis
• Pneumonia
• Oncolytic Adenoviruses