Virology Unit 5

• papoviruses
• adenoviruses
• herpesviruses
• poxviruses (reproduce in cytoplasm/ use own enzymes)

Early genes expressed immediately upon infection produce nonstructural regulatory proteins that promote transcription and replication.

Late genes transcribed after DNA replication has begun and code structural components.

• polyomavirinae and papillomavirinae: subfamilies
• Smallest dsDNA viruses
• Icosahedral/ No envelope/ Circular dsDNA
• Enter by endocytic vesicle to nucleus to uncoat
• Differential splicing prod diff mRNA from one transcript

The start of a protein or polypeptide terminated by an amino acid with a free amine group (-NH2)

The end of an amino acid chain (protein orpolypeptide), terminated by a free carboxyl group (-COOH).

• Large T antigen mediates shift from early to late transcription.
• Feedback regultion: binds to promotor of its own gene supressing transcription.
• Has ATPase, adenylate & helicase activity in replication.
• Interacts with cell proteins to control DNA replication