Poxvirus III Polyomavirus Lecture 13

Knipe dm howley pm polyomaviruses unifying properties

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Budgerigar fledgling disease virus Host Mouse Rhesus Monkey Human Human Mouse Hamster African Green Monkey Baboon Rabbit Stump-Tailed Macaque Bird Source: Fields Virology, 4th Ed. Knipe, DM & Howley PM. Polyomaviruses Unifying Properties • Similar sized capsid structure made from three viral proteins • No envelope • Circular, dsDNA genome ~ 5,000 base pairs • All encode a similar set of proteins Polyomavirus Virion Cellular Histones: H2A H2B H3 H4 Source: http://education.expasy.org/images/Polyomaviridae_virion.jpg Polyomavirus Replicative Cycle Attachment and Entry ? Nucleus Major Histocompatibility Complex? RNA Pol II Large T Small T Polyomaviruses Genome Source: Poulin & DeCaprio, J. Clinical Oncology 24 (26) 4356-4365 (2006) Large T Antigen Functions Drives cells into S phase to provide the raw material needed for progeny virus production Initiates viral DNA replication Activates transcription from the late promoter Large T antigen Binds both pRB and p53 pRB (retinoblastoma protein): Tumor suppressor protein Prevents cell replication by by stalling cells in G1 phase Binds and inactivates the E2F transcription factor p53: Activate DNA repair proteins upon sensing DNA damage Induces growth arrest (Helps hold cells at the G1/S phase) Initiates apoptosis Suppression of pRB drives cells into S-phase Suppression of p53 prevents apoptosis VERY SIMILAR TO THE MECHANISM USED BY HPV TO CAUSE CANCER Large T Antigen Ini...
View Full Document

This document was uploaded on 01/26/2014.

Ask a homework question - tutors are online