Assemblages of simian virus 40 capsid proteins and viral DNA visualized by electron microscopy

SV40 assembles in the nucleus by addition of capsid proteins to the minichromosome. The VP1 5VP2/3 capsomer is composed of a pentamer of the major protein VP1 complexed with a monomer of a minor protein, VP2 or VP3. In the capsid, the capsomers are bound together via their flexible carboxy-terminal...

Full description

Saved in:
Bibliographic Details
Published in:Biochemical and biophysical research communications 2007-02, Vol.353 (2), p.424-430
Main Authors: Roitman-Shemer, Vered, Stokrova, Jitka, Forstova, Jitka, Oppenheim, Ariella
Format: Article
Language:English
Subjects:
60 APPLIED LIFE SCIENCES
Binding Sites
Capsid proteins
Capsid Proteins - chemistry
Capsid Proteins - ultrastructure
CELL NUCLEI
CHROMATIN
DNA
DNA spreads
DNA, Viral - chemistry
DNA, Viral - ultrastructure
ELECTRON MICROSCOPY
IN VITRO
Macromolecular Substances - chemistry
Microscopy, Electron
Molecular Conformation
MONOMERS
MUTANTS
Protein Binding
PROTEINS
Protein–DNA interactions
SIMIAN VIRUS
Simian virus 40
Simian virus 40 - chemistry
Simian virus 40 - ultrastructure
SV40
Virus Assembly
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:SV40 assembles in the nucleus by addition of capsid proteins to the minichromosome. The VP1 5VP2/3 capsomer is composed of a pentamer of the major protein VP1 complexed with a monomer of a minor protein, VP2 or VP3. In the capsid, the capsomers are bound together via their flexible carboxy-terminal arms. Our previous studies suggested that the capsomers are recruited to the packaging signal ses via avid interaction with Sp1. During assembly Sp1 is displaced, allowing chromatin compaction. Here we investigated the interactions in vitro of VP1 5VP2/3 capsomers with the entire SV40 genome, using mutant VP1 deleted in the carboxy-arm that cannot assemble, but retains DNA-binding capacity. EM revealed that VP1 5VP2/3 complexes bind non-specifically at random locations around the DNA. Sp1 was absent from mature virions. The findings suggest that multiple capsomers attach simultaneously to the viral genome, increasing their local concentration, facilitating rapid, concerted assembly reaction and removal of Sp1.
ISSN:0006-291X
1090-2104
DOI:10.1016/j.bbrc.2006.12.038