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In vitro assembly of virus-like particles of a Gammaretrovirus (XMRV)

Jemal

Senior Member
Messages
1,031
I have no idea what it means...

Immature retroviral particles are assembled by self-association of the structural polyprotein precursor Gag. During maturation the Gag polyprotein is proteolytically cleaved yielding mature structural proteins: matrix (MA), capsid (CA) and nucleocapsid (NC) that re-assemble into a mature viral particle. Proteolytic cleavage causes the N-terminus of CA to fold back to form a ?-hairpin, anchored by an internal salt bridge between the N-terminal proline and inner aspartate. Using an in vitro assembly system of capsid-nucleocapsid protein (CANC), we studied formation of virus-like particles (VLP) of a Gammaretrovirus, the xenotropic murine leukemia virus (MLV)-related virus (XMRV). We show here that unlike for other retroviruses, XMRV CA and CANC do not assemble tubular particles characteristic of mature assembly. The prevention of the ?-hairpin formation, either by the deletion of the N-terminal proline or ten initial amino acids enabled the assembly of ?ProCANC or ?10CANC into immature-like, spherical particles. Detailed 3D structural analysis of these particles revealed that below a disordered N-terminal CA layer the C-terminus of CA assembles a typical immature lattice, which is linked by rod-like densities with the RNP.

http://jvi.asm.org/content/early/2011/11/09/JVI.05564-11.abstract?related-urls=yes&legid=jvi;JVI.05564-11v1
 

Tony Mach

Show me the evidence.
Messages
146
Location
Upper Palatinate, Bavaria
As far as I understand, they studied how the individual pieces of a XMRV virus ("structural proteins") fall together ("are assembled") to form virus-like particles (I guess either incomplete viruses or a intermediate step to a full virus but I could be wrong). They seem to have found differences in the assembly to other Gammaretroviruses whether these differences are big or subtle, I can't tell.

If XMRV were a human pathogen, this could offer clues how to block this step in virus formation. As it stands, XMRV is not a human pathogen so this only helps further the understanding of viruses in general.
 

Bob

Senior Member
Messages
16,455
Location
England (south coast)
I'm not sure exactly what it means either. Like Tony said, it seems to be exploring the way that immature viral particles combine to form mature viruses. But I can't work out what the significance might be from reading only this abstract.
 

Enid

Senior Member
Messages
3,309
Location
UK
Whatever it does mean, it is good to see advances in the understanding of viral behaviours going on. (I'm not a scientist though).