Two-hybrid analysis of Ty3 capsid subdomain interactions.
BACKGROUND
The yeast retrotransposon Ty3 forms stable virus-like particles. Gag3, the major structural protein, is composed of capsid, spacer and nucleocapsid domains. The capsid domain of Gag3 was previously modeled as a structure similar to retrovirus capsid.


RESULTS
Two-hybrid analysis was used to understand the interactions that contribute to particle assembly. Gag3 interacted with itself as predicted based on its role as the major structural protein. The N-terminal subdomain (NTD) of the capsid was able to interact with itself and with the C-terminal subdomain (CTD) of the capsid, but interacted less well with intact Gag3. Mutations previously shown to block particle assembly disrupted Gag3 interactions more than subdomain interactions.


CONCLUSIONS
The findings that the NTD interacts with itself and with the CTD are consistent with previous modeling and a role similar to that of the capsid in retrovirus particle structure. These results are consistent with a model in which the Gag3-Gag3 interactions that initiate assembly differ from the subdomain interactions that potentially underlie particle stability.
Zhang
Min
M
Department of Biological Chemistry, University of California, Irvine, CA, USA.
Larsen
Liza Sz
LS
Department of Biological Chemistry, University of California, Irvine, CA, USA.
Irwin
Becky
B
Department of Biological Chemistry, University of California, Irvine, CA, USA.
Bilanchone
Virginia
V
Department of Biological Chemistry, University of California, Irvine, CA, USA.
Sandmeyer
Suzanne
S
Department of Biological Chemistry, University of California, Irvine, CA, USA.|Department of Microbiology and Molecular Genetics, University of California, Irvine, CA, USA.|Institute for Genomics and Bioinformatics, University of California, Irvine, CA, USA.
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