Localization of self-interacting domains within betaretrovirus Gag polyproteins.
The Betaretrovirus genus is characterized by the ability to preassemble immature capsids within the cytoplasm. For Mason-Pfizer monkey virus (M-PMV) this ability depends in part upon the unique Internal Scaffold Domain (ISD) within the p12 region of Gag. In this study, we have further characterized the ability of M-PMV p12 to promote Gag-Gag interaction and have examined the Gag polyprotein of the related mouse mammary tumor virus (MMTV) to potentially identify a region with equivalent function. Using the yeast two-hybrid system, we confirmed that both Gag polyproteins strongly interact, primarily through the CA-NC regions, but also through additional domains N-terminal to CA. For M-PMV, this auxiliary interaction domain was p12. For MMTV, no single strongly self-interacting protein was identified. Instead, MMTV Gag appears to utilize the weak contributions of several protein domains to support the main interaction of its CA-NC. Our findings suggest that, in addition to the canonical NC "I-domain" interaction, MMTV Gag self-association results from the concerted action of multiple regions of the polyprotein while M-PMV Gag relies mainly on its p12 domain.
Zábranský
Ales
A
Department of Protein Biochemistry, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo n.2, Prague 6, 16610, Czech Republic. ales@uochb.cas.cz
Sakalian
Michael
M
Pichová
Iva
I
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002213:Capsid; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics; D015683:Gene Products, gag / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics / Q000378:metabolism; D016093:Mason-Pfizer monkey virus / Q000378:metabolism*; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction
D017931:DNA Primers; D015683:Gene Products, gag