A critical proteolytic cleavage site near the C terminus of the yeast retrotransposon Ty1 Gag protein.

AUTOR(ES)

Merkulov, G V

RESUMO

Cleavage of the Gag and Gag-Pol polyprotein precursors is a critical step in proliferation of retroviruses and retroelements. The Ty1 retroelement of Saccharomyces cerevisiae forms virus-like particles (VLPs) made of the Gag protein. Ty1 Gag is not obviously homologous to the Gag proteins of retroviruses. The apparent molecular mass of Gag is reduced from 58 to 54 kDa during particle maturation. Antibodies raised against the C-terminal peptide of Gag react with the 58-kDa polypeptide but not with the 54-kDa one, indicating that Gag is proteolytically processed at the C terminus. A protease cleavage site between positions 401 and 402 of the Gag precursor was defined by carboxy-terminal sequencing of the processed form of Gag. Certain deletion and substitution mutations in the C terminus of the Gag precursor result in particles that are two-thirds the diameter of the wild-type VLPs. While the Ty1 protease is active in these mutants, their transposition rates are decreased 20-fold compared with that of wild-type Ty1. Thus, the Gag C-terminal portion, released in the course of particle maturation, probably plays a significant role in VLP morphogenesis and Ty1 transposition.

Documentos Relacionados

• Mapping the multimerization domains of the Gag protein of yeast retrotransposon Ty1.
• Rearrangements Occurring Adjacent to a Single Ty1 Yeast Retrotransposon in the Presence and Absence of Full-Length Ty1 Transcription
• Frameshift Signal Transplantation and the Unambiguous Analysis of Mutations in the Yeast Retrotransposon Ty1 Gag-Pol Overlap Region
• DNA synthesis fidelity by the reverse transcriptase of the yeast retrotransposon Ty1
• Yeast Ty1 retrotransposon: the minus-strand primer binding site and a cis-acting domain of the Ty1 RNA are both important for packaging of primer tRNA inside virus-like particles.