CHARACTERIZATION OF C-TERMINAL TRUNCATIONS OF THE GAG PRECURSOR PROTEIN OF MOLONEY MURINE LEUKEMIA VIRUS

Abstract

The retrovirus genome consists of three genes: gag, pol, and env. It has been known for some time that the env and poi gene products are not essential for the assembly of retrovirus particles. However, the gag precursor proteins are involved in this process. The exact mechanism by which these precursor proteins direct viral assembly still remains a mystery. In addition, the functional domains of the gag precursor involved in retroviral assembly have yet to be fully defined. In an attempt to further define these functional domains within the gag precursor protein, stop codons were created within the coding sequence for the gag precursor of Moloney Murine Leukemia Virus. The resulting truncated gag precursor proteins were then analyzed in an attempt to characterize these proteins. It was found that in mammalian cells, all of the truncated precursor proteins were expressed and released to the culture medium in a pelletable form. In addition, there appeared to be some sort of specificity for how efficiently these proteins were released. It was found that the last 17 amino acids of the gag precursor are non-essential for the formation of virus particles and the packaging of genomic viral RNA. The last 217 amino acids of the gag precursor protein are not necessary for the recognition and incorporation of the gag precursor protein into virus particles formed by 10A1 Murine Leukemia Virus wild type proteins.