Matrix protein of Akv murine leukemia virus: genetic mapping of regions essential for particle formation.
Type C retroviruses assemble at the plasma membrane of the infected cell. Attachment of myristic acid to the N terminus of the Gag precursor polyprotein has been shown to be essential for membrane localization and virus morphogenesis. Here, we report that the matrix (MA) protein contains regions that in conjunction with myristylation are important for Gag protein stability and the assembly of murine leukemia viruses. We identified these domains by generating a series of Akv murine leukemia virus mutants carrying small in-frame deletions within the coding region of the MA protein encompassing 129 amino acids. Studies show that mutants with deletions within the segment encoding the first 102 amino acids were all replication defective, whereas the C-terminal residues 103 to 124 seem not to have any critical function in virus maturation. Cells expressing the replication-defective genomes did not release any detectable Gag proteins. In one mutant, deletion of 3 amino acids in the N terminus resulted in an inefficiently myristylated, stable Gag polyprotein. The remaining defect genomes encoded unstable Gag proteins, although they were modified with myristic acid. The results suggest that the matrix domain plays an important role in stabilizing the Gag polyprotein.
Jørgensen
E C
EC
Department of Molecular Biology, University of Aarhus, Denmark.
Pedersen
F S
FS
Jørgensen
P
P
D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004261:DNA Replication; D004279:DNA, Viral; D015683:Gene Products, gag / Q000378:metabolism; D005814:Genes, Viral; D005816:Genetic Complementation Test; D007700:Kinetics; D009052:Leukemia Virus, Murine / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism; D011533:Proviruses / Q000235:genetics; D016415:Sequence Alignment; D014158:Transcription, Genetic; D014763:Viral Matrix Proteins / Q000235:genetics*
D004279:DNA, Viral; D015683:Gene Products, gag; D009227:Myristic Acids; D014763:Viral Matrix Proteins; D019814:Myristic Acid