Analysis of mutations in the integration function of Moloney murine leukemia virus: effects on DNA binding and cutting.

摘要: The 3' terminus of the pol gene Moloney murine leukemia virus encodes integration (IN) protein, required for establishment integrated provirus. A series six linker insertion mutations and two single-base substitutions were generated within region encoding IN protein. Mutations initially an Escherichia coli plasmid expressing resulting variants assayed DNA-binding activity. which altered conserved cysteine residues a potential DNA finger-binding motif resulted in lower or variable binding, appeared to be result protein folding. Upon renaturation, these proteins able nonspecifically bind manner similar that other mutant parent. When reconstructed back into full-length virus, seven eight lethal. All mutants produced stable virions mediated normal conversion retroviral RNA its three forms. Fine-structure analysis linear double-stranded viral indicated all lethal alterations blocked formation recessed termini normally precedes integration.