关键词:
Chromosome Deletion
Chromosome Deletion
Defective Viruses/genetics
Defective Viruses/isolation & purification
Genes, Viral
Genes, Viral
Models, Genetic
Nucleic Acid Heteroduplexes/genetics
Poliovirus/genetics
Poliovirus/isolation & purification
RNA, Viral/genetics
Viral Interference
Virus Replication
摘要:
An independent isolate of poliovirus defective interfering particles was analyzed. These particles, designated DI(A), are apparently analogous to the DI particles described by others. EM heteroduplex analysis reveals that the DI(A) isolate is a mixture of deletion mutants which changes with passage level. The DI(A) population consists of at least 5 distinct deletion mutants, including 1 double deletion. EM mapping of the deleted regions indicates that most, if not all, of the viral capsid region can be deleted. Despite this heterogeneity, the mutant genomes are quite similar in physical size. A model is proposed which suggests that the observed properties of poliovirus DI genomes reflect selective pressures extant during the amplification of the mutant genome. According to this model, only those deleted genomes which retain a minimal size and the capacity to synthesize a functional viral polymerase will replicate successfully in a mixed infection. This model proposes a mechanism for the enrichment of poliovirus DI genomes and an explanation for the low level of complementation observed in mixed infections of picornaviruses.