Nucleotide sequence heterogeneity of an RNA phage population
1978; Cell Press; Volume: 13; Issue: 4 Linguagem: Inglês
10.1016/0092-8674(78)90223-4
ISSN1097-4172
AutoresEsteban Domingo, Donna L. Sabo, Tadatsugu Taniguchi, Charles Weissmann,
Tópico(s)Genomics and Phylogenetic Studies
ResumoThe nucleotide sequence of 32P-RNA from Qβ phage clones was sampled by two-dimensional polyacrylamide gel electrophoresis of the RNAase T1-resistant oligonucleotides (T1 fingerprinting). About 15% of the clones derived from a multiply passaged Qβ population showed fingerprint patterns which deviated from that of the RNA from the total population. All deviations examined could be attributed to one and, less frequently, to two or more nucleotide transitions. Since the fingerprinting technique allows the analysis of only about 10% of the RNA sequence, we estimate that each viable phage genome in a multiply passaged population differs in one to two positions from the "average" sequence of the parental population. Several deviant clones were tested by growth competition against a "wild-type" population; after 10–20 generations, the resulting phage showed the "wild-type" T1 fingerprint pattern. We propose that a Qβ phage population is in a dynamic equilibrium, with viable mutants arising at a high rate ( Batschelet et al., 1976 Batschelet E. Domingo E. Weissmann C. The proportion of revertant and mutant phage in a growing population, as a function of mutation and growth rate. Gene. 1976; 1: 27-32 Crossref PubMed Scopus (157) Google Scholar ; Domingo et al., 1976 Domingo E. Flavell R.A. Weissmann C. In vitro site-directed mutagenesis: generation and properties of an infectous extracistronic mutant of bacteriophage Qβ. Gene. 1976; 1: 3-25 Crossref PubMed Scopus (73) Google Scholar ) on the one hand, and being strongly selected against on the other. The genome of Qβ phage cannot be described as a defined unique structure, but rather as a weighted average of a large number of different individual sequences.
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