In vitro packaging of bacteriophate T7 DNA synthesized in vitro.
AUTOR(ES)
Masker, W E
RESUMO
An in vitro DNA packaging system was used to encapsulate T7 DNA that had been synthesized by extracts prepared from gently lysed Escherchia coli infected with bacteriophage T7 carrying amber mutations in gene 3 or in both genes 3 and 6. Isopycnic centrifugation of density-labeled wild-type DNA was employed in an effort to separate product from template; suppressor-free indicator bacteria were used to eliminate contributions from endogenous DNA or contaminating phage. Additional controls indicated that fragmented DNA is packaged in vitro only with very low efficiency and that the frequency of recombination during packaging is too low to affect interpretation of these experiments. T7 DNA replicated by extracts prepared using T7 mutants deficient in both genes 3 and 6 could be packaged in vitro with an efficiency comparable to that found when highly purified virion T7 DNA was used. When T7 deficient in the gene 3 endonuclease but with normal levels of the gene 6 exonuclease was used, fast-sedimentingconcatemer-like DNA structures were formed during in vitro DNA synthesis. Electron microscopy revealed many branched and highly complex DNA structures formed during this reaction. This concatemer-like DNA was encapsulated in vitro with an efficiency significantly greater than that found for DNA the length of a single T7 genome.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=354148Documentos Relacionados
- Gene 2 protein of bacteriophage T7: purification and requirement for packaging of T7 DNA in vitro.
- In vitro packaging of bacteriophage T7 DNA requires ATP.
- Genetic recombination of bacteriophage T7 DNA in vitro.
- Packaging and Maturation of DNA of Bacteriophage T7 In Vitro
- DNA packaging in vitro by an isolated bacteriophage T7 procapsid.
