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Injection defect in alkylated and depurinated T7 bacteriophage: analysis by DNA ejection
Canadian Journal of Biochemistry
|March 1, 1982
Summary
Alkylation and depurination cause defects in T7 bacteriophage DNA injection. DNA was partially ejected from both modified phages, starting from the genetic left end, confirming previous findings.
Area of Science:
- Molecular Biology
- Virology
- Biochemistry
Background:
- T7 bacteriophage is a model organism for studying DNA injection mechanisms.
- DNA injection is a critical step in bacteriophage infection.
- Previous studies have documented DNA injection defects in T7 phage.
Purpose of the Study:
- To investigate the DNA injection defect in T7 bacteriophage caused by alkylation and depurination.
- To determine the mechanism and direction of DNA ejection in modified T7 phage.
Main Methods:
- In vitro DNA ejection model using formamide treatment.
- Alkylation of T7 phage with methyl methanesulfonate.
- Induction of depurination by incubation.
- Analysis of phage preparations using electron microscopy.
- Measurement of DNA lengths and phage head fullness.
- Binding of E. coli RNA polymerase to determine DNA ejection direction.
Main Results:
- Both alkylated and depurinated T7 phages exhibited partial DNA ejection.
- DNA ejection initiated from the genetic left end of the phage.
- RNA polymerase binding confirmed the starting point of ejection in alkylated phage.
Conclusions:
- Alkylation leads to partial DNA injection in T7 phage, originating from the genetic left end.
- Partial DNA injection is likely responsible for the observed injection defect in depurinated T7 phage.