Related Experiment Videos
Early synthesis of membrane protein after bacteriophage T4 infection
Abstract:
Proteins that associate with cellular membrane during the first 5 min after infection with bacteriophage T4 were examined. Several procedures, including electrophoretic separations in three sodium dodecyl sulfate polyacrylamide gel systems and inhibition of host protein synthesis by UV irradiation, were employed to distinguish host-specified proteins from those induced by T4. Residual host protein synthesis was found to account for much of the new protein in preparations of the total membrane and for almost all of the newly synthesized protein in the outer membrane. Preliminary evidence indicates that the synthesis of some host membrane proteins is shut off less rapidly than is host synthesis of soluble protein. One host-directed polypeptide of the outer membrane was unique in that its synthesis or incorporation into the membrane was preferentially inhibited by infection. Also, it was found that the detergent Sarkosyl solubilizes all early T4 membrane proteins; this observation provides the basis for a simple procedure for distinguishing phage proteins from host outer membrane proteins.
Insights
Bacteriophage T4 infection primarily uses host proteins in the cellular membrane, especially the outer membrane, not T4-induced proteins. A new method using Sarkosyl detergent distinguishes these proteins.
Area of Science:
- Molecular Biology
- Virology
- Cellular Biology
Background:
- Bacteriophage T4 infection rapidly alters host cell processes.
- Understanding early viral-host interactions at the membrane level is crucial.
Purpose of the Study:
- To identify and characterize host- and phage-specific proteins in the cellular membrane within 5 minutes of bacteriophage T4 infection.
- To differentiate early T4-induced membrane proteins from residual host proteins.
Main Methods:
- Electrophoretic separation using three SDS-PAGE systems.
- UV irradiation to inhibit host protein synthesis.
- Differential solubility in Sarkosyl detergent.
Main Results:
- Residual host protein synthesis significantly contributes to newly synthesized membrane proteins, particularly in the outer membrane.
- Host membrane protein synthesis shutoff is slower than soluble protein synthesis.
- One host outer membrane polypeptide's synthesis/incorporation is preferentially inhibited post-infection.
- Sarkosyl detergent effectively solubilizes all early T4 membrane proteins.
Conclusions:
- Early bacteriophage T4 infection relies heavily on pre-existing host membrane proteins.
- A Sarkosyl-based method provides a straightforward way to distinguish phage from host outer membrane proteins.