Related Experiment Videos
Synthesis of bacteriophage phi 29 proteins in Bacillus subtilis
Abstract:
Seventeen bacteriophage phi29 proteins were detected in ultraviolet light-irradiated Bacillus subtilis by autoradiography of polyacrylamide slab gels. The appearance of phi29 proteins occurred either before or concomitantly with viral DNA replication. Viral proteins detected early in the infectious cycle consisted of nine polypeptides ranging from 5,200 daltons to 54,000 daltons. Two of the early proteins were identified as, respectively, the major capsid protein and the protein comprising the filaments which extend from the head of the virus. Late phi29 proteins were composed of eight polypeptides ranging from 14,000 daltons to 95,000 daltons. Only three late proteins were noncapsid proteins. Among the early proteins, six were synthesized at diminishing rates late in the infectious cycle. One of the early proteins (protein 12) lacked histidine, whereas two (proteins 10 and 15) lacked tryptophan. Among the 17 proteins detected, 10 were viral noncapsid proteins. The amount of viral genetic information required to code for the 17 proteins detected in these experiments (81% of the potential genetic information of phi29 DNA) compares favorably with the genetic information detected as mRNA in a previous report, 85% of the potential information on the phi29 chromosome.
Insights
Researchers identified 17 bacteriophage phi29 proteins in Bacillus subtilis using autoradiography. These viral proteins appeared before or during DNA replication, with most genetic information coding for these essential viral components.
Area of Science:
- Microbiology
- Molecular Biology
- Virology
Background:
- Bacteriophage phi29 is a virus that infects Bacillus subtilis.
- Understanding the synthesis and function of viral proteins is crucial for comprehending the viral life cycle.
Purpose of the Study:
- To identify and characterize the proteins synthesized during bacteriophage phi29 infection of Bacillus subtilis.
- To determine the temporal appearance of these viral proteins in relation to viral DNA replication.
Main Methods:
- Autoradiography of polyacrylamide slab gels was used to detect bacteriophage phi29 proteins.
- Bacillus subtilis was infected with bacteriophage phi29 and irradiated with ultraviolet light.
Main Results:
- Seventeen bacteriophage phi29 proteins were detected, appearing before or concurrently with viral DNA replication.
- Early viral proteins included nine polypeptides, two identified as major capsid and head filament proteins.
- Late viral proteins comprised eight polypeptides, with only three being noncapsid proteins; ten out of seventeen detected proteins were noncapsid.
Conclusions:
- The study identified a significant number of bacteriophage phi29 proteins and their temporal expression during infection.
- The detected proteins account for a substantial portion of the bacteriophage phi29's genetic information, aligning with previous mRNA detection studies.