Related Experiment Videos
Temperature-sensitive RNA polymerase mutants of a picornavirus
Abstract:
Temperature-sensitive (ts) RNA polymerase mutants of a picornavirus are reported. Two foot-and-mouth disease virus (FMDV) mutants designated ts 22 and ts 115 have been characterized. As judged by isoelectric focusing, both have charge alterations in P56a, the FMDV RNA polymerase protein. Virus RNA synthesis in cells infected with the mutants is severely impaired at the nonpermissive temperature. RNA polymerase purified from baby hamster kidney cells infected with these mutants exhibits a marked ts transcribing activity in vitro. Spontaneous revertants of both mutants have P56a polypeptides that are indistinguishable from the parental proteins on the basis of charge. The revertants regain the ability to synthesize virus RNA in vivo at the nonpermissive temperature. RNA polymerase purified from the revertants remains transcriptionally active at the nonpermissive temperature.
Insights
Temperature-sensitive (ts) RNA polymerase mutants were created for foot-and-mouth disease virus (FMDV). These mutants showed impaired RNA synthesis, confirming the RNA polymerase
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- Picornaviruses, including foot-and-mouth disease virus (FMDV), rely on RNA-dependent RNA polymerase for replication.
- Understanding the structure-function relationship of viral RNA polymerase is crucial for developing antiviral strategies.
Purpose of the Study:
- To characterize temperature-sensitive (ts) mutants of FMDV RNA polymerase.
- To investigate the role of specific alterations in the FMDV RNA polymerase (P56a) in viral RNA synthesis.
Main Methods:
- Generation and characterization of temperature-sensitive (ts) FMDV mutants (ts 22 and ts 115).
- Isoelectric focusing to analyze charge alterations in the P56a protein.
- In vitro transcription assays using purified RNA polymerase.
- Analysis of spontaneous revertants to confirm genetic linkage.
Main Results:
- Two ts mutants, ts 22 and ts 115, exhibited charge alterations in the P56a RNA polymerase protein.
- Viral RNA synthesis was significantly impaired in cells infected with these mutants at the nonpermissive temperature.
- Purified mutant RNA polymerase showed temperature-sensitive transcribing activity in vitro.
- Revertants restored RNA synthesis and possessed normal P56a polypeptides, indicating the mutations were responsible.
Conclusions:
- Temperature-sensitive mutations in the FMDV P56a RNA polymerase affect its enzymatic activity.
- Specific charge alterations in the RNA polymerase are critical for viral RNA synthesis in FMDV.
- These findings provide insights into the molecular mechanisms of picornavirus RNA replication.