Temperature-sensitive virus from Aedes albopictus cells chronically infected with Sindbis virus

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Persistent Sindbis virus (SV-W) infections in Aedes albopictus cells can lead to viral evolution.
• Understanding viral adaptation and mutation is crucial for controlling arbovirus infections.

Purpose of the Study:

• To characterize small plaque-forming, temperature-sensitive mutants (SV-C) derived from persistent Sindbis virus infections.
• To investigate the genetic and phenotypic properties of these SV-C mutants.

Main Methods:

• Isolation and plaque purification of temperature-sensitive (ts) mutant clones from SV-C.
• Serial undiluted passage of mutant clones in cell cultures (BHK and mosquito cells).
• RNA synthesis assays and thermal inactivation studies.

Main Results:

• SV-C mutants were identified as small plaque formers and temperature-sensitive.
• Revertants (ts(+)) retaining mutant plaque morphology arose after serial passage.
• Nineteen of twenty SV-C clones were RNA-positive (RNA+), with one clone (SV-C-2) being RNA-negative (RNA-).
• RNA synthesis induced by SV-C-2 remained stable at non-permissive temperatures.
• SV-C clones showed increased thermal lability compared to SV-W.
• No complementation was observed between SV-C clones.

Conclusions:

• Persistent Sindbis virus infection drives the emergence of specific mutant strains with altered properties.
• These mutants exhibit distinct characteristics in plaque formation, temperature sensitivity, and RNA synthesis.
• The observed genetic instability and lack of complementation suggest complex evolutionary pathways for Sindbis virus in persistent infections.