Negative Strand RNA Synthesis by Temperature-Sensitive Mutants of Mouse Hepatitis Virus

  • D. R. Younker
  • S. G. Sawicki
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 440)


Mutants of the A59 strain of mouse hepatitis virus (MHV) were studied to determine the effects of temperature shift on negative and positive strand RNA synthesis. Mutant LA 9 was originally reported to have a selective temperature sensitive defect in negative strand synthesis. We found that this mutant continued to synthesize negative strands for at least one hour after temperature shift. LA 6 was found to possess a temperature sensitive defect in negative strand synthesis. Following temperature shift, negative strand synthesis rapidly declined. The effect of temperature shift on negative strand synthesis by LA 6 was similar to the effect of cycloheximide treatment of the parental A59 virus. Temperature shift of Alb 16 infected cells did not stop negative strand synthesis but did prevent a corresponding rise in the rate of positive strand synthesis. Therefore, we suggest that Alb 16 is a conversion mutant because it cannot convert newly synthesized negative strands into templates for positive strand synthesis at the nonpermissive temperature.


Temperature Shift Pulse Period Strand Synthesis Virus Yield Nonpermissive Temperature 
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Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • D. R. Younker
    • 1
  • S. G. Sawicki
    • 1
  1. 1.Department of Microbiology and ImmunologyMedical College of OhioToledoUSA

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