characterization of conditionally lethal mutants of alphaviruses , sindbis virus and semliki forest virus , has indicated that in almost all the rna-negative mutants the temperature-sensitive ( ts ) defect prevents the formation of active transcription complexes at nonpermissive temperature ( 40 degrees c ) , but such complexes retain activity at 40 degrees c if formed first at permissive temperature ( 30 degrees c ) .
C0035668
rna
C0040649
transcription