title: Identification of mutations causing temperature-sensitive defects in Semliki Forest virus RNA synthesis.
abstract: We have sequenced the nonstructural protein coding region of Semliki Forest virus temperature-sensitive (ts) mutant strains ts1, ts6, ts9, ts10, ts11, ts13, and ts14. In each case, the individual amino acid changes uncovered were transferred to the prototype strain background and thereby identified as the underlying cause of the altered RNA synthesis phenotype. All mutations mapping to the protease domain of nonstructural protein nsP2 caused defects in nonstructural polyprotein processing and subgenomic RNA synthesis, and all mutations in the helicase domain of nsP2 affected subgenomic RNA production. These types of defects were not associated with mutations in other nonstructural proteins.
authors.affiliation: Program in Cellular Biotechnology, Institute of Biotechnology, P.O. Box 56 (Viikinkaari 9), University of Helsinki, 00014 Helsinki, Finland.
authors.forename: Valeria
authors.initials: V
authors.lastname: Lulla
authors.forename: Andres
authors.initials: A
authors.lastname: Merits
authors.forename: Peter
authors.initials: P
authors.lastname: Sarin
authors.forename: Leevi
authors.initials: L
authors.lastname: Kääriäinen
authors.forename: Sirkka
authors.initials: S
authors.lastname: Keränen
authors.forename: Tero
authors.initials: T
authors.lastname: Ahola
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D012367:RNA, Viral / Q000096:biosynthesis* / Q000235:genetics; D011995:Recombination, Genetic; D012672:Semliki forest virus / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology; D013696:Temperature; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; D003546:Cysteine Endopeptidases; C078306:nsP2 proteinase