Substitution or deletion mutations between nt 54 and 70 in the 5' non-coding region of dengue type 2 virus produce variable effects on virus viability.
A C57U nucleotide mutation in a predicted RNA stem structure (nt 11-16/56-61) of the 5' non-coding region (5'NCR) of dengue 2 (DEN-2) 16681 virus is partially attenuating, but unstable during serial passage of certain candidate DEN-2 PDK-53-based vaccine viruses containing this mutation. Here, 11 different mutations (one or more point substitution and/or deletion) between nt 54 and 70 in the 5'NCR of the pD2/IC-30P-A (16681) infectious clone are described. Four mutants were infectious. Three mutants with single point substitutions replicated well in cell culture and exhibited variable neurovirulence in mice. Constructs containing multiple substitutions or any deletions failed to produce infectious viruses. Unexpectedly, a double C57U+G58C mutant replicated as efficiently as D2/IC-30P-A virus, and was more neurovirulent for newborn ICR mice. Thus, despite its predicted additional disruption of the RNA stem structure, the engineered contiguous secondary G58C mutation caused reversion of the partially attenuated phenotype caused by the 5'NCR-C57U mutation.
Sirigulpanit
Wipawan
W
Department of Anatomy and Center for Vectors and Vector-Borne Diseases, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
Kinney
Richard M
RM
Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, US Department of Health and Human Services, Public Health Service, Fort Collins, CO 80522, USA.
Leardkamolkarn
Vijittra
V
Department of Anatomy and Center for Vectors and Vector-Borne Diseases, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
D020121:5' Untranslated Regions; D000818:Animals; D002460:Cell Line; D009033:Culicidae; D003715:Dengue / Q000821:virology; D003716:Dengue Virus / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D004195:Disease Models, Animal; D008253:Macaca mulatta; D051379:Mice; D008813:Mice, Inbred ICR; D050296:Microbial Viability / Q000235:genetics*; D009690:Nucleic Acid Conformation; D017354:Point Mutation; D012367:RNA, Viral / Q000235:genetics; D017384:Sequence Deletion; D014774:Virulence / Q000235:genetics; D014779:Virus Replication / Q000235:genetics; D014780:Viruses
D020121:5' Untranslated Regions; D012367:RNA, Viral