Tula and Puumala hantavirus NSs ORFs are functional and the products inhibit activation of the interferon-beta promoter.
The S RNA genome segment of hantaviruses carried by Arvicolinae and Sigmodontinae rodents encodes the nucleocapsid (N) protein and has an overlapping (+1) open reading frame (ORF) for a putative nonstructural protein (NSs). The aim of this study was to determine whether the ORF is functional. A protein corresponding to the predicted size of Tula virus (TULV) NSs was detected using coupled in vitro transcription and translation from a cloned S segment cDNA, and a protein corresponding to the predicted size of Puumala virus (PUUV) NSs was detected in infected cells by Western blotting with an anti-peptide serum. The activities of the interferon beta (IFN-beta) promoter, and nuclear factor kappa B (NF-kappaB)- and interferon regulatory factor-3 (IRF-3) responsive promoters, were inhibited in COS-7 cells transiently expressing TULV or PUUV NSs. Also IFN-beta mRNA levels in IFN-competent MRC5 cells either infected with TULV or transiently expressing NSs were decreased. These data demonstrate that Tula and Puumala hantaviruses have a functional NSs ORF. The findings may explain why the NSs ORF has been preserved in the genome of most hantaviruses during their long evolution and why hantavirus-infected cells secrete relatively low levels of IFNs.
Jääskeläinen
Kirsi M
KM
Department of Virology, Haartman Institute, FIN-00014 University of Helsinki, Finland.
Kaukinen
Pasi
P
Minskaya
Ekaterina S
ES
Plyusnina
Angelina
A
Vapalahti
Olli
O
Elliott
Richard M
RM
Weber
Friedemann
F
Vaheri
Antti
A
Plyusnin
Alexander
A
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D015536:Down-Regulation; D006476:Orthohantavirus / Q000235:genetics*; D018778:Hantavirus Infections / Q000378:metabolism* / Q000821:virology; D006480:Hemorrhagic Fever with Renal Syndrome / Q000378:metabolism / Q000821:virology; D006801:Humans; D050838:Interferon Regulatory Factor-3 / Q000096:biosynthesis / Q000235:genetics; D016899:Interferon-beta / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000096:biosynthesis / Q000235:genetics; D019590:Nucleocapsid Proteins / Q000235:genetics*; D016366:Open Reading Frames / Q000502:physiology*; D011401:Promoter Regions, Genetic; D029262:Puumala virus / Q000235:genetics; D016415:Sequence Alignment; D017361:Viral Nonstructural Proteins / Q000502:physiology*
D050838:Interferon Regulatory Factor-3; D016328:NF-kappa B; D019590:Nucleocapsid Proteins; D017361:Viral Nonstructural Proteins; D016899:Interferon-beta