title: The 7a accessory protein of severe acute respiratory syndrome coronavirus acts as an RNA silencing suppressor.
abstract: RNA silencing suppressors (RSSs) are well studied for plant viruses but are not well defined to date for animal viruses. Here, we have identified an RSS from a medically important positive-sense mammalian virus, Severe acute respiratory syndrome coronavirus. The viral 7a accessory protein suppressed both transgene and virus-induced gene silencing by reducing the levels of small interfering RNA (siRNA). The suppression of silencing was analyzed by two independent assays, and the middle region (amino acids [aa] 32 to 89) of 7a was responsible for suppression. Finally, the RNA suppression property and the enhancement of heterologous replicon activity by the 7a protein were confirmed for animal cell lines.
authors.affiliation: Virology & Plant Molecular Biology Groups, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Road, New Delhi 110067, India.
authors.forename: Sumona
authors.initials: S
authors.lastname: Karjee
authors.forename: Ankita
authors.initials: A
authors.lastname: Minhas
authors.forename: Vikas
authors.initials: V
authors.lastname: Sood
authors.forename: Sanket S
authors.initials: SS
authors.lastname: Ponia
authors.forename: Akhil C
authors.initials: AC
authors.lastname: Banerjea
authors.forename: Vincent T K
authors.initials: VT
authors.lastname: Chow
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Mukherjee
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Lal
mesh_terms: D002460:Cell Line; D005814:Genes, Viral; D006801:Humans; D010942:Plant Viruses / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000821:virology; D034622:RNA Interference / Q000502:physiology*; D034741:RNA, Small Interfering / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology*; D013489:Suppression, Genetic; D014763:Viral Matrix Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*
chemical_list: D034741:RNA, Small Interfering; D012367:RNA, Viral; D014763:Viral Matrix Proteins; C488151:sars7a protein, SARS virus