title: The severe acute respiratory syndrome coronavirus 3a is a novel structural protein.
abstract: The severe acute respiratory syndrome coronavirus (SARS-CoV) 3a protein is one of the opening reading frames in the viral genome with no homologue in other known coronaviruses. Expression of the 3a protein has been demonstrated during both in vitro and in vivo infection. Here we present biochemical data to show that 3a is a novel coronavirus structural protein. 3a was detected in virions purified from SARS-CoV infected Vero E6 cells although two truncated products were present predominantly instead of the full-length protein. In Vero E6 cells transiently transfected with a cDNA construct for expressing 3a, a similar cleavage was observed. Furthermore, co-expression of 3a, membrane and envelope proteins using the baculovirus system showed that both full-length and truncated 3a can be assembled into virus-like particles. This is the first report that demonstrated the incorporation of 3a into virion and showed that the SARS-CoV encodes a novel coronavirus structural protein.
authors.affiliation: Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore.
authors.forename: Shuo
authors.initials: S
authors.lastname: Shen
authors.forename: Pi-Shiu
authors.initials: PS
authors.lastname: Lin
authors.forename: Yu-Chan
authors.initials: YC
authors.lastname: Chao
authors.forename: Aihua
authors.initials: A
authors.lastname: Zhang
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Yang
authors.forename: Seng Gee
authors.initials: SG
authors.lastname: Lim
authors.forename: Wanjin
authors.initials: W
authors.lastname: Hong
authors.forename: Yee-Joo
authors.initials: YJ
authors.lastname: Tan
mesh_terms: D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D002522:Chlorocebus aethiops; D018076:DNA, Complementary; D016366:Open Reading Frames; D010957:Plasmids; D011995:Recombination, Genetic; D014709:Vero Cells; D014759:Viral Envelope Proteins; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*; D015678:Viral Structural Proteins / Q000737:chemistry / Q000378:metabolism*; D000086082:Viroporin Proteins
chemical_list: C487105:3a protein, SARS-CoV; D018076:DNA, Complementary; D014759:Viral Envelope Proteins; D014764:Viral Proteins; D015678:Viral Structural Proteins; D000086082:Viroporin Proteins