The human severe acute respiratory syndrome coronavirus (SARS-CoV) 8b protein is distinct from its counterpart in animal SARS-CoV and down-regulates the expression of the envelope protein in infected cells.
The severe acute respiratory syndrome coronavirus (SARS-CoV), isolated from humans infected during the peak of epidemic, encodes two accessory proteins termed as 8a and 8b. Interestingly, the SARS-CoV isolated from animals contains an extra 29-nucleotide in this region such that these proteins are fused to become a single protein, 8ab. Here, we compared the cellular properties of the 8a, 8b and 8ab proteins by examining their cellular localizations and their abilities to interact with other SARS-CoV proteins. These results may suggest that the conformations of 8a and 8b are different from 8ab although nearly all the amino acids in 8a and 8b are found in 8ab. In addition, the expression of the structural protein, envelope (E), was down-regulated by 8b but not 8a or 8ab. Consequently, E was not detectable in SARS-CoV-infected cells that were expressing high levels of 8b. These findings suggest that 8b may modulate viral replication and/or pathogenesis.
Keng
Choong-Tat
CT
Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore, 138673.
Choi
Yook-Wah
YW
Welkers
Matthijs R A
MR
Chan
Daphne Z L
DZ
Shen
Shuo
S
Gee Lim
Seng
S
Hong
Wanjin
W
Tan
Yee-Joo
YJ
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000737:chemistry; D015967:Gene Expression Regulation, Viral; D006801:Humans; D047468:Immunoprecipitation; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D011485:Protein Binding; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics* / Q000502:physiology*; D014158:Transcription, Genetic; D014759:Viral Envelope Proteins / Q000032:analysis / Q000096:biosynthesis*; D014763:Viral Matrix Proteins / Q000032:analysis / Q000235:genetics* / Q000502:physiology*; D014764:Viral Proteins / Q000032:analysis / Q000235:genetics* / Q000502:physiology*; D000086082:Viroporin Proteins
C501689:E protein, SARS coronavirus; D012333:RNA, Messenger; D012367:RNA, Viral; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; D014764:Viral Proteins; D000086082:Viroporin Proteins; C488151:sars7a protein, SARS virus