title: In vivo functional characterization of the SARS-Coronavirus 3a protein in Drosophila.
abstract: The Severe Acute Respiratory Syndrome-Coronavirus (SARS-CoV) 3a locus encodes a 274 a.a. novel protein, and its expression has been confirmed in SARS patients. To study functional roles of 3a, we established a transgenic fly model for the SARS-CoV 3a gene. Misexpression of 3a in Drosophila caused a dominant rough eye phenotype. Using a specific monoclonal antibody, we demonstrated that the 3a protein displayed a punctate cytoplasmic localization in Drosophila as in SARS-CoV-infected cells. We provide genetic evidence to support that 3a is functionally related to clathrin-mediated endocytosis. We further found that 3a misexpression induces apoptosis, which could be modulated by cellular cytochrome c levels and caspase activity. From a forward genetic screen, 78 dominant 3a modifying loci were recovered and the identity of these modifiers revealed that the severity of the 3a-induced rough eye phenotype depends on multiple cellular processes including gene transcriptional regulation.
authors.affiliation: Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, NT, China.
authors.forename: S L Alan
authors.initials: SL
authors.lastname: Wong
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Chen
authors.forename: Chak Ming
authors.initials: CM
authors.lastname: Chan
authors.forename: C S Michael
authors.initials: CS
authors.lastname: Chan
authors.forename: Paul K S
authors.initials: PK
authors.lastname: Chan
authors.forename: Y L
authors.initials: YL
authors.lastname: Chui
authors.forename: Kwok Pui
authors.initials: KP
authors.lastname: Fung
authors.forename: Mary M Y
authors.initials: MM
authors.lastname: Waye
authors.forename: Stephen K W
authors.initials: SK
authors.lastname: Tsui
authors.forename: H Y Edwin
authors.initials: HY
authors.lastname: Chan
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000911:Antibodies, Monoclonal / Q000276:immunology; D002966:Clathrin / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004330:Drosophila / Q000235:genetics; D004705:Endocytosis; D018014:Gene Transfer Techniques; D006801:Humans; D010641:Phenotype; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics*; D014759:Viral Envelope Proteins; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D000086082:Viroporin Proteins
chemical_list: C487105:3a protein, SARS-CoV; D000911:Antibodies, Monoclonal; D002966:Clathrin; D014759:Viral Envelope Proteins; D014764:Viral Proteins; D000086082:Viroporin Proteins