Abstract
A respiratory disease caused by a novel coronavirus, termed the severe acute respiratory syndrome coronavirus (SARS-CoV), was first reported in China in late 2002. The subsequent efficient human-to-human transmission of this virus eventually affected more than 30 countries worldwide, resulting in a mortality rate of ~10% of infected individuals. The spread of the virus was ultimately controlled by isolation of infected individuals and there has been no infections reported since April 2004. However, the natural reservoir of the virus was never identified and it is not known if this virus will re-emerge and, therefore, research on this virus continues. The SARS-CoV genome is about 30 kb in length and is predicted to contain 14 functional open reading frames (ORFs). The genome encodes for proteins that are homologous to known coronavirus proteins, such as the replicase proteins (ORFs 1a and 1b) and the four major structural proteins: nucleocapsid (N), spike (S), membrane (M) and envelope (E). SARS-CoV also encodes for eight unique proteins, called accessory proteins, with no known homologues. This review will summarize the current knowledge on SARS-CoV accessory proteins and will include: (i) expression and processing; (ii) the effects on cellular processes; and (iii) functional studies.
Highlights
Prior to the outbreak of severe acute respiratory syndrome (SARS) caused by SARS human coronavirus (HCoV) in 2003 [1,2,3], only two human coronaviruses, HCoV-OC43 and HCoV-229E, were known [4,5]
Viruses generally encode for: (i) proteins functioning in the replication and transcription of the viral genome; (ii) structural proteins of the virion; and (iii) accessory proteins that enable, facilitate or modulate the infection process
These accessory proteins normally act by interfering with cellular processes or by modulating virus-host interactions at the level of the organism (Table 1)
Summary
Prior to the outbreak of severe acute respiratory syndrome (SARS) caused by SARS human coronavirus (HCoV) in 2003 [1,2,3], only two human coronaviruses, HCoV-OC43 and HCoV-229E, were known [4,5]. In addition to the replicase and structural open reading frames (ORFs), the SARS-CoV genome contains eight ORFs encoding for accessory proteins with no known homologues (Figure 1). These group-specific accessory proteins are interspersed among the structural genes at the 3’-end of the genome. Reports to date make it clear that the CoV accessory proteins are not essential for virus replication in vitro, but since these genes are maintained in the virus genomes under selective pressures, they have to confer a biological advantage to the virus in the natural environment of the infected host [20]. In this review the current knowledge on SARS-CoV accessory proteins (ORFs 3a, 3b, 6, 7a, 7b, 8a, 8b and 9b) will be summarized and will include: (i) expression and processing; (ii) the effects on cellular processes; and (iii) functional studies
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
