Browsing Research Articles (Medical Bioscience) by Title
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Now showing items 12-17 of 17
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Khan, Sehaam; Fielding, Burtram C.; Tan, Timothy. H.P.; Chou, Chih-Fong; Shou, Shen; Lim, Seng Gee; Hong, Wanjin; Tan, Yee-Joo (Elsevier, 2006)[more][less]
Abstract: The genome of the severe acute respiratory syndrome coronavirus encodes for eight accessory viral proteins with no known homologues in other coronaviruses. One of these is the 3b protein, which is encoded by the second open reading frame in subgenomic RNA 3 and contains 154 amino acids. Here, a detailed time-course study was performed to compare the apoptosis and necrosis profiles induced by full-length 3b, a 3b mutant that was deleted by 30 amino acids from the C terminus (3b 124-154) and the classical apoptosis inducer, Bax. Our results showed that Vero E6 cells transfected with a construct for expressing 3b underwent necrosis as early as 6 h after transfection and underwent simultaneous necrosis and apoptosis at later time-points. At all the time-points analysed, the apoptosis induced by the expression of 3b was less than the level induced by Bax but the level of necrosis was comparable. The 3b 124-154 mutant behaves in a similar manner indicating that the localization of the 3b protein does not seems to be important for the cell-death pathways since full-length 3b is localized predominantly to the nucleolus, while the mutant is found to be concentrated in the peri-nuclear regions. To our knowledge, this is the first report of the induction of necrosis by a SARS-CoV protein. URI: http://hdl.handle.net/10566/884 Files in this item: 0
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Tan, Yee-Joo; Goh, Phuay-Yee; Fielding, Burtram C.; Shen, Shou; Chou, Chih-Fong; Fu, Jian-Lin; Leong, Hoe Nam; Leo, Yee Sin; Ooi, Eng Eong; Ling, Ai Ee; Lim, Seng Gee; Hong, Wanjin (American Society for Microbiology, 2004)[more][less]
URI: http://hdl.handle.net/10566/880 Files in this item: 1
TanAcuteRespiratorySyndrome2004.pdf (1.622Mb) -
Tan, Yee-Joo; Tham, Puay-Yoke; Chan, Daphne Z. L.; Chou, Chih-Fong; Shen, Shou; Fielding, Burtram C.; Tan, Timothy. H.P.; Lim, Seng Gee; Hong, Wanjin (2005)[more][less]
Abstract: Here we analyzed the gene expression profile of cells that stably express the severe acute respiratory syndrome coronavirus (SARS-CoV) 3a protein to determine its effects on host functions. A lung epithelial cell-line, A549, was chosen for this study because the lung is the primary organ infected by SARS-CoV and fatalities resulted mainly from pulmonary complications. Our results showed that the expression of 3a up-regulates the mRNA levels of all three subunits, A , B , and , of fibrinogen. Consequently, the intracellular levels as well as the secretion of fibrinogen were increased. We also observed increased fibrinogen levels in SARS-CoV-infected Vero E6 cells. URI: http://hdl.handle.net/10566/883 Files in this item: 1
TanYJ-J Virol-Aug2005.pdf (122.8Kb) -
Fielding, Burtram C.; Gunalan, Vithiagaran; Tan, Timothy. H.P.; Chou, Chih-Fong; Shen, Shou; Khan, Sehaam; Lim, Seng Gee; Hong, Wanjin; Tan, Yee-Joo (Elsevier, 2006)[more][less]
Abstract: Severe acute respiratory syndrome coronavirus (SARS-CoV) 7a is an accessory protein with no known homologues. In this study, we report the interaction of a SARS-CoV 7a and small glutamine-rich tetratricopeptide repeat-containing protein (SGT). SARS-CoV 7a and human SGT interaction was identified using a two-hybrid system screen and confirmed with interaction screens in cell culture and cellular co-localization studies. The SGT domain of interaction was mapped by deletion mutant analysis and results indicated that tetratricopeptide repeat 2 (aa 125-158) was essential for interaction. We also showed that 7a interacted with SARS-CoV structural proteins M (membrane) and E (envelope), which have been shown to be essential for virus-like particle formation. Taken together, our results coupled with data from studies of the interaction between SGT and HIV-1 vpu indicated that SGT could be involved in the life-cycle, possibly assembly of SARS-CoV. URI: http://hdl.handle.net/10566/882 Files in this item: 0
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Abdul-Rasool, Sahar; Fielding, Burtram C. (Bentham Science, 2010)[more][less]
Abstract: Even though coronavirus infection of humans is not normally associated with severe diseases, the identification of the coronavirus responsible for the outbreak of severe acute respiratory syndrome showed that highly pathogenic coronaviruses can enter the human population. Shortly thereafter, in Holland in 2004, another novel human coronavirus (HCoV-NL63) was isolated from a seven-month old infant suffering from respiratory symptoms. This virus has subsequently been identified in various countries, indicating a worldwide distribution. HCoV-NL63 has been shown to infect mainly children and the immunocommpromised, who presented with either mild upper respiratory symptoms (cough, fever and rhinorrhoea) or more serious lower respiratory tract involvement such as bronchiolitis and croup, which was observed mainly in younger children. In fact, HCoV-NL63 is the aetiological agent for up to 10% of all respiratory diseases. This review summarizes recent findings of human coronavirus HCoV-NL63 infections, including isolation and identification, phylogeny and taxonomy, genome structure and transcriptional regulation, transmission and pathogenesis, and detection and diagnosis. Description: Clinical featuresPathogenesisDiagnosis URI: http://hdl.handle.net/10566/734 Files in this item: 1
Abdul-RasoolHumanCoronavirus2010.pdf (688.8Kb) -
Dutta, Sujit; Gupta, Garvita; Choi, Yook-Wah; Kotaka, Masayo; Fielding, Burtram C.; Song, Jianxing; Tan, Yee-Joo (Portland Press, 2012)[more][less]
Abstract: RNA helicases of the DEAD (Asp-Glu-Ala-Asp)-box family of proteins are involved in many aspects of RNA metabolism from transcription to RNA decay, but most of them have also been shown to be multifunctional. The DEAD-box helicase DDX5 of host cells has been shown to interact with the RNA-dependent RNA polymerase (NS5B) of HCV (hepatitis C virus). In the present study, we report the presence of two independent NS5Bbinding sites in DDX5, one located at the N-terminus and another at the C-terminus. The N-terminal fragment of DDX5, which consists of the first 305 amino acids and shall be referred as DDX5-N, was expressed and crystallized. The crystal structure shows that domain 1 (residues 79–303) of DDX5 contains the typical features found in the structures of other DEADbox helicases. DDX5-N also contains the highly variable NTR (N-terminal region) of unknown function and the crystal structure reveals structural elements in part of the NTR, namely residues 52–78. This region forms an extensive loop and an α-helix. From co-immunoprecipitation experiments, the NTR of DDX5-N was observed to auto-inhibit its interaction with NS5B. Interestingly, the α-helix in NTR is essential for this auto-inhibition and seems to mediate the interaction between the highly flexible 1–51 residues in NTR and the NS5B-binding site in DDX5-N. Furthermore, NMR investigations reveal that there is a direct interaction between DDX5 and NS5B in vitro. URI: http://hdl.handle.net/10566/864 Files in this item: 0
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Now showing items 12-17 of 17