Doctor of Philosophy, Yeshiva University (2014)
Master of Science, Yeshiva University (2010)
Master of Science, University Of Malaya (2006)
Bachelor of Science, University Of Malaya (2003)
Jan Carette, Postdoctoral Faculty Sponsor
BST2/Tetherin Inhibition of Alphavirus Exit.
; 7 (4): 2147-2167
Alphaviruses such as chikungunya virus (CHIKV) and Semliki Forest virus (SFV) are small enveloped RNA viruses that bud from the plasma membrane. Tetherin/BST2 is an interferon-induced host membrane protein that inhibits the release of many enveloped viruses via direct tethering of budded particles to the cell surface. Alphaviruses have highly organized structures and exclude host membrane proteins from the site of budding, suggesting that their release might be insensitive to tetherin inhibition. Here, we demonstrated that exogenously-expressed tetherin efficiently inhibited the release of SFV and CHIKV particles from host cells without affecting virus entry and infection. Alphavirus release was also inhibited by the endogenous levels of tetherin in HeLa cells. While rubella virus (RuV) and dengue virus (DENV) have structural similarities to alphaviruses, tetherin inhibited the release of RuV but not DENV. We found that two recently identified tetherin isoforms differing in length at the N-terminus exhibited distinct capabilities in restricting alphavirus release. SFV exit was efficiently inhibited by the long isoform but not the short isoform of tetherin, while both isoforms inhibited vesicular stomatitis virus exit. Thus, in spite of the organized structure of the virus particle, tetherin specifically blocks alphavirus release and shows an interesting isoform requirement.
View details for DOI 10.3390/v7042147
View details for PubMedID 25912717
Genome-Wide RNAi Screen Identifies Novel Host Proteins Required for Alphavirus Entry
2013; 9 (12)
The enveloped alphaviruses include important and emerging human pathogens such as Chikungunya virus and Eastern equine encephalitis virus. Alphaviruses enter cells by clathrin-mediated endocytosis, and exit by budding from the plasma membrane. While there has been considerable progress in defining the structure and function of the viral proteins, relatively little is known about the host factors involved in alphavirus infection. We used a genome-wide siRNA screen to identify host factors that promote or inhibit alphavirus infection in human cells. Fuzzy homologue (FUZ), a protein with reported roles in planar cell polarity and cilia biogenesis, was required for the clathrin-dependent internalization of both alphaviruses and the classical endocytic ligand transferrin. The tetraspanin membrane protein TSPAN9 was critical for the efficient fusion of low pH-triggered virus with the endosome membrane. FUZ and TSPAN9 were broadly required for infection by the alphaviruses Sindbis virus, Semliki Forest virus, and Chikungunya virus, but were not required by the structurally-related flavivirus Dengue virus. Our results highlight the unanticipated functions of FUZ and TSPAN9 in distinct steps of alphavirus entry and suggest novel host proteins that may serve as targets for antiviral therapy.
View details for DOI 10.1371/journal.ppat.1003835
View details for Web of Science ID 000330535400057
View details for PubMedID 24367265
Recombineering linear DNA that replicate stably in E-coli
2008; 59 (1): 63-71
The advent of recombineering technology in Escherichia coli has revolutionized the way recombinant DNA molecules are constructed. We present a novel application of recombineering to linearize DNA by capping their ends with individual telomeres derived from bacteriophage N15, which exists as a linear prophage in E. coli. The N15 telomerase occupancy site was recombined into circular DNA and resolved into individual telomeres by the phage N15 protelomerase enzyme. We demonstrate this technique by assembling linear BACs that replicate stably in their host strain E. coli DH10B. Correct linearization of the BACs was confirmed by restriction mapping using pulsed field gel electrophoresis. The linear BAC DNA can be easily purified using standard plasmid isolation methods and resist degradation from RecBCD nuclease in vitro and in vivo owing to the presence of telomeres. Transfection of a linear 100 kb BAC containing the human beta-globin gene cluster into HT1080 cells produced accurately spliced transcripts, demonstrating that the linear DNA will be useful for subsequent functional studies. This novel recombineering technique may be particularly useful for building large linear constructs for assembling artificial chromosomes with telomeres, and may provide a unique means to clone and study large linear viral genomes that contain hairpin ends.
View details for DOI 10.1016/j.plasmid.2007.09.002
View details for Web of Science ID 000253074300007
View details for PubMedID 17988739
STR data for the AmpFlSTR identifiler loci in three ethnic groups (Malay, Chinese, Indian) of the Malaysian population
FORENSIC SCIENCE INTERNATIONAL
2003; 138 (1-3): 134-?
Allele frequencies for the 15 STR loci in the AmpFlSTR Identifiler kit were determined and compared for the three main ethnic groups of the Malaysian population comprising 210 Malays, 219 Chinese and 209 Indians. Blood was placed on FTA paper and DNA was purified in-situ.
View details for DOI 10.1016/j.forsciint.2003.09.005
View details for Web of Science ID 000187029400021
View details for PubMedID 14642733