Our Technophile
Preethi J
Past Research Staff
Preethi J (2002-2006): Preethi Jayanth got hired in Rizvi Lab, when Prof. Rizvi moved to the UAE and worked in the laboratory from 2002 until 2006. She was instrumental in establishing the laboratory from the ground up. She later moved to Canada to pursue her PhD at Queen’s University and is currently working as the Animal Ethics Coordinator at the University of Guelph.
Publications
2012
Mustafa, F.; Amri, D. Al; Ali, F. Al; Sari, N. Al; Suwaidi, S. Al; Jayanth, P.; Philips, P. S.; Rizvi, T. A.
In: PLoS One, vol. 7, no. 10, pp. e47088, 2012, ISSN: 1932-6203.
@article{RN89,
title = {Sequences within both the 5' UTR and Gag are required for optimal in vivo packaging and propagation of mouse mammary tumor virus (MMTV) genomic RNA},
author = {F. Mustafa and D. Al Amri and F. Al Ali and N. Al Sari and S. Al Suwaidi and P. Jayanth and P. S. Philips and T. A. Rizvi},
doi = {10.1371/journal.pone.0047088},
issn = {1932-6203},
year = {2012},
date = {2012-01-01},
urldate = {2012-01-01},
journal = {PLoS One},
volume = {7},
number = {10},
pages = {e47088},
abstract = {BACKGROUND: This study mapped regions of genomic RNA (gRNA) important for packaging and propagation of mouse mammary tumor virus (MMTV). MMTV is a type B betaretrovirus which preassembles intracellularly, a phenomenon distinct from retroviruses that assemble the progeny virion at cell surface just before budding such as the type C human and feline immunodeficiency viruses (HIV and FIV). Studies of FIV and Mason-Pfizer monkey virus (MPMV), a type D betaretrovirus with similar intracellular virion assembly processes as MMTV, have shown that the 5' untranslated region (5' UTR) and 5' end of gag constitute important packaging determinants for gRNA. METHODOLOGY: Three series of MMTV transfer vectors containing incremental amounts of gag or 5' UTR sequences, or incremental amounts of 5' UTR in the presence of 400 nucleotides (nt) of gag were constructed to delineate the extent of 5' sequences that may be involved in MMTV gRNA packaging. Real time PCR measured the packaging efficiency of these vector RNAs into MMTV particles generated by co-transfection of MMTV Gag/Pol, vesicular stomatitis virus envelope glycoprotein (VSV-G Env), and individual transfer vectors into human 293T cells. Transfer vector RNA propagation was monitored by measuring transduction of target HeLaT4 cells following infection with viral particles containing a hygromycin resistance gene expression cassette on the packaged RNA. PRINCIPAL FINDINGS: MMTV requires the entire 5' UTR and a minimum of ~120 nucleotide (nt) at the 5' end of gag for not only efficient gRNA packaging but also propagation of MMTV-based transfer vector RNAs. Vector RNAs without the entire 5' UTR were defective for both efficient packaging and propagation into target cells. CONCLUSIONS/SIGNIFICANCE: These results reveal that the 5' end of MMTV genome is critical for both gRNA packaging and propagation, unlike the recently delineated FIV and MPMV packaging determinants that have been shown to be of bipartite nature.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
BACKGROUND: This study mapped regions of genomic RNA (gRNA) important for packaging and propagation of mouse mammary tumor virus (MMTV). MMTV is a type B betaretrovirus which preassembles intracellularly, a phenomenon distinct from retroviruses that assemble the progeny virion at cell surface just before budding such as the type C human and feline immunodeficiency viruses (HIV and FIV). Studies of FIV and Mason-Pfizer monkey virus (MPMV), a type D betaretrovirus with similar intracellular virion assembly processes as MMTV, have shown that the 5' untranslated region (5' UTR) and 5' end of gag constitute important packaging determinants for gRNA. METHODOLOGY: Three series of MMTV transfer vectors containing incremental amounts of gag or 5' UTR sequences, or incremental amounts of 5' UTR in the presence of 400 nucleotides (nt) of gag were constructed to delineate the extent of 5' sequences that may be involved in MMTV gRNA packaging. Real time PCR measured the packaging efficiency of these vector RNAs into MMTV particles generated by co-transfection of MMTV Gag/Pol, vesicular stomatitis virus envelope glycoprotein (VSV-G Env), and individual transfer vectors into human 293T cells. Transfer vector RNA propagation was monitored by measuring transduction of target HeLaT4 cells following infection with viral particles containing a hygromycin resistance gene expression cassette on the packaged RNA. PRINCIPAL FINDINGS: MMTV requires the entire 5' UTR and a minimum of ~120 nucleotide (nt) at the 5' end of gag for not only efficient gRNA packaging but also propagation of MMTV-based transfer vector RNAs. Vector RNAs without the entire 5' UTR were defective for both efficient packaging and propagation into target cells. CONCLUSIONS/SIGNIFICANCE: These results reveal that the 5' end of MMTV genome is critical for both gRNA packaging and propagation, unlike the recently delineated FIV and MPMV packaging determinants that have been shown to be of bipartite nature.
2009
Rizvi, T. A.; Ali, J.; Phillip, P. S.; Ghazawi, A.; Jayanth, P.; Mustafa, F.
In: Virology, vol. 385, no. 2, pp. 464-72, 2009, ISSN: 0042-6822.
@article{RN94,
title = {Role of a heterologous retroviral transport element in the development of genetic complementation assay for mouse mammary tumor virus (MMTV) replication},
author = {T. A. Rizvi and J. Ali and P. S. Phillip and A. Ghazawi and P. Jayanth and F. Mustafa},
doi = {10.1016/j.virol.2008.12.027},
issn = {0042-6822},
year = {2009},
date = {2009-01-01},
urldate = {2009-01-01},
journal = {Virology},
volume = {385},
number = {2},
pages = {464-72},
abstract = {The mouse mammary tumor virus (MMTV) is a type B retrovirus that is unique from other retroviruses in having multiple "tissue specific" and "hormone inducible" promoters. This unique feature has lead to the increasing interest in studying the biology of MMTV replication with the ultimate goal of developing MMTV based vectors for potentially targeted human gene therapy. In this report, we describe, for the first time, the establishment of an in vivo genetic complementation assay to study various aspects of MMTV replication. In the assay described here, the function of MMTV Rem/RmRE regulatory pathway has been successfully substituted by a heterologous retroviral constitutive transport element (CTE) from Mason Pfizer Monkey Virus (MPMV) for mature MMTV particle production. Our results revealed that in the absence of MPMV CTE or Rem/RmRE, RNA transcribed from MMTV Gag-Pol expression plasmids were efficiently transported to the cytoplasm. However, the presence of CTE was indispensable for Gag-Pol protein expression. In addition, we report the development of MMTV based vectors in which the packageable RNA was transcribed either from MMTV LTR or from a chimeric LTR, which could successfully be packaged and propagated by particles produced from MMTV Gag-Pol expression plasmids containing a heterologous transport element. The role of MPMV CTE in the transport of MMTV transfer vector RNA was not found to be significant. Development of such an assay should not only shed light on how MMTV regulates its gene expression, but also should provide additional molecular tools for delineating the packaging determinants for MMTV, which is imperative for the development of novel vectors for targeted and inducible gene therapy.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The mouse mammary tumor virus (MMTV) is a type B retrovirus that is unique from other retroviruses in having multiple "tissue specific" and "hormone inducible" promoters. This unique feature has lead to the increasing interest in studying the biology of MMTV replication with the ultimate goal of developing MMTV based vectors for potentially targeted human gene therapy. In this report, we describe, for the first time, the establishment of an in vivo genetic complementation assay to study various aspects of MMTV replication. In the assay described here, the function of MMTV Rem/RmRE regulatory pathway has been successfully substituted by a heterologous retroviral constitutive transport element (CTE) from Mason Pfizer Monkey Virus (MPMV) for mature MMTV particle production. Our results revealed that in the absence of MPMV CTE or Rem/RmRE, RNA transcribed from MMTV Gag-Pol expression plasmids were efficiently transported to the cytoplasm. However, the presence of CTE was indispensable for Gag-Pol protein expression. In addition, we report the development of MMTV based vectors in which the packageable RNA was transcribed either from MMTV LTR or from a chimeric LTR, which could successfully be packaged and propagated by particles produced from MMTV Gag-Pol expression plasmids containing a heterologous transport element. The role of MPMV CTE in the transport of MMTV transfer vector RNA was not found to be significant. Development of such an assay should not only shed light on how MMTV regulates its gene expression, but also should provide additional molecular tools for delineating the packaging determinants for MMTV, which is imperative for the development of novel vectors for targeted and inducible gene therapy.
2006
Ghazawi, A.; Mustafa, F.; Phillip, P. S.; Jayanth, P.; Ali, J.; Rizvi, T. A.
In: Microbes Infect, vol. 8, no. 3, pp. 767-78, 2006, ISSN: 1286-4579 (Print) 1286-4579.
@article{RN118,
title = {Both the 5' and 3' LTRs of FIV contain minor RNA encapsidation determinants compared to the two core packaging determinants within the 5' untranslated region and gag},
author = {A. Ghazawi and F. Mustafa and P. S. Phillip and P. Jayanth and J. Ali and T. A. Rizvi},
doi = {10.1016/j.micinf.2005.09.015},
issn = {1286-4579 (Print) 1286-4579},
year = {2006},
date = {2006-01-01},
urldate = {2006-01-01},
journal = {Microbes Infect},
volume = {8},
number = {3},
pages = {767-78},
abstract = {This study was undertaken to address the role of feline immunodeficiency virus (FIV) long terminal repeats (LTR) as potential packaging determinants. A number of studies in the recent past have clearly demonstrated that the core packaging determinants of FIV reside within at least two distinct regions at the 5' end of the viral genome, from R in the 5' LTR to approximately 150 bp within the 5' untranslated region (5' UTR) and within the first 100 bp of gag; however, there have been conflicting observations as to the role of the LTR regions in packaging and whether they contain the principal packaging determinants of FIV. Using a semi-quantitative RT-PCR approach on heterologous non-viral vector RNAs in an in vivo packaging assay, this study demonstrates that the principal packaging determinants of FIV reside within the first 150 bp of 5' UTR and 100 bp of gag (the two core regions) and not the viral 5' LTR. Furthermore, it shows that in addition to the 5' LTR, the 3' LTR also contains packaging determinants, but of a less significant nature compared to the core packaging determinants. This study defines the relative contribution of the various regions implicated in FIV genomic RNA packaging, and reveals that like other primate lentiviruses, the packaging determinants of FIV are multipartite and spread out, an observation that has implications for safer and more streamlined design of FIV-based gene transfer vectors.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This study was undertaken to address the role of feline immunodeficiency virus (FIV) long terminal repeats (LTR) as potential packaging determinants. A number of studies in the recent past have clearly demonstrated that the core packaging determinants of FIV reside within at least two distinct regions at the 5' end of the viral genome, from R in the 5' LTR to approximately 150 bp within the 5' untranslated region (5' UTR) and within the first 100 bp of gag; however, there have been conflicting observations as to the role of the LTR regions in packaging and whether they contain the principal packaging determinants of FIV. Using a semi-quantitative RT-PCR approach on heterologous non-viral vector RNAs in an in vivo packaging assay, this study demonstrates that the principal packaging determinants of FIV reside within the first 150 bp of 5' UTR and 100 bp of gag (the two core regions) and not the viral 5' LTR. Furthermore, it shows that in addition to the 5' LTR, the 3' LTR also contains packaging determinants, but of a less significant nature compared to the core packaging determinants. This study defines the relative contribution of the various regions implicated in FIV genomic RNA packaging, and reveals that like other primate lentiviruses, the packaging determinants of FIV are multipartite and spread out, an observation that has implications for safer and more streamlined design of FIV-based gene transfer vectors.
2005
Mustafa, F.; Ghazawi, A.; Jayanth, P.; Phillip, P. S.; Ali, J.; Rizvi, T. A.
In: J Virol, vol. 79, no. 21, pp. 13817-21, 2005, ISSN: 0022-538X (Print) 0022-538x.
@article{RN121,
title = {Sequences intervening between the core packaging determinants are dispensable for maintaining the packaging potential and propagation of feline immunodeficiency virus transfer vector RNAs},
author = {F. Mustafa and A. Ghazawi and P. Jayanth and P. S. Phillip and J. Ali and T. A. Rizvi},
doi = {10.1128/jvi.79.21.13817-13821.2005},
issn = {0022-538X (Print) 0022-538x},
year = {2005},
date = {2005-01-01},
urldate = {2005-01-01},
journal = {J Virol},
volume = {79},
number = {21},
pages = {13817-21},
abstract = {The packaging determinants of feline immunodeficiency virus (FIV) consist of two discontinuous core regions, extending from R to approximately 150 bp of the 5' untranslated region and the first approximately 100 bp of gag. However, the role of sequences intervening between the core regions in packaging has not been clear. A mutational analysis was conducted to determine whether the intervening sequences played a role in FIV RNA packaging, using an in vivo packaging assay complemented with semiquantitative reverse transcriptase PCR. Our analyses reveal that the intervening sequences are dispensable not only for vector RNA packaging but also for propagation, confirming the discontinuous nature of the FIV packaging signal.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The packaging determinants of feline immunodeficiency virus (FIV) consist of two discontinuous core regions, extending from R to approximately 150 bp of the 5' untranslated region and the first approximately 100 bp of gag. However, the role of sequences intervening between the core regions in packaging has not been clear. A mutational analysis was conducted to determine whether the intervening sequences played a role in FIV RNA packaging, using an in vivo packaging assay complemented with semiquantitative reverse transcriptase PCR. Our analyses reveal that the intervening sequences are dispensable not only for vector RNA packaging but also for propagation, confirming the discontinuous nature of the FIV packaging signal.
Mustafa, F.; Jayanth, P.; Phillip, P. S.; Ghazawi, A.; Schmidt, R. D.; Lew, K. A.; Rizvi, T. A.
Relative activity of the feline immunodeficiency virus promoter in feline and primate cell lines Journal Article
In: Microbes Infect, vol. 7, no. 2, pp. 233-9, 2005, ISSN: 1286-4579 (Print) 1286-4579.
@article{RN139,
title = {Relative activity of the feline immunodeficiency virus promoter in feline and primate cell lines},
author = {F. Mustafa and P. Jayanth and P. S. Phillip and A. Ghazawi and R. D. Schmidt and K. A. Lew and T. A. Rizvi},
doi = {10.1016/j.micinf.2004.10.015},
issn = {1286-4579 (Print) 1286-4579},
year = {2005},
date = {2005-01-01},
urldate = {2005-01-01},
journal = {Microbes Infect},
volume = {7},
number = {2},
pages = {233-9},
abstract = {The feline immunodeficiency virus (FIV) long terminal repeat (LTR), compared with some primate lentiviral LTRs, is quite a strong basal promoter. However, it seems to be highly species-specific in function and generally not very efficient in cells of non-feline origin. This study systematically explored the function of the FIV LTR in simian Cos cells compared with its activity in feline and human cells. Our studies, using biologically relevant two- and three-plasmid trans complementation assays followed by semi-quantitative reverse transcriptase PCR, show that the FIV LTR is functional in Cos cells. The results of the Cos experiment are different from previously reported literature and suggest that the strain specificity of the FIV LTR is an important determinant of whether the LTR will be functional in a particular cell type.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The feline immunodeficiency virus (FIV) long terminal repeat (LTR), compared with some primate lentiviral LTRs, is quite a strong basal promoter. However, it seems to be highly species-specific in function and generally not very efficient in cells of non-feline origin. This study systematically explored the function of the FIV LTR in simian Cos cells compared with its activity in feline and human cells. Our studies, using biologically relevant two- and three-plasmid trans complementation assays followed by semi-quantitative reverse transcriptase PCR, show that the FIV LTR is functional in Cos cells. The results of the Cos experiment are different from previously reported literature and suggest that the strain specificity of the FIV LTR is an important determinant of whether the LTR will be functional in a particular cell type.
2004
Mustafa, F.; Phillip, P. S.; Jayanth, P.; Ghazawi, A.; Lew, K. A.; Schmidt, R. D.; Rizvi, T. A.
Close proximity of the MPMV CTE to the polyadenylation sequences is important for efficient function in the subgenomic context Journal Article
In: Virus Res, vol. 105, no. 2, pp. 209-18, 2004, ISSN: 0168-1702 (Print) 0168-1702.
@article{RN143,
title = {Close proximity of the MPMV CTE to the polyadenylation sequences is important for efficient function in the subgenomic context},
author = {F. Mustafa and P. S. Phillip and P. Jayanth and A. Ghazawi and K. A. Lew and R. D. Schmidt and T. A. Rizvi},
doi = {10.1016/j.virusres.2004.06.014},
issn = {0168-1702 (Print) 0168-1702},
year = {2004},
date = {2004-01-01},
urldate = {2004-01-01},
journal = {Virus Res},
volume = {105},
number = {2},
pages = {209-18},
abstract = {The constitutive transport element (CTE) of Mason-Pfizer monkey virus (MPMV) is a short cis-acting sequence element critical for virus gene expression. Analogous to the Rev/Rev Responsive Element (RRE) of primate lentiviruses, CTE allows the nucleocytoplasmic transport of unspliced viral mRNAs. In fact, CTE can functionally replace Rev/RRE in the genomic context and has been used successfully in the expression of viral and cellular genes from expression vectors as well. However, unlike RRE, CTE accomplishes this by interacting with cellular factors, making CTE function independent of co-expressed trans factors. Thus, CTE has proven to be a valuable tool in the expression of heterologous genes. Our previous studies have shown that close proximity of CTE to the polyadenylation sequences is important for CTE function in the genomic context. However, it is controversial whether CTE needs to be located spatially close to the polyadenylation sequences in the subgenomic context. Since CTE is being frequently used in expression vectors, we investigated the position dependency of CTE in the heterologous, subgenomic background using both genetic and structural analyses. Our results reveal that similar to the genomic situation, close proximity of CTE to the polyadenylation sequences is important for its function in the heterologous subgenomic context.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The constitutive transport element (CTE) of Mason-Pfizer monkey virus (MPMV) is a short cis-acting sequence element critical for virus gene expression. Analogous to the Rev/Rev Responsive Element (RRE) of primate lentiviruses, CTE allows the nucleocytoplasmic transport of unspliced viral mRNAs. In fact, CTE can functionally replace Rev/RRE in the genomic context and has been used successfully in the expression of viral and cellular genes from expression vectors as well. However, unlike RRE, CTE accomplishes this by interacting with cellular factors, making CTE function independent of co-expressed trans factors. Thus, CTE has proven to be a valuable tool in the expression of heterologous genes. Our previous studies have shown that close proximity of CTE to the polyadenylation sequences is important for CTE function in the genomic context. However, it is controversial whether CTE needs to be located spatially close to the polyadenylation sequences in the subgenomic context. Since CTE is being frequently used in expression vectors, we investigated the position dependency of CTE in the heterologous, subgenomic background using both genetic and structural analyses. Our results reveal that similar to the genomic situation, close proximity of CTE to the polyadenylation sequences is important for its function in the heterologous subgenomic context.