Molecular Analysis of Human T-cell Leukemia Virus Type 2 Accessory Protein p28

Molecular Analysis of Human T-cell Leukemia Virus Type 2 Accessory Protein p28

Bibliographic Details
Main Author: Yamamoto, Brenda Michiyo
Language:English
Published: The Ohio State University / OhioLINK 2009
Subjects:
Virology
HTLV
p28
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=osu1241708950
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-osu12417089502021-08-03T05:55:49Z Molecular Analysis of Human T-cell Leukemia Virus Type 2 Accessory Protein p28 Yamamoto, Brenda Michiyo Virology HTLV p28 The human T-cell leukemia virus type 1 (HTLV-1) and type 2 (HTLV-2) are two pathogenic retroviruses. Although both viruses share a common genome organization and amino acid homology in common viral proteins, the incidence of disease with infection is distinct. Infection with HTLV-1 may result in the development of adult T-cell leukemia/lymphoma (ATL), an aggressive neoplastic disease, or a variety of immune-mediated/inflammatory disorders such as HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), whereas HTLV-2 is less pathogenic. Our studies focused on the open reading frame II encoded p28 protein of HTLV-2, which has been shown to negatively regulate viral expression by the nuclear retention of the tax/rex mRNA. A similar post-transcriptional regulatory function has been observed with HTLV-1 ORF-II p30. However, p28 contrasts p30 in that there appears to be no significant transcriptional effects.In Chapter 2, we examined the functional significance of p28 in HTLV-2 infection, proliferation, and immortalization of primary T-cells in culture, and viral infection and survival in a rabbit model of HTLV infection. We generated a novel HTLV-2 p28 termination clone (HTLV2Deltap28) in which a stop codon had been introduced into the p28 sequence without altering the amino acid sequence of the overlapping regulatory proteins, Tax and Rex. In short-term proliferation and long-term immortalization coculture assays, HTLV2Deltap28 infected and immortalized primary human T-cells, similar to wtHTLV-2. However, HTLV2Deltap28 had a lower capacity to establish persistent infection in rabbits, indicating the in vivo importance of HTLV-2 p28. These results are consistent with the hypothesis that p28 repression of Tax and Rex-mediated viral gene expression allows infected cells to avoid immune recognition and elimination, or acts to enhance early viral spread by enhancing the survival of HTLV-2 infected cells.In Chapter 3, we generated and characterized various dual-promoter and single-promoter lentiviral expression vectors. Post-transduction, p28 protein was readily detected with the dual-promoter vectors in 293T cells but not in Jurkat T-cells. The differential p28 protein expression was found to be due to cell-type specific translation mechanisms. To circumvent this problem we utilized a single-promoter lentiviral vector that expresses p28 via the murine stem cell virus (MSCV)-promoter, which resulted in efficient p28 protein expression in both T-cell lines and primary human CD8+ T-lymphocytes. In Chapter 4, the capacity of p28 to modify cellular gene expression was examined. In transient transfection studies, low doses of p28 modulated CRE- and NFκB-driven reporter constructs in 293T cells, suggesting the ability of p28 in modulating cellular gene expression. Interestingly, transduction of Jurkat T-cells with the lentiviral p28 expression vector had no significant effect on cellular proliferation. Additionally, initial analysis of global cellular gene expression by microarray analysis suggests that p28 results in nominal alterations in cellular gene expression.Collectively, data presented in this thesis indicates that p28 is critical for the establishment and survival of HTLV-2, compatible with the conclusion that the regulation of HTLV gene expression is a tightly controlled and complex process. Ultimately, while minimal, the impact of p28 upon cellular genes likely contributes to HTLV-2 establishment of infection in vivo. 2009-06-26 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1241708950 http://rave.ohiolink.edu/etdc/view?acc_num=osu1241708950 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Virology
HTLV
p28
spellingShingle Virology
HTLV
p28
Yamamoto, Brenda Michiyo
Molecular Analysis of Human T-cell Leukemia Virus Type 2 Accessory Protein p28
author Yamamoto, Brenda Michiyo
author_facet Yamamoto, Brenda Michiyo
author_sort Yamamoto, Brenda Michiyo
title Molecular Analysis of Human T-cell Leukemia Virus Type 2 Accessory Protein p28
title_short Molecular Analysis of Human T-cell Leukemia Virus Type 2 Accessory Protein p28
title_full Molecular Analysis of Human T-cell Leukemia Virus Type 2 Accessory Protein p28
title_fullStr Molecular Analysis of Human T-cell Leukemia Virus Type 2 Accessory Protein p28
title_full_unstemmed Molecular Analysis of Human T-cell Leukemia Virus Type 2 Accessory Protein p28
title_sort molecular analysis of human t-cell leukemia virus type 2 accessory protein p28
publisher The Ohio State University / OhioLINK
publishDate 2009
url http://rave.ohiolink.edu/etdc/view?acc_num=osu1241708950
work_keys_str_mv AT yamamotobrendamichiyo molecularanalysisofhumantcellleukemiavirustype2accessoryproteinp28
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