In this project we have several aims:
Aim 1 : To integrate information obtained by functional biochemical studies on ectopically expressed non-structural HTLV-I proteins to infectivity and persistence of HTLV-I in relevant cellular models in vitro (dendritic cells and T-cells) Aim 2: To integrate information obtained by functional biochemical studies on ectopically expressed non-structural HTLV-I proteins to infectivity and persistence of HTLV-I in relevant animal models of HTLV-I infection. The viral genome encodes mRNAs for several non-structural proteins that affects cellular pathways and modulate viral replication in vitro. The p12 protein, encoded by orf I, localizes to the ER and Golgi and cellular membranes and different p12I cellular localization and functions are dictated by proteolytic cleavage. The removal of a non-canonical endoplasmic reticulum (ER) retention/retrieval signal within the amino terminus of p12I is necessary for trafficking to the Golgi apparatus and the generation of a completely cleaved 8 kDa protein. The 8 kDa protein in turn traffics to the cell surface, is recruited to the immunological synapse following T-cell receptor (TCR) ligation and down-regulates TCR proximal signaling. The uncleaved form of p12I resides in the ER and interacts with the b and gc chains of the interleukin-2 receptor (IL-2R), the heavy chain of the major histocompatibility complex (MHC) class I, as well as calreticulin and calnexin. Genetic analysis of ORF-I from ex vivo samples of HTLV-1-infected patients reveals predominant amino acid substitutions within ORF-I that inhibits proteolytic cleavage, suggesting that ER associated functions of p12I may be selected in vivo. We plan to use reverse genetic and use animal models to understand the contribution of variants of this viral gene to the maintenance of viral load in the host. The HTLV-I orf II encodes p30II, a nuclear/nucleolar protein that not only regulates viral expression by a post-transcriptional mechanism, but also affects the expression of genes involved in host responses such as TLR-4. In addition Orf II encodes p13, a small protein that we have recently demonstrate to decrease viral replication by targeting and degrading Tax, the viral trans activator. We have generated genetic mutant of HTLV-I that do not express p13 and/or p30 and found that the p30 affects dramatically the ability of HTLV-I to replicate in monocytoid-derived dendritic cells. The effect of p30 and p13 on in vitro infectivity is being tested in animal models. We also created HTLV-I mutants in the HBZ and found that the lack of HBZ result in an increased HTLV-I fusogenic ability.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Intramural Research (Z01)
Project #
1Z01BC005645-19
Application #
7732891
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
19
Fiscal Year
2008
Total Cost
$930,803
Indirect Cost
Name
National Cancer Institute Division of Basic Sciences
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Franchini, Genoveffa (2009) Choosing the right memory T cell for HIV. Nat Med 15:244-6
Fukumoto, Risaku; Andresen, Vibeke; Bialuk, Izabela et al. (2009) In vivo genetic mutations define predominant functions of the human T-cell leukemia/lymphoma virus p12I protein. Blood 113:3726-34
Younis, Ihab; Khair, Lyne; Dundr, Miroslav et al. (2004) Repression of human T-cell leukemia virus type 1 and type 2 replication by a viral mRNA-encoded posttranscriptional regulator. J Virol 78:11077-83
Nicot, Christophe; Dundr, Miroslav; Johnson, Julie M et al. (2004) HTLV-1-encoded p30II is a post-transcriptional negative regulator of viral replication. Nat Med 10:197-201
Franchini, Genoveffa; Nicot, Christophe; Johnson, Julie M (2003) Seizing of T cells by human T-cell leukemia/lymphoma virus type 1. Adv Cancer Res 89:69-132
D'Agostino, D M; Zotti, L; Ferro, T et al. (2000) The p13II protein of HTLV type 1: comparison with mitochondrial proteins coded by other human viruses. AIDS Res Hum Retroviruses 16:1765-70
Takemoto, S; Trovato, R; Cereseto, A et al. (2000) p53 stabilization and functional impairment in the absence of genetic mutation or the alteration of the p14(ARF)-MDM2 loop in ex vivo and cultured adult T-cell leukemia/lymphoma cells. Blood 95:3939-44
Nicot, C; Mahieux, R; Opavsky, R et al. (2000) HTLV-I Tax transrepresses the human c-Myb promoter independently of its interaction with CBP or p300. Oncogene 19:2155-64
Nicot, C; Opavsky, R; Mahieux, R et al. (2000) Tax oncoprotein trans-represses endogenous B-myb promoter activity in human T cells. AIDS Res Hum Retroviruses 16:1629-32
Trovato, R; Cereseto, A; Takemoto, S et al. (2000) Deletion of the p16INK4A gene in ex vivo acute adult T cell lymphoma/leukemia cells and methylation of the p16INK4A promoter in HTLV type I-infected T cell lines. AIDS Res Hum Retroviruses 16:709-13

Showing the most recent 10 out of 17 publications