Volume 11 Supplement 1

16th International Conference on Human Retroviruses: HTLV and Related Viruses

Open Access

HTLV-1-mediated dysregulation of the Wnt pathways: roles of Tax and HBZ

  • Guangyong Ma1,
  • Jun-ichiro Yasunaga1Email author,
  • Jun Fan1,
  • Shin-ichi Yanagawa2 and
  • Masao Matsuoka1
Retrovirology201411(Suppl 1):P91

https://doi.org/10.1186/1742-4690-11-S1-P91

Published: 7 January 2014

Human T cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia (ATL). Dysregulations of cellular signaling pathways have been considered to be important strategies for HTLV-1 induced leukemogenesis. In this study, we found that a Wnt pathway-related protein, Dishevelled (Dvl)-associating protein with a high frequency of leucine residues (DAPLE), could be associated with Tax to activate the canonical Wnt signaling. However, in the downstream of the pathway, T-cell factor 1 (TCF1) and lymphoid enhancer-binding factor 1 (LEF1), which are two transcription factors mainly expressed in T-cells, could interact with Tax and suppress its transactivating ability. We further found virus production was greatly inhibited by TCF1/LEF1. Due to the high expression of TCF1/LEF1 in the thymus and their significant downregulation upon T-cell activation, we suspect TCF1/LEF1 may contribute to the HTLV-1 tropism on activated mature T-cells. On the other hand, HTLV-1 bZIP factor (HBZ) markedly suppressed canonical Wnt activation through targeting both TCF1 and LEF1. As a result, the canonical Wnt pathway was not activated in HTLV-1-infected cells, whereas the representative of noncanonical Wnt ligands, Wnt5a, which antagonizes canonical Wnt signaling, was overexpressed in HTLV-1 infected cells. Further experiments revealed HBZ could induce Wnt5a expression through activation of the TGF-β pathway. Importantly, knocking down of Wnt5a in HTLV-1-infected cells repressed cellular proliferation and migration. By suppressing the canonical and enhancing the noncanonical Wnt pathway, HBZ is likely able to generate a favorable environment for HTLV-1 infection and persistence.

Authors’ Affiliations

(1)
Laboratory of Virus Control, Institute for Virus Research, Kyoto University
(2)
Laboratory of Gene Analysis, Institute for Virus Research, Kyoto University

Copyright

© Ma et al; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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