Background
HTLV-1 is a retrovirus responsible for adult T-cell leukemia (ATL) in 5% of infected people. ATL is characterised by a monoclonal proliferation of infected CD4+ T lymphocytes in which a high telomerase activity associated to a poor prognosis has been observed [1]. Furthermore, HBZ is the only viral protein clearly detectable in all ATL patient samples. This protein has been shown to up-regulate the transcription of the catalytic subunit of telomerase, hTERT. Therefore interaction of HBZ with AP-1 transcription factor JunD on the proximal promoter of hTERT is required to up-regulate the gene [2].
Menin, a tumor suppressor, is known as a repressor of both JunD transcriptional activity [3] and hTERT transcription [4]. These data led us to investigate the mechanisms underlying hTERT up-regulation by HBZ and JunD in the presence of Menin.