E box motifs as mediators of proviral latency of human retroviruses

Autor: Gazzolo Louis, Duc Dodon Madeleine, Calvignac Sébastien, Terme Jean-Michel, Jordan Albert
Jazyk: angličtina
Rok vydání: 2009
Předmět:
Zdroj: Retrovirology, Vol 6, Iss 1, p 81 (2009)
Druh dokumentu: article
ISSN: 1742-4690
DOI: 10.1186/1742-4690-6-81
Popis: Abstract The palindromic sequence motifs (CANNTG) known as E boxes are considered as binding sites for the basic helix-loop-helix (bHLH) class of DNA-binding proteins. Their presence has been reported in the long terminal repeats (LTR) of the HIV-1 and HTLV-1 proviruses. Their close proximity with the TATA region of both LTRs indicates that the bHLH proteins may act as important regulators of the function of proviral transcription. Indeed, observations on HIV-1 and recent results on HTLV-1 underline that these E boxes may be critically involved in the regulation of the proviral transcription of these human retroviruses. Indeed, of the two E boxes flanking the TATA sequences of the HIV-1 provirus, the 3' E box has been implicated in the transcriptional inhibition of viral gene expression. Such a role might also be played by the unique 5' E box present in the HTLV-1 LTR. In both cases, the expression of tissue-specfic bHLH proteins, like TAL1 might counteract the inhibitory effect exerted by E box proteins, thereby increasing proviral transcription. Finally, a phylogenetic study encompassing several subtypes of these two human retroviruses underlines that these E box motifs have recently appeared in the proviral LTRs and may be considered as potential mediators in the establishment of proviral latency.
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