DNA bending by the silencer protein NeP1 is modulated by TR and RXR.

AUTOR(ES)

Arnold, R

RESUMO

NeP1 binds to the F1 silencer element of the chicken lysozyme gene and, in the presence of TR, v-ERBA or RAR, synergistically represses transcriptional activity. This repression involves a silencing mechanism acting independently of the relative promoter position. Here we show that NeP1 alone can induce a significant directed bend on DNA. The chicken homologue of human NeP1, CTCF, shows identical binding and bending properties. In contrast, the isolated DNA binding domain of CTCF efficiently binds DNA, but fails to confer bending. Similarly, the TR-RXR hetero- or homodimer, binding adjacent to NeP1 at the F2 sequence, do not show significant DNA bending. The binding of the T3 ligand to TR changes neither the magnitude nor the direction of the NeP1 induced bend. However, when all factors are bound simultaneously as a quaternary complex, the TR-RXR heterodimer changes the location of the bend center, the flexure angle and the bending direction.

Documentos Relacionados

• DNA bending by thyroid hormone receptor: influence of half-site spacing and RXR.
• PMLRAR homodimers: distinct DNA binding properties and heteromeric interactions with RXR.
• The NF-kappa B transcription factor induces DNA bending which is modulated by its 65-kD subunit.
• Phytol metabolites are circulating dietary factors that activate the nuclear receptor RXR.
• Cyclicity of mosquito vitellogenic ecdysteroid-mediated signaling is modulated by alternative dimerization of the RXR homologue Ultraspiracle