Details

Autor(en) / Beteiligte

• Weikum, Emily R
• de Vera, Ian Mitchelle S
• Nwachukwu, Jerome C
• Hudson, William H
• Nettles, Kendall W
• Kojetin, Douglas J
• Ortlund, Eric A

Titel

Tethering not required: the glucocorticoid receptor binds directly to activator protein-1 recognition motifs to repress inflammatory genes

Ist Teil von

• Nucleic acids research, 2017-08, Vol.45 (14), p.8596-8608

Ort / Verlag

England

Erscheinungsjahr

2017

Quelle

MEDLINE

Beschreibungen/Notizen

• The glucocorticoid receptor (GR) is a ligand-regulated transcription factor that controls the expression of extensive gene networks, driving both up- and down-regulation. GR utilizes multiple DNA-binding-dependent and -independent mechanisms to achieve context-specific transcriptional outcomes. The DNA-binding-independent mechanism involves tethering of GR to the pro-inflammatory transcription factor activator protein-1 (AP-1) through protein-protein interactions. This mechanism has served as the predominant model of GR-mediated transrepression of inflammatory genes. However, ChIP-seq data have consistently shown GR to occupy AP-1 response elements (TREs), even in the absence of AP-1. Therefore, the current model is insufficient to explain GR action at these sites. Here, we show that GR regulates a subset of inflammatory genes in a DNA-binding-dependent manner. Using structural biology and biochemical approaches, we show that GR binds directly to TREs via sequence-specific contacts to a GR-binding sequence (GBS) half-site found embedded within the TRE motif. Furthermore, we show that GR-mediated transrepression observed at TRE sites to be DNA-binding-dependent. This represents a paradigm shift in the field, showing that GR uses multiple mechanisms to suppress inflammatory gene expression. This work further expands our understanding of this complex multifaceted transcription factor.