Data from: TAF4, a subunit of transcription factor II D, directs promoter occupancy of nuclear receptor HNF4A during post-natal hepatocyte differentiation

The functions of the TAF subunits of mammalian TFIID in physiological
processes remain poorly characterised. Here we describe a novel function
of TAFs in directing genomic occupancy of a transcriptional activator.
Using liver-specific inactivation in mice, we show that the TAF4 subunit
of TFIID is required for post-natal hepatocyte maturation. TAF4 promotes
pre-initiation complex (PIC) formation at post-natal expressed liver
function genes and down-regulates a subset of embryonic expressed genes by
increased RNA polymerase II pausing. The TAF4-TAF12 heterodimer interacts
directly with HNF4A and in vivo TAF4 is necessary to maintain
HNF4A-directed embryonic gene expression at post-natal stages and promotes
HNF4A occupancy of functional cis-regulatory elements adjacent to the
transcription start sites of post-natal expressed genes. Stable HNF4A
occupancy of these regulatory elements requires TAF4-dependent PIC
formation highlighting that these are mutually dependent events. Local
promoter-proximal HNF4A-TFIID interactions therefore act as instructive
signals for post-natal hepatocyte differentiation.