Editing Transcription factor (section)

=== Availability of other cofactors/transcription factors ===

Most transcription factors do not work alone.  Many large TF families form complex homotypic or heterotypic interactions through dimerization.<ref>{{Cite journal |vauthors=Amoutzias GD, Robertson DL, Van de Peer Y, Oliver SG |date=May 2008 |title=Choose your partners: dimerization in eukaryotic transcription factors |journal=Trends in Biochemical Sciences |volume=33 |issue=5 |pages=220–9 |doi=10.1016/j.tibs.2008.02.002 |pmid=18406148}}</ref> For gene transcription to occur, a number of transcription factors must bind to DNA regulatory sequences.  This collection of transcription factors, in turn, recruit intermediary proteins such as [[transcription coregulator|cofactors]] that allow efficient recruitment of the [[Transcription preinitiation complex|preinitiation complex]] and [[RNA polymerase]].  Thus, for a single transcription factor to initiate transcription, all of these other proteins must also be present, and the transcription factor must be in a state where it can bind to them if necessary.
Cofactors are proteins that modulate the effects of transcription factors. Cofactors are interchangeable between specific gene promoters; the protein complex that occupies the promoter DNA and the amino acid sequence of the cofactor determine its spatial conformation. For example, certain steroid receptors can exchange cofactors with [[NF-κB]], which is a switch between inflammation and cellular differentiation; thereby steroids can affect the inflammatory response and function of certain tissues.<ref>{{Cite journal |vauthors=Copland JA, Sheffield-Moore M, Koldzic-Zivanovic N, Gentry S, Lamprou G, Tzortzatou-Stathopoulou F, Zoumpourlis V, Urban RJ, Vlahopoulos SA |date=June 2009 |title=Sex steroid receptors in skeletal differentiation and epithelial neoplasia: is tissue-specific intervention possible? |journal=BioEssays |volume=31 |issue=6 |pages=629–41 |doi=10.1002/bies.200800138 |pmid=19382224 |s2cid=205469320}}</ref>