RT Journal Article
SR Electronic
T1 ETV4 and AP1 transcription factors form multivalent interactions with three sites on the MED25 activator-interacting domain
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 126458
DO 10.1101/126458
A1 Simon L. Currie
A1 Jedediah J. Doane
A1 Kathryn S. Evans
A1 Niraja Bhachech
A1 Bethany J. Madison
A1 Desmond K. W. Lau
A1 Lawrence P. McIntosh
A1 Jack J. Skalicky
A1 Kathleen A. Clark
A1 Barbara J. Graves
YR 2017
UL http://biorxiv.org/content/early/2017/04/11/126458.abstract
AB The recruitment of transcriptional cofactors by sequence-specific transcription factors challenges the basis of high affinity and selective interactions. Extending previous studies that the N-terminal activation domain (AD) of ETV5 interacts with Mediator subunit 25 (MED25), we establish that similar, aromatic-rich motifs located both in the AD and in the DNA-binding domain (DBD) of the related ETS factor ETV4 interact with MED25. These ETV4 regions bind MED25 independently, display distinct kinetics, and combine to contribute to a high-affinity interaction of full-length ETV4 with MED25. Within the ETS family, high-affinity interactions with MED25 are specific for the ETV1/4/5 subfamily as other ETS factors display weaker or no detectable binding. The AD binds to a single site on MED25 and the DBD interacts with three MED25 sites, allowing for simultaneous binding of both domains in full-length ETV4. MED25 also stimulates the in vitro DNA binding activity of ETV4 by relieving autoinhibition. ETV1/4/5 factors are often overexpressed in prostate cancer and genome-wide studies in a prostate cancer cell line indicate that ETV4 and MED25 occupy enhancers that are enriched for ETS-binding sequences and are both functionally important for the transcription of genes regulated by these enhancers. AP1-binding sequences were observed in MED25-occupied regions and JUN/FOS also contact MED25; FOS strongly binds to the same MED25 site as ETV4 AD and JUN interacts with the other two MED25 sites. In summary, we describe features of the multivalent ETV4- and AP1-MED25 interactions, thereby implicating these factors in the recruitment of MED25 to transcriptional control elements.ADactivation domainACIDactivator-interacting domainChIP-Seqchromatin immunoprecipitation followed by deep sequencingDBDDNA-binding domainETSE26-transformation specificMED25Mediator subunit 25HSQCheteronuclear single quantum coherenceAP1activator protein 1ARandrogen receptor