PXD005253

PXD005253 is an original dataset announced via ProteomeXchange.

Title	FOXA1 directs H3K4 monomethylation at enhancers via recruitment of the methyltransferase MLL3
Description	FOXA1 is a pioneer factor that is important in hormone dependent cancer cells to stabilise nuclear receptors, such as estrogen receptor (ER) to chromatin. FOXA1 binds to enhancers regions that are enriched in H3K4mono- and dimethylation (H3K4me1, H3K4me2) histone marks and evidence suggests that these marks are requisite events for FOXA1 to associate with enhancers to initate subsequent gene expression events. However, exogenous expression of FOXA1 has been shown to induce H3K4me1 and H3K4me2 signal at enhancer elements and the order of events and the functional importance of these events is not clear. We performed a FOXA1 Rapid Immunoprecipitation Mass Spectrometry of Endogenous Proteins (RIME) screen in ERα-positive MCF-7 breast cancer cells in order to identify FOXA1 interacting partners and we found histone-lysine N-methyltransferase (MLL3) as the top FOXA1 interacting protein. MLL3 is typically thought to induce H3K4me3 at promoter regions, but recent findings suggest it may contribute to H3K4me1 deposition, in line with our observation that MLL3 associates with an enhancer specific protein. We performed MLL3 ChIP-seq in breast cancer cells and unexpectedly found that MLL3 binds mostly at non-promoter regions enhancers, in contrast to the prevailing hypothesis. MLL3 was shown to occupy regions marked by FOXA1 occupancy and as expected, H3K4me1 and H3K4me2. MLL3 binding was dependent on FOXA1, indicating that FOXA1 recruits MLL3 to chromatin. Motif analysis and subsequent genomic mapping revealed a role for Grainy head like protein-2 (GRHL2) which was shown to co-occupy regions of the chromatin with MLL3. Regions occupied by all three factors, namely FOXA1, MLL3 and GRHL2, were most enriched in H3K4me1. MLL3 silencing decreased H3K4me1 at enhancer elements, but had no appreciable impact on H3K4me3 at enhancer elements. We identify a complex relationship between FOXA1, MLL3 and H3K4me1 at enhancers in breast cancer and propose a mechanism whereby the pioneer factor FOXA1 can interact with a chromatin modifier MLL3, recruiting it to chromatin to facilitate the deposition of H3K4me1 histone marks, subsequently demarcating active enhancer elements.
HostingRepository	PRIDE
AnnounceDate	2017-10-24
AnnouncementXML	Submission_2017-10-24_02:37:27.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Igor Chernukhin
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	iodoacetamide derivatized residue
Instrument	LTQ Orbitrap Velos

Revision	Datetime	Status	ChangeLog Entry
0	2016-11-02 02:59:40	ID requested
1	2016-12-12 14:42:56	announced
2	2016-12-14 02:31:24	announced	Updated publication reference for PubMed record(s): 27926873.
⏵ 3	2017-10-24 02:37:29	announced	Updated project metadata.

Jozwik KM, Chernukhin I, Serandour AA, Nagarajan S, Carroll JS, FOXA1 Directs H3K4 Monomethylation at Enhancers via Recruitment of the Methyltransferase MLL3. Cell Rep, 17(10):2715-2723(2016) [pubmed]

curator keyword: Biological, Biomedical

submitter keyword: FOXA1, MLL3, H3K4, Human, LCMSMS

Jason Carroll, PhD
contact affiliation	Head of Lab
contact email	Jason.Carroll@cruk.cam.ac.uk
lab head
Igor Chernukhin
contact affiliation	Cancer research UK Cambridge university
contact email	igor.chernukhin@cruk.cam.ac.uk
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD005253
     1. Label: PRIDE project
     2. Name: FOXA1 directs H3K4 monomethylation at enhancers via recruitment of the methyltransferase MLL3