Growth Factor Independence 1B-Mediated Transcriptional Repression and Lineage Allocation Require Lysine-Specific Demethylase 1-Dependent Recruitment of the BHC Complex

ABSTRACT

Growth factor independence 1B (GFI1B) coordinates assembly of transcriptional repressor complexes comprised of corepressors and histone-modifying enzymes to control gene expression programs governing lineage allocation in hematopoiesis. Enforced expression of GFI1B in K562 erythroleukemia cells favors erythroid over megakaryocytic differentiation, providing a platform to define molecular determinants of binary fate decisions triggered by GFI1B. We deployed proteome-wide proximity labeling to identify factors whose inclusion in GFI1B complexes depends upon GFI1B’s obligate effector, lysine-specific demethylase 1 (LSD1). We show that GFI1B preferentially recruits core and putative elements of the BRAF-histone deacetylase (HDAC) (BHC) chromatin-remodeling complex (LSD1, RCOR1, HMG20A, HMG20B, HDAC1, HDAC2, PHF21A, GSE1, ZMYM2, and ZNF217) in an LSD1-dependent manner to control acquisition of erythroid traits by K562 cells. Among these elements, depletion of both HMG20A and HMG20B or of GSE1 blocks GFI1B-mediated erythroid differentiation, phenocopying impaired differentiation brought on by LSD1 depletion or disruption of GFI1B-LSD1 binding. These findings demonstrate the central role of the GFI1B-LSD1 interaction as a determinant of BHC complex recruitment to enable cell fate decisions driven by GFI1B.

KEYWORDS:

• BHC complex
• Erythropoiesis
• GFI1B
• GSE1
• HMG20A
• HMG20B
• hematopoiesis
• LSD1
• SNAG domain
• transcriptional repression

SUPPLEMENTAL MATERIAL

Supplemental material for this article may be found at https://doi.org/10.1128/MCB.00020-19.

ACKNOWLEDGMENTS

We thank Katharine Ullman, Jason Gertz, Trudy Oliver, Charles Murtaugh, Rodney Stewart, and Mahesh Chandrasekharan for their helpful insights and suggestions during preparation of the manuscript. We acknowledge the following University of Utah Core facilities: DNA sequencing and cell line authentication were performed at the DNA Sequencing Core Facility, oligonucleotides were synthesized by the DNA/Peptide Facility of the Health Sciences Center (HSC), flow cytometry was performed by the Flow Cytometry Facility, and heme/porphyrin analysis was performed at the Heme & Iron Facility. Mass spectrometry was performed at the Taplin Mass Spectrometry Facility, Cell Biology Department, Harvard Medical School, with special thanks going to Ross Tomaino.

This work was supported by National Institutes of Health grants R01CA201235 (M.E.E.) and T32 DK007115 (D.M. and M.J.C.) and by grants from the American Cancer Society, Alex’s Lemonade Stand Foundation, and the Hyundai Hope on Wheels Foundation. We acknowledge support for C.C.M. from the Intermountain Healthcare and Primary Children's Hospital Foundations. The Flow Cytometry Facility is supported by the National Cancer Institute (grant 5P30CA042014-24), and the Heme & Iron Facility is supported in part by a grant from the NIH National Institute of Diabetes and Digestive and Kidney Diseases (U54DK110858).

The supporters had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

We declare no conflicts of interest associated with this article.