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Haematologica 2020 Volume 105(7):1802-1812
Hematopoiesis
The dynamic emergence of GATA1 complexes identified in in vitro embryonic stem cell differentiation and in vivo mouse fetal liver
Xiao Yu,1,2 Andrea Martella,1,3 Petros Kolovos,1,4 Mary Stevens,1
Ralph Stadhouders,1,5 Frank G. Grosveld1 and Charlotte Andrieu-Soler1,6,7
1Department of Cell Biology, ErasmusMC, Rotterdam, the Netherlands; 2Current address: Department of Medical Microbiology, Amsterdam University Medical Center, Amsterdam, the Netherlands; 3AstraZeneca, R&D Innovative Medicines, Cambridge Science Park, Milton Road, Cambridge, UK; 4Biotech Research & Innovation Centre, University of
5
Copenhagen, Copenhagen, Denmark; Department of Pulmonary Medicine, Erasmus MC,
Rotterdam, the Netherlands; 6Institut de Génétique Moléculaire Montpellier, Université de Montpellier, CNRS, Montpellier, France and 7Université de Paris, Laboratoire d’excellence (LabEx) du globule rouge GR-Ex, Paris, France
ABSTRACT
GATA1 is an essential transcriptional regulator of myeloid hematopoietic differentiation towards red blood cells. During ery- throid differentiation, GATA1 forms different complexes with other transcription factors such as LDB1, TAL1, E2A and LMO2 (“the LDB1 com- plex”) or with FOG1. The functions of GATA1 complexes have been stud- ied extensively in definitive erythroid differentiation; however, the tempo- ral and spatial formation of these complexes during erythroid development is unknown. We applied proximity ligation assay (PLA) to detect, localize and quantify individual interactions during embryonic stem cell differenti- ation and in mouse fetal liver (FL) tissue. We show that GATA1/LDB1 inter- actions appear before the proerythroblast stage and increase in a subset of the CD71+/TER119– cells to activate the terminal erythroid differentiation program in 12.5 day FL. Using Ldb1 and Gata1 knockdown FL cells, we studied the functional contribution of the GATA1/LDB1 complex during differentiation. This shows that the active LDB1 complex appears quite late at the proerythroblast stage of differentiation and confirms the power of PLA in studying the dynamic interaction of proteins in cell differentiation at the single cell level. We provide dynamic insight into the temporal and spa- tial formation of the GATA1 and LDB1 transcription factor complexes dur- ing hematopoietic development and differentiation.
Introduction
The first hematopoietic cells appear in yolk sac blood islands on embryonic day 6.5 (E6.5) during mouse development. On E10.5 to E11, definitive hematopoietic stem cells (HSC) appear in the aorta-gonad-mesonephros (AGM) region within the embryo (and the vitelline and umbilical arteries). They migrate to the fetal liver (FL), mature from pre-HSC to HSC, and after moving, reside in the adult bone mar- row.1,2 One of the lineages originating from HSC generates erythroid cells.
GATA1 is one of the essential transcription factors for the erythroid (and megakaryocytic) program. Gata1 knockouts (KO) (Gata1-/-) die between E9.5 to E10 due to a block of differentiation at the proerythroblast stage, leading to the absence of mature red blood cells.3,4 GATA1 can form several complexes to regulate ery- throid gene expression.5 Two proteins of particular interest bind directly to GATA1. The first, FOG1 (Friend of GATA1), binds to the N-terminal zinc finger (ZnF) of GATA1 and recruits the chromatin remodeling complex NuRD/MeCP1 and/or the C-terminal binding protein (CTBP) corepressor-containing complex to regulate GATA1 target genes.6 The second is LMO2, which is part of a larger complex7-9 con- taining the LIM-domain-binding protein 1 (LDB1). LDB1 functions as a scaffold
Correspondence:
CHARLOTTE ANDRIEU-SOLER
charlotte.andrieu-soler@igmm.cnrs.fr
Received: January 7, 2019. Accepted: October 3, 2019. Pre-published: October 3, 2019.
doi:10.3324/haematol.2019.216010
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