Pluripotent stem cells reveal erythroid-specific activities of the GATA1 N-terminus
Marta Byrska-Bishop, … , Mitchell J. Weiss, Stella T. Chou
Marta Byrska-Bishop, … , Mitchell J. Weiss, Stella T. Chou
Published January 26, 2015
Citation Information: J Clin Invest. 2015;125(3):993-1005. https://doi.org/10.1172/JCI75714.
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Research Article Stem cells

Pluripotent stem cells reveal erythroid-specific activities of the GATA1 N-terminus

Abstract

Germline GATA1 mutations that result in the production of an amino-truncated protein termed GATA1s (where s indicates short) cause congenital hypoplastic anemia. In patients with trisomy 21, similar somatic GATA1s-producing mutations promote transient myeloproliferative disease and acute megakaryoblastic leukemia. Here, we demonstrate that induced pluripotent stem cells (iPSCs) from patients with GATA1-truncating mutations exhibit impaired erythroid potential, but enhanced megakaryopoiesis and myelopoiesis, recapitulating the major phenotypes of the associated diseases. Similarly, in developmentally arrested GATA1-deficient murine megakaryocyte-erythroid progenitors derived from murine embryonic stem cells (ESCs), expression of GATA1s promoted megakaryopoiesis, but not erythropoiesis. Transcriptome analysis revealed a selective deficiency in the ability of GATA1s to activate erythroid-specific genes within populations of hematopoietic progenitors. Although its DNA-binding domain was intact, chromatin immunoprecipitation studies showed that GATA1s binding at specific erythroid regulatory regions was impaired, while binding at many nonerythroid sites, including megakaryocytic and myeloid target genes, was normal. Together, these observations indicate that lineage-specific GATA1 cofactor associations are essential for normal chromatin occupancy and provide mechanistic insights into how GATA1s mutations cause human disease. More broadly, our studies underscore the value of ESCs and iPSCs to recapitulate and study disease phenotypes.

Authors

Marta Byrska-Bishop, Daniel VanDorn, Amy E. Campbell, Marisol Betensky, Philip R. Arca, Yu Yao, Paul Gadue, Fernando F. Costa, Richard L. Nemiroff, Gerd A. Blobel, Deborah L. French, Ross C. Hardison, Mitchell J. Weiss, Stella T. Chou

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Figure 4

Global transcriptome analysis demonstrates that GATA1s mutations downregulate erythroid and upregulate myelo-megakaryocytic genes.

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Global transcriptome analysis demonstrates that GATA1s mutations downreg...
(A) Mean expression values of 10,873 expressed genes in T21/GATA1s (n = 3 replicates) versus T21/WT GATA1 (n = 6 replicates) iPSC–derived CD43+CD41+CD235+ progenitors. 273 genes were differentially expressed between T21/GATA1s and T21/WT GATA1, with a fold change of mean expression of less than 2 (217 genes, blue) or 2-fold or greater (56 genes, green). (B) GSEA on 273 differentially expressed genes using erythroid, megakaryocytic, and myeloid expression profiles from Novershtern et al. (30). Top: enrichment of 154 genes that were upregulated in T21/GATA1s as compared with T21/WT GATA1 progenitors in myeloid versus erythroid signature genes and in megakaryocytic versus erythroid genes. Bottom: enrichment of 119 downregulated genes in erythroid versus myeloid genes and in erythroid versus megakaryocytic genes. NES, normalized enrichment score; P values shown are from modified Kolmogorov-Smirnov test as implemented in GSEA. (C) Heat maps showing expression levels of 2-fold or greater upregulated (top) and downregulated (bottom) genes in T21/GATA1s versus T21/WT GATA1 progenitors (left) as well as in lineage-committed cells (right) based on expression levels in erythroid (n = 7 replicates of CD34–CD71loGlyA+, 6 of CD34–CD71–GlyA+ cells), myeloid (n = 6 replicates of basophils, 5 of eosinophils, 4 of neutrophils), and megakaryocytic (n = 5 replicates of CFU-megakaryocytes, CD34+CD41+CD61+CD45–, 7 of mature megakaryocytes, CD34–CD41+CD61+CD45–) cells from Novershtern et al. (30). Color scheme is row normalized from blue to red corresponding to minimum to maximum expression values in a given row, respectively. ZC3H12C, COL24A1, MIR221, P2RY12, PARP9, and OCIAD2 were not represented on microarrays from Novershtern et al. (30).