Uncovering a Key Metabolic Role of the GATA1 N-Terminus in Red Blood Cell Development [CUT&Run]

Mutations in GATA1 that result in skipping of exon 2, which encodes the N-terminus, are associated with the myeloid leukemia of Down syndrome and Diamond-Blackfan anemia (DBA). To elucidate the molecular functions of the N-terminus, we employed single-cell RNA sequencing (scRNA-seq) of fetal liver cells derived from Gata1 mutant embryos that express the GATA1 short (GATA1s) isoform in place of full-length GATA1 (GATA1FL). scRNA-seq highlighted defects in erythropoiesis and revealed that the absence of the N-terminus resulted in elevated expression of genes involved in glycolysis, such as the rate-limiting pyruvate kinase PKM. To elucidate the regulation of the PKM gene, we performed precision nuclear run-on sequencing and cleavage under targets and release using nuclease on erythroid cells following acute deletion of GATA1 and determined that PKM is a direct target of GATA1. Mechanistically, we found that substitution of GATA1FL with GATA1s led to increased glycolysis in erythroid progenitor cells but did not affect oxidative phosphorylation. We further discovered that the expression of PKM is significantly elevated in DBA patients with RPS19 mutations, consistent with a role for GATA1 regulation of glycolysis in erythropoiesis. Together, these findings reveal that GATA1 controls not just heme metabolism, but also glycolysis. Overall design: Occupancy profiling was conducted on HUDEP1 clones expressing either the full-length GATA1 (GATA1FL) or the short isoform (GATA1s_1D5 and GATA1s_1KI9) under expansion or differentiation (on day 4 or 24-hour differentiation) conditions, utilizing the CUT&RUN method.