HLTF cooperates with GATA1 to activate transcriptional programs and chromatin remodeling during erythroid development

Abstract Erythropoiesis, the process by which hematopoietic stem cells differentiate into mature red blood cells, is tightly regulated by a complex network of transcriptional and epigenetic mechanisms. While helicase-like transcription factor (HLTF) is known for its roles in transcriptional regulation, chromatin remodeling, and genome stability, its function in erythroid development has remained unexplored. Here, we identify HLTF as a novel regulator of GATA1 and erythropoiesis. HLTF directly binds the GATA1 promoter, enhancing its transcription. In vitro and in vivo assays demonstrated that HLTF promotes erythroid proliferation, survival, and terminal differentiation. HLTF knockout impairs erythropoiesis, effects which are partially rescued by GATA1 overexpression. Multi-omics analyses (RNA-seq, ATAC-seq, and CUT&Tag) reveal that HLTF maintains chromatin accessibility and activates erythroid gene networks. HLTF interacts with GATA1, co-occupies erythroid regulatory regions, and facilitates GATA1 genomic binding. Notably, GATA1 also transcriptionally activates HLTF, forming a positive feedback loop. In erythroid disorders, HLTF is up-regulated in polycythemia vera (PV) and down-regulated in myelodysplastic syndromes (MDS). Knockout of HLTF in PV patient-derived cells suppressed erythroid hyperplasia, reduced chromatin accessibility, and impaired GATA1 binding. Together, these findings reveal HLTF as a transcriptional regulator of GATA1 and a pivotal modulator of erythropoiesis, providing new insights into erythroid lineage control and erythroid-related diseases.