GATA1 and GATA2 Sense/Antisense Transcriptional Switching in Early Hematopoietic Development

The GATA1 and GATA2 genes play essential roles in hematopoietic development. GATA1 is the master regulator of erythropoiesis and GATA2 is required for the expansion and survival of hematopoietic progenitor and stem cells, as well as the development of mast cells. A switch in GATA expression occurs during erythropoiesis, with silencing of the GATA2 gene and increased expression of GATA1. A GATA2 antisense transcript ( GATA2-AS1) has been associated with silencing of GATA2 expression. We have identified a novel GATA1 antisense promoter located in the first intron that opposes the GATA1 promoter and generates a spliced antisense transcript complementary to the SUV39H1 H3K9 methyltransferase gene. The competition between opposing sense and antisense promotersin the GATA1 and GATA2 genes may play a central role in the switching of GATA expression that occurs during hematopoiesis. To address this hypothesis, gene expression analysis of cells expressing sense versus antisense transcripts from the GATA1 or GATA2 genes was performed using 5'scRNAseq data from in vitro differentiated CD34 cells. Cells expressing only sense or only antisense GATA1 transcriptswere readily detected and comprised the majority (90%) of cells with GATA1 transcripts. Differential gene expression analysis of cells with GATA1 sense-only versus cells with GATA1 antisense-only showed association of sense transcription with erythrocyte genes, whereas antisense expression was associated with a mast cell phenotype and upregulation of GATA2 transcript levels. Conversely, GATA2 antisense expressing cells had increased GATA1 transcription and an erythrocyte phenotype, and GATA2 sense expressing cells demonstrated mast cell-specific gene expression. Single cell RNAseq analysis of HL60 cells induced to differentiate in vitro identified significant changes in GATA2 gene expression. Induction of granulocyte differentiation in HL60 cells treated with DMSO resulted in increased GATA2 antisense transcription, whereas PMA induction of monocyte differentiation was associated with increased GATA2 sense transcription. Taken together these results indicate a central role for sense/antisense promoter switching in hematopoiesis.