The GATA1s isoform is normally down-regulated during terminal haematopoietic differentiation and over-expression leads to failure to repress MYB, CCND2 and SKI during erythroid differentiation of K562 cells

Abstract

BackgroundAlthough GATA1 is one of the most extensively studied haematopoietic transcription factors little is currently known about the physiological functions of its naturally occurring isoforms GATA1s and GATA1FL in humans—particularly whether the isoforms have distinct roles in different lineages and whether they have non-redundant roles in haematopoietic differentiation. As well as being of general interest to understanding of haematopoiesis, GATA1 isoform biology is important for children with Down syndrome associated acute megakaryoblastic leukaemia (DS-AMKL) where GATA1FL mutations are an essential driver for disease pathogenesis.MethodsHuman primary cells and cell lines were analyzed using GATA1 isoform specific PCR. K562 cells expressing GATA1s or GATA1FL transgenes were used to model the effects of the two isoforms on in vitro haematopoietic differentiation.ResultsWe found no evidence for lineage specific use of GATA1 isoforms; however GATA1s transcripts, but not GATA1FL transcripts, are down-regulated during in vitro induction of terminal megakaryocytic and erythroid differentiation in the cell line K562. In addition, transgenic K562-GATA1s and K562-GATA1FL cells have distinct gene expression profiles both in steady state and during terminal erythroid differentiation, with GATA1s expression characterised by lack of repression of MYB, CCND2 and SKI.ConclusionsThese findings support the theory that the GATA1s isoform plays a role in the maintenance of proliferative multipotent megakaryocyte-erythroid precursor cells and must be down-regulated prior to terminal differentiation. In addition our data suggest that SKI may be a potential therapeutic target for the treatment of children with DS-AMKL.

Regulation of MYB by distal enhancer elements in human myeloid leukemia

“…4I ), while GATA1 knockdown reduced MYB expression (Fig. 4J ), indicating GATA1 plays an important role in MYB expression, and corroborating a previous study that GATA1 overexpression leads to failure to repress MYB during erythroid differentiation of K562 cells 36 . Together, our data showed that TF binding at the −34k enhancer elements play a critical role in MYB expression in K562 cells.…”

GATA‐1 isoforms differently contribute to the production and compartmentation of reactive oxygen species in the myeloid leukemia cell line K562

“…The rationale for using optical techniques is to detect biochemical and morphological features that are concurrent with precancerous conditions because light scattering could be more sensitive to morphological changes than other currently used visualizing techniques (Bellisola & Sorio, 2012). In this study spectral differences at wavelengths of 560 and 412.5 nm were found in K562 cells overexpressing GATA-1 FL (GATA-1 FL cells) or GATA-1 S (GATA-1 S cells), respectively, two GATA-1 isoforms that play opposite roles in the differentiation and proliferation processes of different hematopoietic lineages (Chlon et al, 2015;Doré & Crispino, 2011;Halsey et al, 2012;Kaneko et al, 2012).…”

Exploring the Leukemogenic Potential of GATA-1S, the Shorter Isoform of GATA-1: Novel Insights into Mechanisms Hampering Respiratory Chain Complex II Activity and Limiting Oxidative Phosphorylation Efficiency

“…In this context, the GATA-1 factor plays a key role in regulating the expression of a large set of hematopoietic-related genes [32,61]. Therefore, not surprisingly, its dysregulated expression is emerging as a key factor in malignant hematopoiesis [32,62,63]. Two isoforms encoded from the same gene through alternative splicing or use of different translation start sites are known: the full-length GATA-1 isoform (GATA-1 FL ) and its shorter isoform (GATA-1 S ), lacking the N-terminal transactivation domain.…”