The temporal and spatial emergence of GATA1 complexes in developing mouse embryos. Mus musculus musculus

GATA1 is an essential transcriptional regulator of myeloid hematopoietic differentiation towards red blood cells. During erythroid differentiation GATA1 forms different complexes with other transcription factors such as LDB1, TAL1, E2A and LMO2 (called the LDB1 complex) or with FOG1. The functions of the GATA1 complexes have been studied extensively in definitive erythroid differentiation; however, the temporal and spatial formation of these complexes during erythroid development is still unknown. We applied proximity ligation (PLA) to detect, localize and quantify individual interactions during ES cell differentiation and in mouse fetal liver tissue. We show that the GATA1/LDB1 interaction appears before the proerythroblast stage and increases in a subset of the CD71+/TER119- cell population to activate the terminal erythroid differentiation program in embryonic day 12.5 fetal liver. Using Ldb1 and Gata1 knockdown fetal liver cells, we studied the functional contribution of the LDB1/GATA1 complex during differentiation. This shows that the active LDB1 complex appears quite late at the proerythroblast stage of erythroid differentiation and confirms the power of PLA in studying the dynamic interaction of proteins in cell differentiation at the single cell level. This work offers dynamic insight in the temporal and spatial formation of the functional GATA1 and LDB1 transcription factor complexes during hematopoietic development and differentiation.