Planutis, A. | Search bioRxiv

bioRxiv2021

Identification of a genomic DNA sequence that quantitatively modulates KLF1 expression in differentiating human hematopoietic cells

Expression of the {beta}-like globin genes is under strict developmental control, with both direct and indirect inputs responsible for this effect. One of the major players regulating their transition is KLF1/EKLF, where even a two-fold difference in its level alters the regulation of globin switching. We have reproduced this change in KLF1 expression in both cell lines and primary human cells, thus demonstrating that directed, quantitative control of KLF1 expression can be attained by genomic manipulation, and suggest a new way in which modulation of transcription factor levels may be used for clinical benefit.

molecular biology↗

bioRxiv2020

EKLF/KLF1 expression defines a unique macrophage subset during mouse erythropoiesis

Erythroblastic islands are a specialized niche that contain a central macrophage surrounded by erythroid cells at various stages of maturation. However, identifying the precise genetic and transcriptional control mechanisms in the island macrophage remains difficult due to macrophage heterogeneity. Using unbiased global sequencing and directed genetic approaches focused on early mammalian development, we find that fetal liver macrophage exhibit a unique expression signature that differentiates them from erythroid and adult macrophage cells. The importance of EKLF/KLF1 in this identity is shown by expression analyses in EKLF-/- and in EKLF-marked macrophage cells. Single cell sequence analysis simplifies heterogeneity and identifies clusters of genes important for EKLF-dependent macrophage function and novel cell surface biomarkers. Remarkably, this singular set of macrophage island cells appears transiently during embryogenesis. Together these studies provide a detailed perspective on the importance of EKLF in establishment of the dynamic gene expression network within erythroblastic islands in the developing embryo and provide the means for their efficient isolation.

developmental biology↗