GATA2 and PU.1 Collaborate To Activate the Expression of the Mouse Ms4a2 Gene, Encoding FcεRIβ, through Distinct Mechanisms

Abstract

GATA factors GATA1 and GATA2 and ETS factor PU.1 are known to function antagonistically during hematopoietic development. In mouse mast cells, however, these factors are coexpressed and activate the expression of the Ms4a2 gene encoding the β chain of the high-affinity IgE receptor (FcεRI). The present study showed that these factors cooperatively regulate Ms4a2 gene expression through distinct mechanisms. Although GATA2 and PU.1 contributed almost equally to Ms4a2 gene expression, gene ablation experiments revealed that simultaneous knockdown of both factors showed neither a synergistic nor an additive effect. A chromatin immunoprecipitation analysis showed that they shared DNA binding to the +10.4-kbp region downstream of the Ms4a2 gene with chromatin looping factor LDB1, whereas the proximal −60-bp region was exclusively bound by GATA2 in a mast cell-specific manner. Ablation of PU.1 significantly reduced the level of GATA2 binding to both the +10.4-kbp and −60-bp regions. Surprisingly, the deletion of the +10.4-kbp region by genome editing completely abolished the Ms4a2 gene expression as well as the cell surface expression of FcεRI. These results suggest that PU.1 and LDB1 play central roles in the formation of active chromatin structure whereas GATA2 directly activates the Ms4a2 promoter.

The Il6 -39 kb enhancer containing clustered GATA2- and PU.1-binding sites is essential for Il6 expression in murine mast cells

“…PU.1 recruits the chromatin looping factor LDB1 to the Spi1 locus, which confers an active chromatin configuration and facilitates autoregulation ( Schuetzmann et al., 2018 ). We also reported that PU.1 bound to the Ms4a2 gene locus recruits LDB1, which promotes GATA binding and robust Ms4a2 expression ( Ohmori et al., 2019 ). Therefore, a similar mechanism may operate in the Il6 locus.…”

“…Motif analysis of the 646 GATA2 peaks showed enrichment of GATA transcription factors followed by ETS domain transcription factors and runt domain transcription factors (RUNX) ( Figure 1 C). Because the ETS family transcription factor PU.1 functions with GATA2 in mast cells in several contexts ( Ohmori et al., 2019 ; Baba et al., 2012 ), we delineated the genome-wide binding profile of PU.1 using ChIP-seq in the same LPS-treated and untreated BRC6 cell samples. We identified 25,258 PU.1-binding peaks that commonly arose in the untreated and LPS-treated cells ( Figure 1 B).…”

“…Many studies have shown that GATA factors and PU.1 reciprocally inhibit their respective activities via multiple mechanisms ( Rekhtman et al., 1999 ; Zhang et al., 1999 , 2000 ; Nerlov et al., 2000 ; Arinobu et al., 2007 ; Burda et al., 2016 ). However, recent studies demonstrated that these factors cooperatively activate the expression of several genes in mast cells, including Il1rl1 , which encodes a transmembrane receptor for IL33, and Ms4a2 , which encodes the β-chain of the high-affinity IgE receptor (FcεRI) ( Baba et al., 2012 ; Ohmori et al., 2019 ). We recently demonstrated that the LPS-mediated induction of multiple peritoneal cytokines was under an intense regulatory influence of GATA2 ( Takai et al., 2021 ).…”

Transcription Factors in the Development and Pro-Allergic Function of Mast Cells

“…ChIP analysis revealed a shared region between GATA2 and PU.1 at a +10.4 kbp region downstream of Ms4a2 gene locus that encodes for β chain of the high-affinity IgE receptor (FcεRI), while a −60 bp region exclusively occupied by GATA2. The study also elucidated that ablation of PU.1 interfered with the binding of GATA2 to both the regions ( 129 ). Thus, the coregulation of these TFs plays a central role in the modulating the expression of mast cell genes by binding to common regulatory regions.…”

Gata2 heterozygous mutant mice exhibit reduced inflammatory responses and impaired bacterial clearance

“…Although GATA2 governs early hematopoietic development, mature hematopoietic and numerous other cell lineages in adult tissues sustain GATA2 expression as well ( Harigae et al., 1998 ; Li et al., 2015 ; Ohmori et al., 2012 ; Tsai and Orkin, 1997 ; Watanabe-Asaka et al., 2020 ; Wilson et al., 1990 ; Yu et al., 2014 ; Zon et al., 1993 ). For example, our group and others have demonstrated that GATA2 plays a key role in the maintenance and function of mast cells and participates in allergic inflammatory responses ( Li et al., 2017 , 2021 ; Ohmori et al., 2015 , 2019 ; Ohneda et al., 2019 ). We also showed that GATA2 exacerbated inflammatory kidney injury by promoting cytokine production from renal collecting duct cells ( Yu et al., 2017 ).…”