Transcriptional regulation of Satb1 in mouse trophoblast stem cells

Abstract

SATB homeobox proteins are important regulators of developmental gene expression. Among the stem cell lineages that emerge during early embryonic development, trophoblast stem (TS) cells exhibit robust SATB expression. Both SATB1 and SATB2 act to maintain the trophoblast stem-state. However, the molecular mechanisms that regulate TS-specific Satb expression are not yet known. We identified Satb1 variant 2 as the predominant transcript in trophoblasts. Histone marks, and RNA polymerase II occupancy in TS cells indicated an active state of the promoter. A novel cis-regulatory region with active histone marks was identified ∼21 kbp upstream of the variant 2 promoter. CRISPR/Cas9 mediated disruption of this sequence decreased Satb1 expression in TS cells and chromosome conformation capture analysis confirmed looping of this distant regulatory region into the proximal promoter. Scanning position weight matrices across the enhancer predicted two ELF5 binding sites in close proximity to SATB1 sites, which were confirmed by chromatin immunoprecipitation. Knockdown of ELF5 downregulated Satb1 expression in TS cells and overexpression of ELF5 increased the enhancer-reporter activity. Interestingly, ELF5 interacts with SATB1 in TS cells, and the enhancer activity was upregulated following SATB overexpression. Our findings indicate that trophoblast-specific Satb1 expression is regulated by long-range chromatin looping of an enhancer that interacts with ELF5 and SATB proteins.

Polycomb Repressive Complex 1.1 Component, BCOR, Promotes Syncytiotrophoblast Differentiation in Mice and Humans

“…Synb and Gcm1 were found to be downregulated at E9.5 (1.6-fold down, p adj =9.7 e-6 and 1.6-fold down, p adj =1.4 e-2 , respectively) in contrast to in vitro shRNA experiments showing these genes were upregulated(G. Zhu et al 2015). These decreases likely reflect a proportional reduction of cells in labyrinth layer within the dissected sample while stem cell markers, such as Satb1(Yu et al 2022) (1.6-fold up, p adj =1.2 e-6 ) and Tet1(Senner et al 2020) (1.9-fold up, p adj =1.9 e-6 ), are proportionally increased.…”

ELF5: A Molecular Clock for Breast Aging and Cancer Susceptibility

“…It is known that ELF5 serves as a gatekeeper, either strengthening the commitment to the trophoblast lineage or redirecting epiblast cells away from the pathway [34]. SATB1 was shown to interact with ELF5 through long-range chromatin looping in mouse trophoblast [39]. SATB1 recruits chromatin remodeling complexes to promote epigenetic modifications for gene regulation [40] and serves as a genome organizer, regulating numerous genes by tethering regulatory elements to SATB1 binding sites through the formation of chromatin loops [41,42].…”