Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.64898/2026.10.19.760167

SP1 tethers NR2F2 to drive atrial cardiomyocyte identity

Gergen, P. N.·Clark, A. P.·Saucerman, J. J.
View original source ↗Export metadata ↓

Abstract

Human heart development is guided by complex gene regulatory networks (GRNs), which are difficult to unravel and differ from that in animal models. In this study, we use a systematic approach to identify gene interactions driving human fetal atrial cardiomyocyte identity. We inferred GRNs for atrial and ventricular cardiomyocytes from human fetal single-cell RNA-seq and ATAC-seq data, predicting transcription factors that differentially regulate atrial vs. ventricular cardiomyocyte identity. Comparison of GRNs constrained by ATAC-seq vs. promoter annotations revealed that during human heart development, the canonical transcription factor for atrial specification, NR2F2, drives atrial genes not directly but by interacting with SP1. The predicted NR2F2-SP1 relationship at atrial gene promoters was supported with AlphaFold predictions of biophysical tethering and comparison with previous ChIP-seq data. These predictions were experimentally validated in human iPSC-derived atrial cardiomyocyte differentiation, which was suppressed by SP1 knockdown. Further, proximity ligation experiments validated the physical interaction of NR2F2 and SP1 in the nucleus, coincident with atrial identity. This study reveals SP1 as a transcription factor necessary for atrial cardiomyocyte identity in human development, helping to coordinate the effects of NR2F2. Furthermore, comparing GRNs based on current and potential epigenetic state offers a novel systematic approach to study interactions between transcription factors, which is key to understanding complex GRNs.

Explore related subjects

developmental biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Gergen, P. N., Clark, A. P., Saucerman, J. J.. 2026-10-20. SP1 tethers NR2F2 to drive atrial cardiomyocyte identity. https://doi.org/10.64898/2026.10.19.760167

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Epigenetic Remodeling Increases Plasticity of Bovine Fibroblasts Without Improving Embryo and Stem Cell Development

Epigenetic memory, reinforced by redundant heterochromatic networks, is a major barrier to somatic cell reprogramming. In cattle, single-agent chromatin-modifying treatments show inconsistent efficacy, likely due to compensatory crosstalk among repressive marks. Here, we evaluated a multi-target small-molecule cocktail, GUSTC, combining GSK343 (EZH2 inhibitor), UNC0638 (G9a/GLP inhibitor), Sodium Butyrate (HDAC inhibitor), Trichostatin A (HDAC inhibitor), and Chaetocin (SUV39H1 inhibitor) to simultaneously target facultative and constitutive heterochromatin in bovine fibroblasts. At optimized, non-cytotoxic concentrations, GUSTC treatment reduced H3K9me2, H3K9me3, H3K27me3, and HP1-alpha levels while increasing H3K9 acetylation by immunofluorescence. Using GUSTC-treated fibroblasts as donor cells for somatic cell nuclear transfer did not significantly change cleavage (83.6% vs. 92.2%; p = 0.15), blastocyst rate (28.4% vs. 39.0%; p = 0.20), bovine embryonic stem cell line derivation efficiency (26.3% vs. 33.3% of seeded blastocysts; p = 0.57), or the core pluripotency marker profile (OCT4, NANOG, SOX2) of the resulting lines. In a separate, serum-free, pluripotency-permissive culture system, GUSTC-treated cells adopted a colony-like morphology and showed increased POU5F1 and NANOG expression, along with increased DNMT1, EHMT2, HDAC1, HDAC2, and SUV39H1 transcripts. GUSTC thus reduces repressive heterochromatin marks in donor fibroblasts and is associated with a potentially more reprogramming-permissive state, without detectable improvement in preimplantation developmental competence. It provides a starting point for chemical reprogramming strategies in cattle.

developmental biology↗
bioRxiv2026

Anatomically matched spatial comparisons identify Trps1 as a regulator of knee interzone formation

How the interzone forms and gives rise to articular cartilage, ligaments, and synovium is incompletely understood. Using our previously generated spatial and single-cell transcriptomic atlas of the mouse hindlimb, we compared the knee interzone with neighboring tissues and with the ankle interzone at matched positions, and identified Trps1 as a knee interzone-enriched candidate. Pseudotime analysis placed Trps1-high cells in a transitional state between chondrogenic progenitors and matrix-producing chondrocytes, with higher chondrogenic and lower fibroblastic program scores. Targeted Trps1 knockdown in hindlimb explants disrupted joint formation, permitted Col2a1 expression within the interzone, and reduced adjacent cartilage formation. The associated chondrogenic program was conserved in the human embryonic knee, whereas TRPS1 expression in osteoarthritic cartilage was associated with a fibroblastic matrix program. These results support a role for Trps1 in knee interzone development and show that anatomically matched spatial comparison with explant perturbation can nominate and test joint regulators.

developmental biology↗
bioRxiv2026

CDC25B couples ribosome biogenesis to cell cycle kinetics to promote spinal cord neurogenesis

During neurogenesis, neural progenitors undergo a tightly regulated transition from proliferation to differentiation, which requires precise coordination between cell cycle progression and molecular reprogramming. Although the role of CDC25B is well established in promoting G2/M transition through CDK1 activation, we previously showed that it is both necessary and sufficient to trigger neural progenitor differentiation, via CDK-dependent and CDK-independent mechanisms. However, the molecular networks underlying this neurogenic activity remain poorly understood. Here, using a gain-of-function approach in the chicken spinal cord combined with bulk RNA sequencing, we show that CDC25B overexpression upregulates transcripts encoding ribosomal proteins and enhances ribosome biogenesis (RiBi) in neural progenitors. Consistent with these findings, during normal development, RiBi increases in neurogenic progenitor domains expressing CDC25B. Notably, the increase in RiBi is not associated with an increase in translation in neural progenitors. Instead, it is followed by an increase in mTORC1 activity in neuronal precursors and subsequently by a rise in the global translation rate in differentiating neurons. Moreover, increasing mTORC1 activity is sufficient to trigger a premature transition of neuronal precursors to the next step of differentiation. Altogether, our data support a model in which CDC25B coordinates cell cycle progression with RiBi in neurogenic progenitors, thereby initiating a program that culminates in translation in differentiating neurons.

developmental biology↗