The multiprotein complex TFIID, comprising the TATA binding protein (TBP) and 13 TBP-associated factors (TAFs), is an essential component of the RNA polymerase II (Pol II) preinitiation complex (PIC). Cryo-electron microscopy studies suggested a critical role of the TAF11-TAF13 heterodimer in TBP promoter deposition upstream of the transcription start site. To investigate this hypothesis, we inactivated the gene encoding Taf13 in mice and embryonic stem cells (ESCs). Taf13-null embryos implant and survive until E6.5, but fail to undergo gastrulation, while Taf13-null ESCs are viable, but fail to form embryoid bodies and differentiate. Taf13 loss had little effect on TFIID integrity and led to only a mild reduction of TBP promoter recruitment, but led to altered PIC formation and globally reduced Pol II recruitment. Thus, the Taf11-Taf13 heterodimer is not essential for TBP/TFIID recruitment, revealing plasticity in the pathways of PIC formation.
© 2025 The Authors.

Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) is an essential tool for detecting cell death in tissues, but its compatibility with spatial proteomic methods is unknown. We evaluated variations of the TUNEL protocol for compatibility with multiple iterative labeling by antibody neodeposition (MILAN) in acetaminophen-induced hepatocyte necrosis and dexamethasone-induced adrenocortical apoptosis. Using a commercial Click-iT-based assay as a standard, TUNEL signal could be reliably produced independent of the antigen retrieval method, with tissue-specific minor differences in signal to noise. In contrast, proteinase K treatment consistently reduced or even abrogated protein antigenicity, while pressure cooker treatment enhanced protein antigenicity for the targets tested. Antibody-based TUNEL with pressure cooker retrieval could be flexibly integrated into a MILAN staining series, and first-round TUNEL was also compatible with a second spatial proteomic method, cyclic immunofluorescence (CycIF). We anticipate that this harmonization of TUNEL with spatial proteomics will enhance the spatial contextualization of cell death in complex tissues.
Copyright © 2025 The Authors. Published by Elsevier Inc. All rights reserved.

The steroid hormone aldosterone, produced by the zona glomerulosa (zG) of the adrenal gland, is a master regulator of plasma electrolytes and blood pressure. While aldosterone control by the renin-angiotensin system is well understood, other key regulatory factors have remained elusive. Here, we replicated a prior association between a non-coding variant in WNT2B and an increased risk of primary aldosteronism, a prevalent and debilitating disease caused by excessive aldosterone production. We further show that in both mice and humans, WNT2B is expressed in the mesenchymal capsule surrounding the adrenal cortex, in close proximity to the zG. Global loss of Wnt2b in the mouse results in a dysmorphic and hypocellular zG, with impaired aldosterone production. Similarly, humans harboring WNT2B loss-of-function mutations develop a novel form of Familial Hyperreninemic Hypoaldosteronism, designated here as Type 4. Additionally, we demonstrate that WNT2B signals by activating the non-canonical Wnt/planar cell polarity pathway. Our findings identify WNT2B as a key regulator of zG function and aldosterone production with important clinical implications. Highlights WNT2B variant is associated with increased risk for primary aldosteronism Wnt2b knock-out mice show defects in adrenal morphology Wnt2b knock-out mice have hyperreninemic hypoaldosteronism WNT2B activates non-canonical Wnt/planar cell polarity signaling WNT2B deficiency causes a new form of familial hyperreninemic hypoaldosteronism

Genetic defects affecting steroid biosynthesis cause cortisol deficiency and differences of sex development; among these defects are recessive mutations in the steroidogenic enzymes CYP11A1 and CYP11B, whose function is supported by reducing equivalents donated by ferredoxin reductase (FDXR) and ferredoxin. So far, mutations in the mitochondrial flavoprotein FDXR have been associated with a progressive neuropathic mitochondriopathy named FDXR-related mitochondriopathy (FRM), but cortisol insufficiency has not been documented. However, patients with FRM often experience worsening or demise following stress associated with infections. We investigated 2 female patients with FRM carrying the potentially novel homozygous FDXR mutation p.G437R with ambiguous genitalia at birth and sudden death in the first year of life; they presented with cortisol deficiency and androgen excess compatible with 11-hydroxylase deficiency. In addition, steroidogenic FDXR-variant cell lines reprogrammed from 3 patients with FRM fibroblasts displayed deficient mineralocorticoid and glucocorticoid production. Finally, Fdxr-mutant mice allelic to the severe p.R386W human variant showed reduced progesterone and corticosterone production. Therefore, our comprehensive studies show that human FDXR variants may cause compensated but possibly life-threatening adrenocortical insufficiency in stress by affecting adrenal glucocorticoid and mineralocorticoid synthesis through direct enzyme inhibition, most likely in combination with disturbed mitochondrial redox balance.

Cholesterol is the precursor of all steroids, but how cholesterol flux is controlled in steroidogenic tissues is poorly understood. The cholesterol exporter ABCG1 is an essential component of the reverse cholesterol pathway and its global inactivation results in neutral lipid redistribution to tissue macrophages. The function of ABCG1 in steroidogenic tissues, however, has not been explored. To model this, we inactivated Abcg1 in the mouse adrenal cortex, which led to an adrenal-specific increase in transcripts involved in cholesterol uptake and de novo synthesis. Abcg1 inactivation did not affect adrenal cholesterol content, zonation, or serum lipid profile. Instead, we observed a moderate increase in corticosterone production that was not recapitulated by the inactivation of the functionally similar cholesterol exporter Abca1. Altogether, our data imply that Abcg1 controls cholesterol uptake and biosynthesis and regulates glucocorticoid production in the adrenal cortex, introducing the possibility that ABCG1 variants may account for physiological or subclinical variation in stress response.
© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society.