Biology subjects

McNeill, H.

Publications and source records attributed to McNeill, H..

8 recordsLinked to original sources

bioRxiv2026

NEMP1 organizes the meiotic telomere LINC interface to control chromosome movement and telomere integrity

Nuclear Envelope Membrane Protein 1 (NEMP1) is highly expressed in oocytes and required for fertility, yet its meiotic function remains poorly understood. Here, we identify NEMP1 as a critical organizer of meiotic telomere-nuclear envelope coupling and chromosome dynamics. Loss of NEMP1 causes telomere aggregation, loss of shelterin protection, telomere shortening, persistent DNA damage, aberrant non-homologous end joining, and chromosome end-to-end fusion, ultimately leading to aneuploidy in mouse oocyte. NEMP1 is required during early fetal meiotic prophase I for telomere-nuclear envelope attachment, bouquet formation, homolog pairing, and synapsis. Live cell imaging revealed robust rapid prophase movements in wild-type meiocytes, which were nearly abolished by NEMP1 loss and restored by NEMP1-GFP re-expression. Mechanistically, NEMP1 associates with telomeric DNA and the SUN1-KASH5 LINC machinery, and SUN1-GFP restores chromosome movement in Nemp1-deficient meiocytes. Together, these findings establish NEMP1 as a nuclear-envelope organizer linking telomere protection, chromosome dynamics, and genome integrity during mammalian oogenesis.

developmental biology↗

bioRxiv2026

Dchs2, a novel Fat4 ligand, is required for photoreceptor organization and outer limiting membrane integrity in the mouse retina

Fat and Dachsous cadherins are large transmembrane proteins that regulate tissue growth and planar cell polarity across species. In mammals, Fat4 is known to bind Dchs1, but whether it also binds Dchs2 is unclear. Here we show that Dchs2 binds Fat4 in a trans-heterophilic manner at cell-cell contacts, mirroring the Fat4-Dchs1 interaction. In the developing mouse retina, Fat4 and Dchs1 expression peaks embryonically and declines after birth, whereas Dchs2 expression begins postnatally and persists into adulthood, with all three co-expressed from birth through the second postnatal week. While Fat4 and Dchs1 mutants show no defects in retinal lamination or cell-type composition, loss of Dchs2 increases number of cones, reduces Muller glia number, and results in disorganization of photoreceptor outer segments. Electron microscopy shows that Dchs2 mutant photoreceptors fail to form the regular nuclear columns seen in controls, with disrupted stacking and breaks in the outer limiting membrane. These findings identify Dchs2 as a novel Fat4 ligand and reveal a distinct, non-redundant requirement for Dchs2 in photoreceptor organization and outer limiting membrane integrity in the mature retina.

developmental biology↗

bioRxiv2025

Fat cadherin cleavage releases a transcriptionally active nuclear fragment to regulate target gene expression

The conserved atypical cadherin fat (ft) controls cellular processes such as growth, planar cell polarity, and mitochondrial function, in organisms ranging from fruit flies to mammals. Working at the apical-junctional plasma membrane the intracellular domain of the Ft protein, FtICD, binds to and regulates components of the Hippo and PCP pathways. Unexpectedly, we show that FtICD is present in the nucleus in cultured cells as well as in embryonic and larval tissues, and identify nuclear localization and nuclear export signals in FtICD required for this localization. We show that membrane-bound FtICD is cleaved and enters nuclei in vivo. Using endogenously tagged Ft as well as overexpressed FtICD we conducted ChIP-seq experiments and identified putative Ft targets including genes involved in signaling pathways, chromatin organization, pattern formation, and neural development. RNAseq demonstrates that some of these genes are differentially regulated in ft mutants. We observe strong correlations of Ft binding regions with peaks for other factors such as DREF and BEAF-32, as well as the Hpo pathway components Yorkie (Yki) and Scalloped (Sd), suggesting that Ft may act in conjunction with these factors to regulate gene expression. Supporting this hypothesis, we found that Ft can physically interact with both Yki and Sd in co-immunoprecipitation experiments in S2 cells. We propose that the modulation of Hippo pathway activity constitutes one of the nuclear functions of Ft, complementing its established function as an upstream regulator of Hippo signaling.

developmental biology↗

bioRxiv2022

Mouse NEMP1 is required for erythropoiesis, nuclear envelope openings and enucleation of erythroblasts

Nuclear Envelope Membrane Proteins (NEMP) are a conserved family of nuclear envelope proteins that reside within the inner nuclear membrane. Even though Nemp1 knockout (KO) mice are overtly normal, they display a pronounced splenomegaly. This phenotype and recent reports describing a requirement for nuclear envelope openings during erythroblasts terminal maturation led us to examine a potential role for Nemp1 in erythropoiesis. Here, we report that Nemp1 knockout (KO) mice show peripheral blood defects, anemia in neonates, ineffective erythropoiesis, splenomegaly and stress erythropoiesis. The erythroid lineage of Nemp1 KO mice is overrepresented until the pronounced apoptosis of polychromatophilic erythroblasts. We show that NEMP1 localizes to the nuclear envelope of erythroblasts and their progenitors. Mechanistically, we discovered that NEMP1 accumulates into aggregates that localize near or at the edge of nuclear envelope openings and Nemp1 deficiency leads to a marked decrease of both nuclear envelope openings and ensuing enucleation. Together, our results for the first time demonstrate that NEMP1 is essential for nuclear envelope openings and erythropoietic maturation in vivo and provide the first mouse model of defective erythropoiesis directly linked to the loss of an inner nuclear membrane protein.

cell biology↗

bioRxiv2022

An ancient role for the Hippo pathway in axis formation and morphogenesis

How did cells of early metazoan organisms first organize themselves to form a body axis? The canonical Wnt pathway has been shown to be sufficient for induction of axis in Cnidaria, a sister group to Bilateria, and is important in bilaterian axis formation. Here, we provide experimental evidence that in cnidarian Hydra the Hippo pathway regulates the formation of a new axis during budding upstream of the Wnt pathway. The target of Hippo pathway, the transcriptional co-activator YAP, inhibits the initiation of budding in Hydra, and is regulated by Hydra LATS. In addition, we show functions of Hippo pathway in regulation of actin organization and cell proliferation in Hydra. We hypothesize that Hippo pathway served as a link between continuous cell division, cell density and axis formation early in metazoan evolution.

developmental biology↗

bioRxiv2021

Epigenetic regulator genes direct lineage switching in MLL-AF4 leukaemia

The fusion gene MLL-AF4 defines a high-risk subtype of pro-B acute lymphoblastic leukaemia. However, relapse can be associated with a switch from acute lymphoblastic to acute myeloid leukaemia. Here we show that these myeloid relapses share oncogene fusion breakpoints with their matched lymphoid presentations and can originate in either early, multipotent progenitors or committed B-cell precursors. Lineage switching is linked to substantial changes in chromatin accessibility and rewiring of transcriptional programmes indicating that the execution and maintenance of lymphoid lineage differentiation is impaired. We show that this subversion is recurrently associated with the dysregulation of repressive chromatin modifiers, notably the nucleosome remodelling and deacetylation complex, NuRD. In addition to mutations, we show differential expression or alternative splicing of NuRD members and other genes is able to reprogram the B lymphoid into a myeloid gene regulatory network. Lineage switching in MLL-AF4 leukaemia is therefore driven and maintained by defunct epigenetic regulation. Statement of SignificanceWe demonstrate diverse cellular origins of lineage switched relapse within MLL-AF4 pro-B acute leukaemia. Irrespective of the developmental origin of relapse, dysregulation of NuRD and/or other epigenetic machinery underpins fundamental lineage reprogramming with profound implications for the increasing use of epitope directed therapies in this high-risk leukaemia.

cancer biology↗

bioRxiv2021

A human iPSC derived bone marrow milieu identifies a novel target against niche-conferred leukaemia proliferation and treatment resistance

Leukaemia cells re-program their microenvironment to provide proliferation support and protection from standard chemotherapy, molecularly targeted therapies, and immunotherapy. Although much is becoming known about molecules that drive niche-dependent treatment resistance; means of targeting these in the clinics has remained a key obstacle. To address this challenge, we have developed human induced pluripotent stem cell engineered niches ex vivo to reveal insights into druggable cancer-niche dependencies. We show that mesenchymal (iMSC) and vascular niche-like (iANG) cells support ex vivo proliferation of patient-derived leukaemia cells, impact dormancy and mediate therapy resistance. iMSC protected both non-cycling and cycling blasts against dexamethasone treatment while iANG protected only dormant blasts. Leukaemia proliferation and protection from dexamethasone induced-apoptosis was dependent on direct cell-cell contact and mediated by CDH2. To explore the therapeutic potential of disrupting this cell-cell interaction, we tested the CDH2 antagonist ADH-1 (previously in phase I / II for solid tumours) in a very aggressive patient-derived xenograft leukaemia mouse model. ADH-1 showed high in vivo efficacy. ADH-1/ dexamethasone combination therapy was superior to dexamethasone alone with no ADH1 conferred additional toxicity. These findings provide a proof-of-concept starting point to develop novel, potentially safer therapeutics that target niche-mediated cancer cell dependencies in haematological malignancies. SummaryCDH2 mediated niche-dependent cancer proliferation and treatment resistance is clinically targetable via ADH-1, a low toxic agent that could be potentially repurposed for future clinical trials in acute leukaemia.

cancer biology↗

bioRxiv2019

Ancestral role of Fat-like cadherins in planar cell polarity

Fat family cadherins are enormous proteins that regulate planar cell polarity (PCP) and cell adhesion in bilaterian animals. Their evolutionary origin can be traced back to prebilaterian species, but their ancestral function(s) are unknown. We identified Fat-like and Dachsous cadherins in Hydra, a member of the early-diverging metazoan phylum Cnidaria. Hydra has a simple body plan with only two epithelial layers and radial symmetry. We find that Hydra homologues of Fat-like (HyFat) and Dachsous (HyDs) co-localize at the apico-lateral membrane of ectodermal epithelial cells. Remarkably, HyFat is planar polarized perpendicular to the oral-aboral axis of the animal. Using knockdown approaches we found that HyFat is involved in the regulation of local cell alignment, but is dispensable for the global alignment of ectodermal myonemes along the oral-aboral axis. The intracellular domain (ICD) of HyFat is involved in the morphogenesis of ectodermal myonemes. Thus, Fat family cadherins have ancient, prebilaterian functions in cell adhesion, tissue organization and planar polarity.

developmental biology↗