Biology subjects

Greenberg, M. E.

Publications and source records attributed to Greenberg, M. E..

At least 19 recordsLinked to original sources

bioRxiv2026

Predicting cell-state-specific gene regulation from DNA across species

DNA encodes the cell's phenotype, but the same DNA sequence is interpreted differently in every cell type, developmental stage, and activity state. Existing deep-learning models solve only half of this puzzle: sequence-to-function models read DNA but treat cell state as a fixed label, while single-cell foundation models represent cell state but not sequence. We developed Bolero, a sequence-to-function model whose parameters condition on atlas-scale cell-state embeddings and additional biological variables to predict cell-state-specific chromatin accessibility and transcript abundance from DNA. Trained on 10.7 million cells from 33 datasets across six mammals, Bolero matched or exceeded specialised models and resolved regulatory differences between closely related cell states, including cortical regional and developmental gradients. Extrapolating cell-state embeddings extended Bolero's predictions to cell states that are absent from training. Cell-state conditioning facilitated tracing of the effects of non-coding variants to the cell types in which they act. Using an AP-1 activity score as a further continuous conditioning axis, Bolero predicted activity-regulated chromatin changes without requiring actual stimulation data. Across human cell types, we reconstructed the cooperative grammar of motif identity and spacing underlying predicted AP-1 responses. Bolero further predicted cell-type-specific chromatin accessibility and AP-1 responses in species excluded from training, extending comparative genomics from sequence conservation to predicted functional conservation. Across 84 mammals, we found that predicted AP-1 responses were less conserved than chromatin accessibility at cis-regulatory elements, driven by the human-specific sequence variants on AP-1 and cooperating motifs. By combining reference genomes with reference cell atlases, Bolero allowed genome sequences, either native or mutated, to be queried across cell states, perturbations, and different species for their chromatin and expression signatures.

genomics↗

bioRxiv2026

The functional diversification of somatosensory neuron repertoires across Mammalia

The striking diversity of mammalian body forms and surfaces, lifestyles, and habitats prompts the question of how each species' somatosensory neuron repertoire accommodates such diversity. The visual and olfactory systems diversify by gaining and losing sensor/receptor genes and corresponding sensory cell types. Using multiomic single-cell analysis of dorsal root ganglia neurons from thirteen different mammalian species and cross-species functional studies enabled by cell-type-specific enhancer viruses, we show that mammals instead assemble species-specific, functionally distinct somatosensory neuron repertoires from a conserved set of neuron types (orthotypes). Repertoire diversification takes multiple forms: orthotype abundance scales with variable bodily traits like hair follicle density, facilitating relevant behaviors; sensor/receptor expression is shuffled across species, such that orthotypes can detect different stimuli in different species; and orthotypes split into functionally distinct, species-specific subtypes (paratypes). Thus, unlike other sensory systems, the mammalian somatosensory system diversifies through multifarious changes to conserved orthotypes, enabling adaptation to diverse habitats, lifestyles, and body forms.

neuroscience↗

bioRxiv2026

The BAF complex works with FOS to regulate human neuronal activity-dependent ASD-associated gene programs

The BAF chromatin remodeling complex is critical to normal brain development, and rare variants within genes encoding BAF subunits are a common genetic cause of neurodevelopmental disorders, including autism spectrum disorder (ASD). Yet the factors that direct BAF binding across the neuronal genome, the human neuronal gene programs that are regulated by BAF, and the mechanisms whereby BAF subunit perturbation leads to ASD are not known. We find that BAF binds with the activity-dependent transcription factor FOS to distal regulatory regions that, in response to neuronal activity, undergo chromatin opening and show evidence of enhancer activation. Knock-out of ARID1A, a BAF subunit implicated in ASD, leads to decreased chromatin accessibility at FOS/BAF binding sites concomitant with decreased expression of nearby activity-regulated ASD-associated genes. Additionally, we find that the FOS binding motif in FOS/BAF-bound regions is highly constrained in the human population, and that rare variants in this motif in ASD-affected individuals disrupt stimulus-dependent enhancer activation. This suggests that genetic variation in FOS/BAF-bound regions contributes to ASD pathogenesis, due to an inability to recruit FOS and BAF to enhancers to promote gene expression. Together, our findings highlight a role for BAF in mediating neuronal transcriptional programs downstream of FOS and reveal a mechanism by which non-coding variants may impact BAF function and contribute to risk for ASD.

neuroscience↗

bioRxiv2025

ZMYND11 Restrains KMT2A to Enable a Neuronal Developmental Program

Mutations in the chromatin reader and tumor suppressor ZMYND11 are the cause of ZMYND11-related syndromic intellectual disability (ZRSID), a disorder characterized by symptoms such as language and motor delay, behavioral disruptions, and seizures. We find that neuronal deletion of ZMYND11 in mice causes aberrant upregulation of non-neuronal gene programs, leading to reduced dendritic branching and spine density, as well as hyperactivity and abnormal motor behavior. We investigated the mechanism by which ZMYND11 regulates gene expression and discovered that ZMYND11 interacts with and inhibits the histone methyltransferase KMT2A (MLL1), a transcriptional co-activator which contributes to oncogenic and developmental gene programs. We find that a ZRSID-associated ZMYND11 point mutation abrogates ZMYND11 interaction with KMT2A, suggesting that this interaction is critical for the function of ZMYND11 in regulating brain development. Using a degron-tagged ZMYND11 mouse model to enable the rapid degradation of ZMYND11 in primary cortical neurons, we show that gene expression changes induced by ZMYND11 loss are attenuated by treatment with the KMT2A inhibitor revumenib, a drug which has recently been approved for the treatment of KMT2A-rearranged leukemia. Our findings shed light on the convergence of chromatin mechanisms regulating neuronal gene expression and raise the possibility that modulation of KMT2A activity may be a useful therapeutic avenue for ZRSID.

neuroscience↗

bioRxiv2025

HuD controls widespread RNA stability to drive neuronal activity-dependent responses

Neuronal activity shapes brain development and refines synaptic connectivity in part through dynamic changes in gene expression. While activity-regulated transcriptional programs have been extensively characterized, the holistic effects of neuronal activity on the full RNA life cycle remain relatively unexplored. Here, we show that neuronal activity influences multiple stages of RNA metabolism in vitro and in vivo. Among these, RNA stability emerges as a previously underappreciated regulator of gene expression, exerting a stronger influence than transcription on total RNA levels for [~]15% of activity-dependent genes. We go on to profile 3'UTR mRNA motifs that are sufficient to modulate activity-dependent mRNA stability and employ machine learning to identify the neuronal-specific RNA-binding protein HuD as a key regulator of activity-dependent mRNA stabilization. We demonstrate that HuD shapes activity-dependent mRNA abundance of hundreds of transcripts in both soma and distal neuronal processes and that neuronal activity drives the reorganization of HuD-interacting proteins, thereby stabilizing HuD-bound mRNAs and directing them into translationally active granules. Finally, we find that many variants associated with autism spectrum disorder (ASD) and other neurodevelopmental disorders disrupt or promote aberrant activity-dependent changes in mRNA stability. These findings reveal mRNA stability as a widespread mechanism of stimulus-responsive gene regulation in neurons with direct implications for the understanding of neurodevelopmental disorders.

neuroscience↗

bioRxiv2025

FOS binding sites are a hub for the evolution of activity-dependent gene regulatory programs in human neurons

After birth, sensory inputs to neurons trigger the induction of activity-dependent genes (ADGs) that mediate many aspects of neuronal maturation and plasticity. To identify human-specific ADGs, we characterized these genes in human-chimpanzee tetraploid neurons. We identified 235 ADGs that are differentially expressed between human and chimpanzee neurons and found that their nearby regulatory sites are species-biased in their binding of the transcription factor FOS. An assessment of these sites revealed that many are enriched for single nucleotide variants that promote or eliminate FOS binding in human neurons. Disrupting the function of individual species-biased FOS-bound enhancers diminishes expression of nearby genes and affects the firing dynamics of human neurons. Our findings indicate that FOS-bound enhancers are frequent sites of evolution and that they regulate human-specific ADGs that may contribute to the unusually protracted and complex process of postnatal human brain development.

evolutionary biology↗

bioRxiv2025

Human-chimpanzee tetraploid system defines mechanisms of species-specific neural gene regulation

A major challenge in human evolutionary biology is to pinpoint genetic differences that underlie human-specific traits, such as increased neuron number and differences in cognitive behaviors. We used human-chimpanzee tetraploid cells to distinguish gene expression changes due to cis-acting sequence variants that change local gene regulation, from trans expression changes due to species differences in the cellular environment. In neural progenitor cells, examination of both cis and trans changes -- combined with CRISPR inhibition and transcription factor motif analyses -- identified cis-acting, species-specific gene regulatory changes, including to TNIK, FOSL2, and MAZ, with widespread trans effects on neurogenesis-related gene programs. In excitatory neurons, we identified POU3F2 as a key cis-regulated gene with trans effects on synaptic gene expression and neuronal firing. This study identifies cis-acting genomic changes that cause cascading trans gene regulatory effects to contribute to human neural specializations, and provides a general framework for discovering genetic differences underlying human traits.

evolutionary biology↗

bioRxiv2025

Structural basis for the midnolin-proteasome pathway and its role in suppressing myeloma

The midnolin-proteasome pathway degrades many nuclear proteins without ubiquitination, but how it operates mechanistically remains unclear. Here, we present structures of the midnolin-proteasome complex, revealing how established proteasomal components are repurposed to enable a unique form of proteolysis. While the proteasomal subunit PSMD2/Rpn1 binds to ubiquitinated or ubiquitin-like proteins, we discover that it also interacts with the midnolin nuclear localization sequence, elucidating how midnolins activity is confined to the nucleus. Likewise, PSMD14/Rpn11, an enzyme that normally cleaves ubiquitin chains, surprisingly functions non-enzymatically as a receptor for the midnolin ubiquitin-like (Ubl) domain, positioning the substrate-binding Catch domain directly above the proteasomal entry site to guide substrates into the proteasome. Moreover, we demonstrate that midnolin downregulation is critical for the survival of myeloma cells by promoting the expression of its transcription factor substrate IRF4. Our findings uncover the mechanisms underlying the midnolin-proteasome pathway and midnolin downregulation as a driver of multiple myeloma.

cell biology↗

bioRxiv2024

Cell-specific delivery of GJB2 restores auditory function in mouse models of DFNB1 deafness and mediates appropriate expression in NHP cochlea

Mutations in the GJB2 gene cause the most common form of human hereditary hearing loss, known as DFNB1. GJB2 is expressed in two cell groups of the cochlea--epithelial cells of the organ of Corti and fibrocytes of the inner sulcus and lateral wall--but not by sensory hair cells or neurons. Attempts to treat mouse models of DFNB1 with AAV vectors mediating nonspecific Gjb2 expression have not substantially restored function, perhaps because inappropriate expression in hair cells and neurons could compromise their electrical activity. Here, we used genomic chromatin accessibility profiling to identify candidate gene regulatory elements (GREs) that could drive cell-type-specific expression of Gjb2 in the cochlea. HA-tagged GJB2, delivered to a conditional knockout model in an AAV vector with GRE control of expression, was localized to the appropriate cell types, prevented the cochlear degeneration observed in untreated knockout mice, and partially rescued hearing sensitivity. In a Gjb2 partial knockdown mouse model, such exogenous GJB2 prevented degeneration and completely restored hearing sensitivity. We tested control of expression by these GREs in nonhuman primate cochleas and found that vector-delivered human GJB2.HA was located in the appropriate cell types and caused little or no reduction in hearing sensitivity. Together, these findings suggest that GRE-mediated expression of GJB2 could prevent hearing loss in DFNB1 patients.

neuroscience↗

bioRxiv2024

Novel environment exposure drives temporally defined and region-specific chromatin accessibility and gene expression changes in the hippocampus

The interaction of mammals with a novel environment (NE) results in structural and functional changes in multiple brain areas, including the hippocampus. This experience-dependent circuit reorganization is driven in part by changes in gene expression however, the dynamic sensory experience-driven chromatin states and the diverse cell type specific gene expression programs that are regulated by novel experiences are not well described. We employed single- nucleus multiomics (snRNA- and ATAC-seq) and bulk RNA-seq of the hippocampal DG, CA3, and CA1 regions to characterize the temporal evolution of cell-type-specific chromatin accessibility and gene expression changes that occur in 14 different cell types of the hippocampus upon exposure of mice to a novel environment. We observe strong hippocampal regional specificity in excitatory neuron chromatin accessibility and gene expression as well as great diversity in the inhibitory neuron and non-neuronal transcriptional responses. The novel environment-regulated genes in each cell type were enriched for genes that encode secreted factors, and cell-type-specific expression of their cognate receptors identified promising candidates for the modulation of learning and memory processes. Our characterization of the effect of novel experience on chromatin revealed thousands of cell-type-specific changes in chromatin accessibility. Coordinated analysis of chromatin accessibility and gene expression changes within individual cell types identified Fos/AP-1 as a key driver of novel experience-induced changes in chromatin accessibility and cell-type-specific gene expression. Together, these data provide a rich resource of hippocampal chromatin accessibility and gene expression profiles across diverse cell types in response to novel experience, a physiological stimulus that affects learning and memory.

neuroscience↗

bioRxiv2024

Cis-regulatory elements driving motor neuron-restricted viral payload expression within the mammalian spinal cord

Spinal motor neuron (MN) dysfunction is the cause of a number of clinically significant movement disorders. Despite the recent approval of gene therapeutics targeting these MN-related disorders, there are no viral delivery mechanisms that achieve MN-restricted transgene expression. In this study, chromatin accessibility profiling of genetically defined mouse MNs was used to identify candidate cis-regulatory elements (CREs) capable of driving MN-selective gene expression. Subsequent testing of these candidates identified two CREs that confer MN-selective gene expression in the spinal cord as well as reduced off-target expression in dorsal root ganglia. Within one of these candidate elements, we identified a compact core transcription factor (TF)-binding region that drives MN-selective gene expression. Finally, we demonstrate that selective spinal cord expression of this mouse CRE is preserved in non-human primates. These findings suggest that the generation of cell-type-selective viral reagents, in which cell-type-selective CREs drive restricted gene expression, will be valuable research tools in mice and other mammalian species, with potentially significant therapeutic value in humans. SIGNIFICANCE STATEMENTMotor neurons transduce the motor outputs of nervous system activity to muscle and are the vulnerable neurons in a number of clinically significant degenerative conditions, including spinal muscular atrophy and amyotrophic lateral sclerosis. A recent strategy for treating motor neuron degenerative diseases has been to use viruses to introduce genes into motor neurons to inhibit the degenerative process. However, we still lack viral reagents that promote gene expression in motor neurons without potentially toxic off-target expression in other cell types. Our study identifies cis-regulatory elements capable of conferring motor neuron-selective transgene expression in a viral context. These findings have important implications for future gene therapeutics for motor neuron-related disorders.

neuroscience↗

bioRxiv2024

Experience instructs the refinement of feature-selectivity in the mouse primary visual thalamus

Neurons exhibit selectivity for specific features: a property essential for extracting and encoding relevant information in the environment. This feature-selectivity is thought to be modifiable by experience at the level of the cortex. Here, we demonstrate that selective exposure to a feature during development can instruct the population representation for that feature in the primary visual thalamus. This thalamic plasticity is not simply inherited from the cortex because it is still observed when recordings were performed in the absence of cortical feedback. Moreover, plasticity is blocked in mutant mice that exhibit deficits in retinogeniculate refinement, indicating that alterations in feature-selectivity are a direct result of changes in feedforward connectivity. These experience-dependent changes persist into older ages--highlighting the importance of this developmental period in shaping population coding in the thalamus. Our results show that salient environmental features are hard-wired into thalamic circuits during a discrete developmental window.

neuroscience↗

bioRxiv2023

Activity-Induced MeCP2 Phosphorylation Regulates Retinogeniculate Synapse Refinement

Mutations in MECP2 give rise to Rett syndrome (RTT), an X-linked neurodevelopmental disorder that results in broad cognitive impairments in females. While the exact etiology of RTT symptoms remains unknown, one possible explanation for its clinical presentation is that loss of MeCP2 causes miswiring of neural circuits due to defects in the brains capacity to respond to changes in neuronal activity and sensory experience. Here we show that MeCP2 is phosphorylated at four residues in the brain (S86, S274, T308, and S421) in response to neuronal activity, and we generate a quadruple knock-in (QKI) mouse line in which all four activity-dependent sites are mutated to alanines to prevent phosphorylation. QKI mice do not display overt RTT phenotypes or detectable gene expression changes in two brain regions. However, electrophysiological recordings from the retinogeniculate synapse of QKI mice reveal that while synapse elimination is initially normal at P14, it is significantly compromised at P20. Notably, this phenotype is distinct from that previously reported for Mecp2 null mice, where synapses initially refine but then regress after the third postnatal week. We thus propose a model in which activity-induced phosphorylation of MeCP2 is critical for the proper timing of retinogeniculate synapse maturation specifically during the early postnatal period. SIGNIFICANCE STATEMENTRett syndrome (RTT) is an X-linked neurodevelopmental disorder that predominantly affects girls. RTT is caused by loss of function mutations in a single gene MeCP2. Girls with RTT develop normally during their first year of life, but then experience neurological abnormalities including breathing and movement difficulties, loss of speech, and seizures. This study investigates the function of the MeCP2 protein in the brain, and how MeCP2 activity is modulated by sensory experience in early life. Evidence is presented that sensory experience affects MeCP2 function, and that this is required for synaptic pruning in the brain. These findings provide insight into MeCP2 function, and clues as to what goes awry in the brain when the function of MeCP2 is disrupted.

neuroscience↗

bioRxiv2021

Characterization of sequence determinants of enhancer function using natural genetic variation

Sequence variation in enhancers, a class of cis-regulatory elements that control cell type-specific gene transcription, contributes significantly to phenotypic variation within human populations. Enhancers are short DNA sequences ([~]200 bp) composed of multiple binding sites (4-10 bp) for transcription factors (TFs). The transcriptional regulatory activity of an enhancer is encoded by the type, number, and distribution of TF binding sites that it contains. However, the sequence determinants of TF binding to enhancers and the relationship between TF binding and enhancer activity are complex, and thus it remains difficult to predict the effect of any given sequence variant on enhancer function. Here, we generate allele-specific maps of TF binding and enhancer activity in fibroblasts from a panel of F1 hybrid mice that have a high frequency of sequence variants. We identified thousands of enhancers that exhibit differences in TF binding and/or activity between alleles and use these data to define features of sequence variants that are most likely to impact enhancer function. Our data demonstrate a critical role for AP-1 TFs at many fibroblast enhancers, reveal a hierarchical relationship between AP-1 and TEAD TF binding at enhancers, and delineate the nature of sequence variants that contribute to AP-1 TF binding. These data represent one of the most comprehensive assessments to date of the impact of sequence variation on enhancer function in chromatin, with implications for identifying functional cis-regulatory variation in human populations.

genomics↗

bioRxiv2021

Developmental Dynamics of RNA Translation in the Human Brain

The precise regulation of gene expression is fundamental to neurodevelopment, plasticity, and cognitive function. While several studies have deeply profiled mRNA dynamics in the developing human brain, there is a fundamental gap in our understanding of accompanying translational regulation. We perform ribosome profiling from more than 70 human prenatal and adult cortex samples across ontogeny and into adulthood, mapping translation events at nucleotide resolution. In addition to characterizing the translational regulation of annotated open reading frames (ORFs), we identify thousands of previously unknown translation events, including small open reading frames (sORFs) that give rise to human- and/or brain-specific microproteins, many of which we independently verify using size-selected proteomics. Ribosome profiling in stem cell-derived human neuronal cultures further corroborates these findings and shows that several neuronal activity-induced long non-coding RNAs (lncRNAs), including LINC00473, a primate-specific lncRNA implicated in depression, encode previously undescribed microproteins. Physicochemical analysis of these brain microproteinss identifies a large class harboring arginine-glycine-glycine (RGG) repeats as strong candidates for regulating RNA metabolism. Moreover, we find that, collectively, these previously unknown human brain sORFs are enriched for variants associated with schizophrenia. In addition to significantly expanding the translational landscape of the developing brain, this atlas will serve as a rich resource for the annotation and functional interrogation of thousands of previously unknown brain-specific protein products.

neuroscience↗

bioRxiv2020

Proteomic analysis identifies the E3 ubiquitin ligase Pdzrn3 as a regulatory target of Wnt5a-Ror signaling

Wnt5a-Ror signaling is a conserved pathway that regulates morphogenetic processes during vertebrate development, but its downstream signaling events remain poorly understood. Through a large-scale proteomic screen in mouse embryonic fibroblasts, we identified the E3 ubiquitin ligase Pdzrn3 as a regulatory target of the Wnt5a-Ror pathway. Upon pathway activation, Pdzrn3 is degraded in a {beta}-catenin-independent, ubiquitin-proteasome system-dependent manner. We developed a flow cytometry-based reporter to monitor Pdzrn3 abundance and delineated a signaling cascade involving Frizzled, Dishevelled, CK1, and GSK3 that regulates Pdzrn3 stability. Epistatically, Pdzrn3 is regulated independently of Kif26b, another Wnt5a-Ror effector. Wnt5a-dependent degradation of Pdzrn3 requires phosphorylation of three conserved amino acids within its C-terminal LNX3H domain, which acts as a bona fide Wnt5a-responsive element. Importantly, this phospho-dependent degradation is essential for Wnt5a-Ror modulation of cell migration. Collectively, this work establishes a new Wnt5a-Ror cell morphogenetic cascade involving Pdzrn3 phosphorylation and degradation.

developmental biology↗

bioRxiv2019

PESCA: A scalable platform for the development of cell-type-specific viral drivers

Enhancers are the primary DNA regulatory elements that confer cell type specificity of gene expression. Recent studies characterizing individual enhancers have revealed their potential to direct heterologous gene expression in a highly cell-type-specific manner. However, it has not yet been possible to systematically identify and test the function of enhancers for each of the many cell types in an organism. We have developed PESCA, a scalable and generalizable method that leverages ATAC- and single-cell RNA-sequencing protocols, to characterize cell-type-specific enhancers that should enable genetic access and perturbation of gene function across mammalian cell types. Focusing on the highly heterogeneous mammalian cerebral cortex, we apply PESCA to find enhancers and generate viral reagents capable of accessing and manipulating a subset of somatostatin-expressing cortical interneurons with high specificity. This study demonstrates the utility of this platform for developing new cell-type-specific viral reagents, with significant implications for both basic and translational research.\n\nOne sentence summaryHighly paralleled functional evaluation of enhancer activity in single cells generates new cell-type-specific tools with broad medical and scientific applications.

neuroscience↗

bioRxiv2019

Sensory lesioning induces microglial synapse elimination via ADAM10 and fractalkine signaling

Microglia rapidly respond to changes in neural activity and inflammation to regulate synaptic connectivity. The extracellular signals, particularly neuron-derived molecules, that drive these microglial functions at synapses remains a key open question. Here, whisker lesioning, known to dampen cortical activity, induces microglia-mediated synapse elimination. We show that this synapse elimination is dependent on the microglial fractalkine receptor, CX3CR1, but not complement receptor 3, signaling. Further, mice deficient in the CX3CR1 ligand (CX3CL1) also have profound defects in synapse elimination. Single-cell RNAseq then revealed that Cx3cl1 is cortical neuron-derived and ADAM10, a metalloprotease that cleaves CX3CL1 into a secreted form, is upregulated specifically in layer IV neurons and microglia following whisker lesioning. Finally, inhibition of ADAM10 phenocopies Cx3cr1-/- and Cx3cl1-/- synapse elimination defects. Together, these results identify novel neuron-to-microglia signaling necessary for cortical synaptic remodeling and reveal context-dependent immune mechanisms are utilized to remodel synapses in the mammalian brain.

neuroscience↗