scholarly journals Extensive Involvement of Alternative Polyadenylation in Single-Nucleus Neurons

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 709
Author(s):  
Ying Wang ◽  
Weixing Feng ◽  
Siwen Xu ◽  
Bo He
Keyword(s):  
Rna Binding ◽  
Neuronal Cell ◽  
Alternative Polyadenylation ◽  
Cell Types ◽  
Inhibitory Neurons ◽  
Cell Populations ◽  
Motif Analysis ◽  
Eukaryotic Genes ◽  
Single Nucleus ◽  
Extensive Involvement

Cleavage and polyadenylation are essential processes that can impact many aspects of mRNA fate. Most eukaryotic genes have alternative polyadenylation (APA) events. While the heterogeneity of mRNA polyadenylation isoform choice has been studied in specific tissues, less attention has been paid to the neuronal heterogeneity of APA selection at single-nucleus resolution. APA is highly controlled during development and neuronal activation, however, to what extent APA events vary in a specific neuronal cell population and the regulatory mechanisms are still unclear. In this paper, we investigated dynamic APA usage in different cell types using snRNA-seq data of 1424 human brain cells generated by single-cell 3′ RNA sequencing. We found that distal APA sites are not only favored by global neuronal cells, but that their usage also varies between the principal types of neuronal cell populations (excitatory neurons and inhibitory neurons). A motif analysis and a gene functional analysis indicated the enrichment of RNA-binding protein (RBP) binding sites and neuronal functions for the set of genes with neuron-enhanced distal PAS usage. Our results revealed the extensive involvement of APA regulation in neuronal populations at the single-nucleus level, providing new insights into roles for APA in specific neuronal cell populations, as well as utility in future functional studies.

scholarly journals The landscape of alternative polyadenylation in single cells of the developing mouse embryo

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Vikram Agarwal ◽  
Sereno Lopez-Darwin ◽  
David R. Kelley ◽  
Jay Shendure
Keyword(s):  
Rna Binding ◽  
Developmental Stages ◽  
Single Cells ◽  
Neuronal Cell ◽  
Alternative Polyadenylation ◽  
Cell Types ◽  
Untranslated Regions ◽  
Mammalian Development ◽  
Translation Rate ◽  
Dynamic Landscape

Abstract3′ untranslated regions (3′ UTRs) post-transcriptionally regulate mRNA stability, localization, and translation rate. While 3′-UTR isoforms have been globally quantified in limited cell types using bulk measurements, their differential usage among cell types during mammalian development remains poorly characterized. In this study, we examine a dataset comprising ~2 million nuclei spanning E9.5–E13.5 of mouse embryonic development to quantify transcriptome-wide changes in alternative polyadenylation (APA). We observe a global lengthening of 3′ UTRs across embryonic stages in all cell types, although we detect shorter 3′ UTRs in hematopoietic lineages and longer 3′ UTRs in neuronal cell types within each stage. An analysis of RNA-binding protein (RBP) dynamics identifies ELAV-like family members, which are concomitantly induced in neuronal lineages and developmental stages experiencing 3′-UTR lengthening, as putative regulators of APA. By measuring 3′-UTR isoforms in an expansive single cell dataset, our work provides a transcriptome-wide and organism-wide map of the dynamic landscape of alternative polyadenylation during mammalian organogenesis.

scholarly journals Single Cell, Single Nucleus and Spatial RNA Sequencing of the Human Liver Identifies Hepatic Stellate Cell and Cholangiocyte Heterogeneity

2021 ◽  
Author(s):  
Tallulah S Andrews ◽  
Jawairia Atif ◽  
Jeff C Liu ◽  
Catia T Perciani ◽  
Xue-Zhong Ma ◽  
...  
Keyword(s):  
Single Cell ◽  
Rna Sequencing ◽  
Human Liver ◽  
Stellate Cell ◽  
Parenchymal Cell ◽  
Cell Types ◽  
Cell Populations ◽  
Healthy Human ◽  
Single Nucleus

The critical functions of the human liver are coordinated through the interactions of hepatic parenchymal and non-parenchymal cells. Recent advances in single cell transcriptional approaches have enabled an examination of the human liver with unprecedented resolution. However, dissociation related cell perturbation can limit the ability to fully capture the human liver's parenchymal cell fraction, which limits the ability to comprehensively profile this organ. Here, we report the transcriptional landscape of 73,295 cells from the human liver using matched single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA sequencing (snRNA-seq). The addition of snRNA-seq enabled the characterization of interzonal hepatocytes at single-cell resolution, revealed the presence of rare subtypes of hepatic stellate cells previously only seen in disease, and detection of cholangiocyte progenitors that had only been observed during in vitro differentiation experiments. However, T and B lymphocytes and NK cells were only distinguishable using scRNA-seq, highlighting the importance of applying both technologies to obtain a complete map of tissue-resident cell-types. We validated the distinct spatial distribution of the hepatocyte, cholangiocyte and stellate cell populations by an independent spatial transcriptomics dataset and immunohistochemistry. Our study provides a systematic comparison of the transcriptomes captured by scRNA-seq and snRNA-seq and delivers a high-resolution map of the parenchymal cell populations in the healthy human liver.

scholarly journals Prevalent presence of periodic actin–spectrin-based membrane skeleton in a broad range of neuronal cell types and animal species

2016 ◽  
Vol 113 (21) ◽  
pp. 6029-6034 ◽  
Author(s):  
Jiang He ◽  
Ruobo Zhou ◽  
Zhuhao Wu ◽  
Monica A. Carrasco ◽  
Peri T. Kurshan ◽  
...  
Keyword(s):  
Glial Cell ◽  
Animal Species ◽  
Homo Sapiens ◽  
Neuronal Cell ◽  
Cell Types ◽  
Membrane Skeleton ◽  
Brain Regions ◽  
Inhibitory Neurons ◽  
Periodic Distribution ◽  
Neuronal Types

Actin, spectrin, and associated molecules form a periodic, submembrane cytoskeleton in the axons of neurons. For a better understanding of this membrane-associated periodic skeleton (MPS), it is important to address how prevalent this structure is in different neuronal types, different subcellular compartments, and across different animal species. Here, we investigated the organization of spectrin in a variety of neuronal- and glial-cell types. We observed the presence of MPS in all of the tested neuronal types cultured from mouse central and peripheral nervous systems, including excitatory and inhibitory neurons from several brain regions, as well as sensory and motor neurons. Quantitative analyses show that MPS is preferentially formed in axons in all neuronal types tested here: Spectrin shows a long-range, periodic distribution throughout all axons but appears periodic only in a small fraction of dendrites, typically in the form of isolated patches in subregions of these dendrites. As in dendrites, we also observed patches of periodic spectrin structures in a small fraction of glial-cell processes in four types of glial cells cultured from rodent tissues. Interestingly, despite its strong presence in the axonal shaft, MPS is disrupted in most presynaptic boutons but is present in an appreciable fraction of dendritic spine necks, including some projecting from dendrites where such a periodic structure is not observed in the shaft. Finally, we found that spectrin is capable of adopting a similar periodic organization in neurons of a variety of animal species, including Caenorhabditis elegans, Drosophila, Gallus gallus, Mus musculus, and Homo sapiens.

scholarly journals Regulation, diversity and function of MECP2 exon and 3′UTR isoforms

2020 ◽  
Vol 29 (R1) ◽  
pp. R89-R99
Author(s):  
Deivid Carvalho Rodrigues ◽  
Marat Mufteev ◽  
James Ellis
Keyword(s):  
Dna Binding ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Alternative Polyadenylation ◽  
Cell Types ◽  
Protein Isoforms ◽  
Translation Efficiency ◽  
Mrna Isoforms ◽  
Exon 2 ◽  
Messenger Ribonucleic Acid

Abstract The methyl-CpG-binding protein 2 (MECP2) is a critical global regulator of gene expression. Mutations in MECP2 cause neurodevelopmental disorders including Rett syndrome (RTT). MECP2 exon 2 is spliced into two alternative messenger ribonucleic acid (mRNA) isoforms encoding MECP2-E1 or MECP2-E2 protein isoforms that differ in their N-termini. MECP2-E2, isolated first, was used to define the general roles of MECP2 in methyl-deoxyribonucleic acid (DNA) binding, targeting of transcriptional regulatory complexes, and its disease-causing impact in RTT. It was later found that MECP2-E1 is the most abundant isoform in the brain and its exon 1 is also mutated in RTT. MECP2 transcripts undergo alternative polyadenylation generating mRNAs with four possible 3′untranslated region (UTR) lengths ranging from 130 to 8600 nt. Together, the exon and 3′UTR isoforms display remarkable abundance disparity across cell types and tissues during development. These findings indicate discrete means of regulation and suggest that protein isoforms perform non-overlapping roles. Multiple regulatory programs have been explored to explain these disparities. DNA methylation patterns of the MECP2 promoter and first intron impact MECP2-E1 and E2 isoform levels. Networks of microRNAs and RNA-binding proteins also post-transcriptionally regulate the stability and translation efficiency of MECP2 3′UTR isoforms. Finally, distinctions in biophysical properties in the N-termini between MECP2-E1 and E2 lead to variable protein stabilities and DNA binding dynamics. This review describes the steps taken from the discovery of MECP2, the description of its key functions, and its association with RTT, to the emergence of evidence revealing how MECP2 isoforms are differentially regulated at the transcriptional, post-transcriptional and post-translational levels.

scholarly journals Crosstalk Between mRNA 3'-End Processing and Epigenetics

2021 ◽  
Vol 12 ◽  
Author(s):  
Lindsey V. Soles ◽  
Yongsheng Shi
Keyword(s):  
Histone Modifications ◽  
Dynamic Process ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Alternative Polyadenylation ◽  
Regulatory Mechanisms ◽  
Epigenetic Mechanisms ◽  
Cis Elements ◽  
Mrna Isoforms ◽  
Eukaryotic Genes

The majority of eukaryotic genes produce multiple mRNA isoforms by using alternative poly(A) sites in a process called alternative polyadenylation (APA). APA is a dynamic process that is highly regulated in development and in response to extrinsic or intrinsic stimuli. Mis-regulation of APA has been linked to a wide variety of diseases, including cancer, neurological and immunological disorders. Since the first example of APA was described 40 years ago, the regulatory mechanisms of APA have been actively investigated. Conventionally, research in this area has focused primarily on the roles of regulatory cis-elements and trans-acting RNA-binding proteins. Recent studies, however, have revealed important functions for epigenetic mechanisms, including DNA and histone modifications and higher-order chromatin structures, in APA regulation. Here we will discuss these recent findings and their implications for our understanding of the crosstalk between epigenetics and mRNA 3'-end processing.

scholarly journals Complexity and graded regulation of neuronal cell type-specific alternative splicing revealed by single-cell RNA sequencing

2021 ◽  
Author(s):  
Huijuan Feng ◽  
Daniel F. Moakley ◽  
Shuonan Chen ◽  
Melissa G. McKenzie ◽  
Vilas Menon ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Neuronal Cell ◽  
Cell Types ◽  
Mammalian Brain ◽  
Differential Splicing ◽  
Hierarchical Levels ◽  
Neuronal Types ◽  
And Function

AbstractThe enormous neuronal cellular diversity in the mammalian brain, which is highly prototypical and organized in a hierarchical manner, is dictated by cell type-specific gene regulatory programs at the molecular level. Although prevalent in the brain, contribution of alternative splicing (AS) to the molecular diversity across neuronal cell types is just starting to emerge. Here we systematically investigated AS regulation across over 100 transcriptomically defined neuronal types of the adult mouse cortex using deep single cell RNA-sequencing (scRNA-seq) data. We found distinct splicing programs between glutamatergic and GABAergic neurons and between subclasses within each neuronal class, consisting of overlapping sets of alternative exons showing differential splicing at multiple hierarchical levels. Using an integrative approach, our analysis suggests that RNA-binding proteins (RBPs) Celf1/2, Mbnl2 and Khdrbs3 are preferentially expressed and more active in glutamatergic neurons, while Elavl2 and Qk are preferentially expressed and more active in GABAergic neurons. Importantly, these and additional RBPs also contribute to differential splicing between neuronal subclasses at multiple hierarchical levels, and some RBPs drive splicing dynamics that do not conform to the hierarchical structure defined by the transcriptional profiles. Thus, our results suggest graded regulation of AS across neuronal cell types, which provides a molecular mechanism orthogonal to, rather than downstream of, transcriptional regulation in specifying neuronal identity and function.SignificanceAlternative splicing (AS) is extensively used in the mammalian brain, but its contribution to the molecular and cellular diversity across neuronal cell types remains poorly understood. Through systematic and integrative analysis of AS regulation across over 100 transcriptomically defined cortical neuronal types, we found neuronal subclass-specific splicing regulatory programs consists of overlapping alternative exons showing differential splicing at multiple hierarchical levels. This graded AS regulation is controlled by unique combinations of RNA-binding proteins (RBPs). Importantly, these RBPs also drive splicing dynamics across neuronal cell types that do not conform to the hierarchical taxonomy established based on transcriptional profiles, suggesting that the graded AS regulation provides a molecular mechanism orthogonal to transcriptional regulation in specifying neuronal identity and function.

scholarly journals Single-nuclei transcriptomics of schizophrenia prefrontal cortex primarily implicates neuronal subtypes

2020 ◽  
Author(s):  
Benjamin C. Reiner ◽  
Richard C. Crist ◽  
Lauren M. Stein ◽  
Andrew E. Weller ◽  
Glenn A. Doyle ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Differentially Expressed Genes ◽  
Neuronal Cell ◽  
Cell Types ◽  
Brain Regions ◽  
Differentially Expressed ◽  
Inhibitory Neurons ◽  
Specific Cell ◽  
Dorsolateral Prefrontal ◽  
Layer V

AbstractTranscriptomic studies of bulk neural tissue homogenates from persons with schizophrenia and controls have identified differentially expressed genes in multiple brain regions. However, the heterogeneous nature prevents identification of relevant cell types. This study analyzed single-nuclei transcriptomics of ∼311,000 nuclei from frozen human postmortem dorsolateral prefrontal cortex samples from individuals with schizophrenia (n = 14) and controls (n = 16). 2,846 differential expression events were identified in 2,195 unique genes in 19 of 24 transcriptomically-distinct cell populations. ∼97% of differentially expressed genes occurred in five neuronal cell types, with ∼63% occurring in a subtype of PVALB+ inhibitory neurons and HTR2C+ layer V excitatory neurons. Differentially expressed genes were enriched for genes localized to schizophrenia GWAS loci. Cluster-specific changes in canonical pathways, upstream regulators and causal networks were identified. These results expand our knowledge of disrupted gene expression in specific cell types and permit new insight into the pathophysiology of schizophrenia.

scholarly journals Equivalent high-resolution identification of neuronal cell types with single-nucleus and single-cell RNA-sequencing

2017 ◽  
Author(s):  
Trygve E. Bakken ◽  
Rebecca D. Hodge ◽  
Jeremy M. Miller ◽  
Zizhen Yao ◽  
Thuc N. Nguyen ◽  
...  
Keyword(s):  
High Resolution ◽  
Single Cell ◽  
Rna Sequencing ◽  
Transcriptional Profiling ◽  
Neuronal Cell ◽  
Cell Types ◽  
Matched Pair ◽  
Rna Seq ◽  
Nuclear Rna ◽  
Single Nucleus

AbstractTranscriptional profiling of complex tissues by RNA-sequencing of single nuclei presents some advantages over whole cell analysis. It enables unbiased cellular coverage, lack of cell isolation-based transcriptional effects, and application to archived frozen specimens. Using a well-matched pair of single-nucleus RNA-seq (snRNA-seq) and single-cell RNA-seq (scRNA-seq) SMART-Seq v4 datasets from mouse visual cortex, we demonstrate that similarly high-resolution clustering of closely related neuronal types can be achieved with both methods if intronic sequences are included in nuclear RNA-seq analysis. More transcripts are detected in individual whole cells (∼11,000 genes) than nuclei (∼7,000 genes), but the majority of genes have similar detection across cells and nuclei. We estimate that the nuclear proportion of total cellular mRNA varies from 20% to over 50% for large and small pyramidal neurons, respectively. Together, these results illustrate the high information content of nuclear RNA for characterization of cellular diversity in brain tissues.

scholarly journals FMRP has a cell-type-specific role in CA1 pyramidal neurons to regulate autism-related transcripts and circadian memory

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Kirsty Sawicka ◽  
Caryn R Hale ◽  
Christopher Y Park ◽  
John J Fak ◽  
Jodi E Gresack ◽  
...  
Keyword(s):  
Pyramidal Neurons ◽  
Rna Binding ◽  
Fragile X ◽  
Neuronal Cell ◽  
Cell Types ◽  
Brain Regions ◽  
Cell Type ◽  
Ca1 Pyramidal Neurons ◽  
Mrna Targets ◽  
Specific Regulation

Loss of the RNA binding protein FMRP causes Fragile X Syndrome (FXS), the most common cause of inherited intellectual disability, yet it is unknown how FMRP function varies across brain regions and cell types and how this contributes to disease pathophysiology. Here we use conditional tagging of FMRP and CLIP (FMRP cTag CLIP) to examine FMRP mRNA targets in hippocampal CA1 pyramidal neurons, a critical cell type for learning and memory relevant to FXS phenotypes. Integrating these data with analysis of ribosome-bound transcripts in these neurons revealed CA1-enriched binding of autism-relevant mRNAs, and CA1-specific regulation of transcripts encoding circadian proteins. This contrasted with different targets in cerebellar granule neurons, and was consistent with circadian defects in hippocampus-dependent memory in Fmr1 knockout mice. These findings demonstrate differential FMRP-dependent regulation of mRNAs across neuronal cell types that may contribute to phenotypes such as memory defects and sleep disturbance associated with FXS.

scholarly journals Cerebellar nuclei evolved by repeatedly duplicating a conserved cell type set

2020 ◽  
Author(s):  
Justus M Kebschull ◽  
Noam Ringach ◽  
Ethan B Richman ◽  
Drew Friedmann ◽  
Sai Saroja Kolluru ◽  
...  
Keyword(s):  
Brain Region ◽  
Cell Types ◽  
Cerebellar Nuclei ◽  
Inhibitory Neurons ◽  
Cell Type ◽  
Cell Class ◽  
Single Nucleus ◽  
Entire Cell ◽  
Region Evolution

AbstractHow have complex brains evolved from simple circuits? Here we investigated brain region evolution at cell type resolution in the cerebellar nuclei (CN), the output structures of the cerebellum. Using single-nucleus RNA sequencing in mice, chickens, and humans, as well as STARmap spatial transcriptomic analysis and whole-CNS projection tracing in mice, we identified a conserved cell type set containing two classes of region-specific excitatory neurons and three classes of region-invariant inhibitory neurons. This set constitutes an archetypal CN that was repeatedly duplicated to form new regions. Interestingly, the excitatory cell class that preferentially funnels information to lateral frontal cortices in mice becomes predominant in the massively expanded human Lateral CN. Our data provide the first characterization of CN transcriptomic cell types in three species and suggest a model of brain region evolution by duplication and divergence of entire cell type sets.

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