scholarly journals Tissue-specific regulation of epidermal contraction during C. elegans embryonic morphogenesis

2021 ◽  
Author(s):  
Elizabeth D Drewnik ◽  
Tobias Wiesenfahrt ◽  
Ryan B Smit ◽  
Ye-Jean Park ◽  
Linda M Pallotto ◽  
...  
Keyword(s):  
Rho Kinase ◽  
The Other ◽  
Cell Type ◽  
Tissue Specific ◽  
C Elegans ◽  
Lateral Contraction ◽  
Embryonic Morphogenesis ◽  
Specific Regulation ◽  
Primary Focus ◽  
P21 Activated Kinase

Abstract Actin and myosin mediate the epidermal cell contractions that elongate the Caenorhabditis elegans embryo from an ovoid to a tubular-shaped worm. Contraction occurs mainly in the lateral epidermal cells, while the dorsoventral epidermis plays a more passive role. Two parallel pathways trigger actinomyosin contraction, one mediated by LET-502/Rho kinase and the other by PAK-1/p21 activated kinase. A number of genes mediating morphogenesis have been shown to be sufficient when expressed either laterally or dorsoventrally. Additional genes show either lateral or dorsoventral phenotypes. This led us to a model where contractile genes have discrete functions in one or the other cell type. We tested this by examining several genes for either lateral or dorsoventral sufficiency. LET-502 expression in the lateral cells was sufficient to drive elongation. MEL-11/Myosin phosphatase, which antagonizes contraction, and PAK-1 were expected to function dorsoventrally, but we could not detect tissue-specific sufficiency. Double mutants of lethal alleles predicted to decrease lateral contraction with those thought to increase dorsoventral force were previously shown to be viable. We hypothesized that these mutant combinations shifted the contractile force from the lateral to the dorsoventral cells and so the embryos would elongate with less lateral cell contraction. This was tested by examining ten single and double mutant strains. In most cases, elongation proceeded without a noticeable alteration in lateral contraction. We suggest that many embryonic elongation genes likely act in both lateral and dorsoventral cells, even though they may have their primary focus in one or the other cell type.

scholarly journals Comprehensive characterization of tissue-specific chromatin accessibility in L2 Caenorhabditis elegans nematodes

2020 ◽  
Author(s):  
Timothy J. Durham ◽  
Riza M. Daza ◽  
Louis Gevirtzman ◽  
Darren A. Cusanovich ◽  
William Stafford Noble ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Expression Patterns ◽  
Cell Types ◽  
Chromatin Accessibility ◽  
Gene Expression Patterns ◽  
Rna Seq ◽  
Cell Type ◽  
Tissue Specific ◽  
C Elegans

AbstractRecently developed single cell technologies allow researchers to characterize cell states at ever greater resolution and scale. C. elegans is a particularly tractable system for studying development, and recent single cell RNA-seq studies characterized the gene expression patterns for nearly every cell type in the embryo and at the second larval stage (L2). Gene expression patterns are useful for learning about gene function and give insight into the biochemical state of different cell types; however, in order to understand these cell types, we must also determine how these gene expression levels are regulated. We present the first single cell ATAC-seq study in C. elegans. We collected data in L2 larvae to match the available single cell RNA-seq data set, and we identify tissue-specific chromatin accessibility patterns that align well with existing data, including the L2 single cell RNA-seq results. Using a novel implementation of the latent Dirichlet allocation algorithm, we leverage the single-cell resolution of the sci-ATAC-seq data to identify accessible loci at the level of individual cell types, providing new maps of putative cell type-specific gene regulatory sites, with promise for better understanding of cellular differentiation and gene regulation in the worm.

scholarly journals Acinus integrates AKT1 and subapoptotic caspase activities to regulate basal autophagy

2014 ◽  
Vol 207 (2) ◽  
pp. 253-268 ◽  
Author(s):  
Nilay Nandi ◽  
Lauren K. Tyra ◽  
Drew Stenesen ◽  
Helmut Krämer
Keyword(s):  
The Other ◽  
Caspase Activity ◽  
Starvation Resistance ◽  
Cell Type ◽  
Caspase Cleavage ◽  
Autophagy Induction ◽  
Caspase Cleavage Site ◽  
Cell Type Specific ◽  
Specific Regulation ◽  
Cellular Stresses

How cellular stresses up-regulate autophagy is not fully understood. One potential regulator is the Drosophila melanogaster protein Acinus (Acn), which is necessary for autophagy induction and triggers excess autophagy when overexpressed. We show that cell type–specific regulation of Acn depends on proteolysis by the caspase Dcp-1. Basal Dcp-1 activity in developing photoreceptors is sufficient for this cleavage without a need for apoptosis to elevate caspase activity. On the other hand, Acn was stabilized by loss of Dcp-1 function or by the presence of a mutation in Acn that eliminates its conserved caspase cleavage site. Acn stability also was regulated by AKT1-mediated phosphorylation. Flies that expressed stabilized forms of Acn, either the phosphomimetic AcnS641,731D or the caspase-resistant AcnD527A, exhibited enhanced basal autophagy. Physiologically, these flies showed improvements in processes known to be autophagy dependent, including increased starvation resistance, reduced Huntingtin-induced neurodegeneration, and prolonged life span. These data indicate that AKT1 and caspase-dependent regulation of Acn stability adjusts basal autophagy levels.

scholarly journals Homeoproteins CDP and SATB1 Interact: Potential for Tissue-Specific Regulation

1999 ◽  
Vol 19 (7) ◽  
pp. 4918-4926 ◽  
Author(s):  
Jinqi Liu ◽  
Anna Barnett ◽  
Ellis J. Neufeld ◽  
Jaquelin P. Dudley
Keyword(s):  
T Cells ◽  
Dna Binding ◽  
Promoter Region ◽  
Cell Type ◽  
Tissue Specific ◽  
Specific Antisera ◽  
Mmtv Promoter ◽  
Specific Regulation

ABSTRACT Homeoproteins are known to participate in development and cell type specification. The homeoproteins CCAAT displacement protein (CDP) and special AT-rich sequence binding protein 1 (SATB1) have been shown to bind to nuclear matrix-associated regions and to act as repressors of many cellular genes. Moreover, binding of SATB1 to the mouse mammary tumor virus (MMTV) promoter region dramatically affects the tissue-specific transcription of this retrovirus. Because protein-protein interactions are a common means of regulating homeoprotein function, we tested whether SATB1 and CDP interact in vivo and in vitro. SATB1 interacted with CDP through its DNA-binding domain, as demonstrated by glutathione S-transferase (GST) pull-down assays. GST pull-down assays also showed that CDP associated with SATB1 through three of its four DNA-binding domains (CR1, CR2, and the homeodomain). SATB1-specific antisera, but not preimmune sera, precipitated CDP from nuclear extracts, and CDP-specific antisera precipitated SATB1 from the same extracts. Far-Western blotting detected interaction of SATB1 and CDP in several different tissue extracts. Association of purified SATB1 and CDP in vitro resulted in the inability of each protein to bind to DNA in gel retardation assays. CDP overexpression in cultured T cells led to a loss of detectable SATB1 binding to the MMTV promoter region, as measured by gel shift experiments. CDP overexpression also elevated MMTV long terminal repeat reporter gene activity in transient-transfection assays, a result consistent with neutralization of the SATB1 repressor function in T cells. SATB1 is very abundant in certain tissues, particularly thymus, whereas CDP is relatively ubiquitous, except in certain terminally differentiated cell types. Because of the tissue and cell type distribution of SATB1 and CDP, we propose that the SATB1-to-CDP ratio in different tissues is a novel mechanism for homeoproteins to control gene expression and differentiation in mammals.

scholarly journals Tissue-specific safety mechanism results in opposite protein aggregation patterns during aging

2020 ◽  
Author(s):  
Raimund Jung ◽  
Marie C. Lechler ◽  
Christian Rödelsperger ◽  
Waltraud Röseler ◽  
Ralf J. Sommer ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Protein Quality ◽  
Core Protein ◽  
Lysosomal Degradation ◽  
Tissue Specific ◽  
C Elegans ◽  
Safety Mechanism ◽  
Pharyngeal Muscles ◽  
Specific Regulation ◽  
Pathogen Response

AbstractDuring aging, proteostasis capacity declines and aggregation-prone proteins become instable, accumulating in protein aggregates both inside and outside cells. Both in disease and during aging, proteins selectively aggregate in certain tissues and not others. Yet, tissue-specific regulation of protein aggregation remains poorly understood. Surprisingly, we found that the inhibition of three core protein quality control systems, i.e. chaperones, proteasome and macroautophagy, leads to lower levels of age-dependent protein aggregation in C. elegans pharyngeal muscles, but higher levels in body-wall muscles. We describe a novel safety mechanism called SAPA that selectively targets newly synthesized aggregation-prone proteins to suppress aggregation and proteotoxicity. vha-12 and scav-3 mutants reveal that SAPA relies on macroautophagy-independent lysosomal degradation. Furthermore, SAPA involves several previously uncharacterized components of the intracellular pathogen response. We propose that SAPA represents an anti-aggregation machinery targeting aggregation-prone proteins for lysosomal degradation.

A Single-copy Knock In Translating Ribosome ImmunoPrecipitation (SKI TRIP) tool kit for tissue specific profiling of actively translated mRNAs in C. elegans.

2021 ◽  
Author(s):  
Laura E Wester ◽  
Anne Lanjuin ◽  
Emanuel H W Bruckisch ◽  
Maria C Perez Matos ◽  
Caroline Heintz ◽  
...  
Keyword(s):  
Affinity Purification ◽  
Ribosomal Subunit ◽  
Mrna Translation ◽  
Single Copy ◽  
Specific Cell ◽  
Cell Type ◽  
Specific Expression ◽  
Tissue Specific ◽  
C Elegans ◽  
Cell Type Specific

Translating Ribosome Affinity Purification (TRAP) methods have emerged as a powerful approach to profile actively translated transcripts in specific cell and tissue types. Epitope tagged ribosomal subunits are expressed in defined cell populations and used to pull down ribosomes and their associated mRNAs, providing a snapshot of cell type-specific translation occurring in that space and time. Current TRAP toolkits available to the C. elegans community have been built using multi-copy arrays, randomly integrated in the genome. Here we introduce a Single-copy Knock In Translating Ribosome ImmunoPrecipitation (SKI TRIP) tool kit, a collection of C. elegans strains engineered by CRISPR in which tissue specific expression of FLAG tagged ribosomal subunit protein RPL-22 is driven by cassettes present in single copy from defined sites in the genome. In depth characterization of the SKI TRIP strains and methodology shows that 3xFLAG tagged RPL-22 expressed from its endogenous locus or within defined cell types incorporates into actively translating ribosomes and can be used to efficiently and cleanly pull-down cell type specific transcripts without impacting overall mRNA translation or fitness of the animal. We propose SKI TRIP use for the study of processes that are acutely sensitive to changes in translation, such as aging.

scholarly journals Quantifying the Tissue-Specific Regulatory Information within Enhancer DNA Sequences

2021 ◽  
Author(s):  
Philipp Benner ◽  
Martin Vingron
Keyword(s):  
Dna Sequences ◽  
Cell Types ◽  
Cell Type ◽  
Regulate Gene Expression ◽  
Tissue Specific ◽  
Sequence Patterns ◽  
Cell Type Specific ◽  
Specific Regulation ◽  
Different Cell Types ◽  
Regulatory Landscape

AbstractRecent efforts to measure epigenetic marks across a wide variety of different cell types and tissues provide insights into the cell type-specific regulatory landscape. We use this data to study if there exists a correlate of epigenetic signals in the DNA sequence of enhancers and explore with computational methods to what degree such sequence patterns can be used to predict cell type-specific regulatory activity. By constructing classifiers that predict in which tissues enhancers are active, we are able to identify sequence features that might be recognized by the cell in order to regulate gene expression. While classification performances vary greatly between tissues, we show examples where our classifiers correctly predict tissue specific regulation from sequence alone. We also show that many of the informative patterns indeed harbor transcription factor footprints.

scholarly journals Organism-wide single-cell transcriptomics of long-lived C. elegans daf-2-/- mutants reveals tissue-specific reprogramming of gene expression networks

2019 ◽  
Author(s):  
Jessica L. Preston ◽  
Nicholas Stiffler ◽  
Maggie Weitzman
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Expression Profiles ◽  
Regulation Of Gene Expression ◽  
Gene Expression Profiles ◽  
Machine Learning Algorithms ◽  
Wild Type ◽  
Tissue Specific ◽  
C Elegans ◽  
Specific Regulation

AbstractA critical requirement for a systems-level understanding of complex biological processes such as aging is the ability to directly characterize interactions between cells and tissues within a multicellular organism. C. elegans nematodes harboring mutations in the insulin-like receptor daf-2 exhibit dramatically-increased lifespans. To identify tissue-specific biochemical mechanisms regulating aging plasticity, we single-cell sequenced 3’-mRNA libraries generated from seven populations of whole day-one adult wild-type and daf-2-/- worms using the 10x ChromiumV1™platform. The age-synchronized samples were bioinformatically merged into a single aligned dataset containing 40,000 age-synchronized wild-type and daf-2-/- cellular transcriptomes partitioned into 101 clusters, using unsupervised machine-learning algorithms to identify common cell types. Here we describe the basic features of the adult C. elegans single-cell transcriptome and summarize functional alterations observed in the gene expression profiles of long-lived daf-2-/- worms. Comprehensive methods and datasets are provided. This is the first study to directly quantify cell-specific differential gene expression between two age-synchronized, genetically-distinct populations of multicellular organisms. This novel approach answers fundamental questions regarding tissue-specific regulation of gene expression and helps to establish a foundation for a comprehensive C. elegans single-cell gene expression atlas.

scholarly journals Cell-type specific regulation of serotonergic identity by the C. elegans LIM-homeodomain factor LIM-4

2005 ◽  
Vol 286 (2) ◽  
pp. 618-628 ◽  
Author(s):  
Xianwu Zheng ◽  
Shinjae Chung ◽  
Takahiro Tanabe ◽  
Ji Ying Sze
Keyword(s):  
Cell Type ◽  
C Elegans ◽  
Cell Type Specific ◽  
Specific Regulation ◽  
Lim Homeodomain

scholarly journals Four distinct regulatory regions of the cut locus and their effect on cell type specification in Drosophila.

Genetics ◽  
1991 ◽  
Vol 127 (1) ◽  
pp. 151-159 ◽  
Author(s):  
S Liu ◽  
E McLeod ◽  
J Jack
Keyword(s):  
Regulatory Region ◽  
Malpighian Tubules ◽  
The Other ◽  
Cell Type ◽  
Cut Locus ◽  
Sensory Organs ◽  
Regulatory Regions ◽  
Tissue Specific ◽  
Specific Effects ◽  
Type Specification

Abstract The cut gene in Drosophila is necessary in at least one cell type, the external sensory organs, for proper cell type specification and morphogenesis. It is also expressed in a variety of other tissues, where its function is less well characterized. Previous work has demonstrated that mutations affecting all the tissues map in the transcribed and translated portion of the gene, while mutations that are tissue specific in their effects map in the 140 kb upstream of the most 5' exon known. Within that 140 kb, the mutations fall into four subregions, two of which contain mutations affecting unique sets of tissues and the other two of which contain mutations that affect a third set. Our examination of the defects of mutants, their complementation behavior, and their effect on the distribution of the cut protein in embryos, alters the picture in three important ways. First, some mutations convert the cells of the Malpighian tubules into what appear to be gut cells, suggesting that cut is necessary for cell type specification and morphogenesis in a variety of tissues. Second, mutations in each of the four subregions in the 140 kb of upstream DNA cause a different set of phenotypes, suggesting that the regulatory region contains at least four separate units with different tissue specific functions. And third, mutations have now been identified that map in the transcribed and translated portion of the gene but that have tissue specific effects.

scholarly journals Quantifying the tissue-specific regulatory information within enhancer DNA sequences

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Philipp Benner ◽  
Martin Vingron
Keyword(s):  
Dna Sequences ◽  
Cell Types ◽  
Cell Type ◽  
Regulate Gene Expression ◽  
Tissue Specific ◽  
Sequence Patterns ◽  
Cell Type Specific ◽  
Specific Regulation ◽  
Different Cell Types ◽  
Regulatory Landscape

Abstract Recent efforts to measure epigenetic marks across a wide variety of different cell types and tissues provide insights into the cell type-specific regulatory landscape. We use these data to study whether there exists a correlate of epigenetic signals in the DNA sequence of enhancers and explore with computational methods to what degree such sequence patterns can be used to predict cell type-specific regulatory activity. By constructing classifiers that predict in which tissues enhancers are active, we are able to identify sequence features that might be recognized by the cell in order to regulate gene expression. While classification performances vary greatly between tissues, we show examples where our classifiers correctly predict tissue-specific regulation from sequence alone. We also show that many of the informative patterns indeed harbor transcription factor footprints.

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