scholarly journals A sensitized genetic screen to identify regulators of C. elegans germline stem cells

2021 ◽  
Author(s):  
Sarah Robinson-Thiewes ◽  
Aaron M Kershner ◽  
Heaji Shin ◽  
Kimberly A Haupt ◽  
Peggy Kroll-Connor ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dna Polymerase ◽  
Transcriptional Activation ◽  
Regulatory Network ◽  
Genetic Screen ◽  
Germline Stem Cells ◽  
Meiotic Cell ◽  
Genetic Screens ◽  
C Elegans ◽  
Forward Genetic Screens

Abstract GLP-1/Notch signaling and a downstream RNA regulatory network maintain germline stem cells (GSCs) in Caenorhabditis elegans. In mutants lacking the GLP-1 receptor, all GSCs enter the meiotic cell cycle precociously and differentiate into sperm. This dramatic GSC defect is called the “Glp” phenotype. The lst-1 and sygl-1 genes are direct targets of Notch transcriptional activation and functionally redundant. Whereas single lst-1 and sygl-1 mutants are fertile, lst-1 sygl-1 double mutants are sterile with a Glp phenotype. We set out to identify genes that function redundantly with either lst-1 or sygl-1 to maintain GSCs. To this end, we conducted forward genetic screens for mutants with a Glp phenotype in genetic backgrounds lacking functional copies of either lst-1 or sygl-1. The screens generated nine glp-1 alleles, two lst-1 alleles, and one allele of pole-1, which encodes the catalytic subunit of DNA polymerase ε. Three glp-1 alleles reside in Ankyrin (ANK) repeats not previously mutated. pole-1 single mutants have a low penetrance Glp phenotype that is enhanced by loss of sygl-1. Thus, the screen uncovered one locus that interacts genetically with sygl-1 and generated useful mutations for further studies of GSC regulation.

A sensitized genetic screen to identify regulators of C. elegans germline stem cells

2021 ◽  
Author(s):  
Sarah Robinson-Thiewes ◽  
Aaron M. Kershner ◽  
Heaji Shin ◽  
Kimberly A. Haupt ◽  
Peggy Kroll-Connor ◽  
...  
Keyword(s):  
Stem Cells ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Gene Products ◽  
Germline Stem Cells ◽  
Loss Of Function ◽  
Genetic Screens ◽  
Self Renewal ◽  
C Elegans ◽  
Forward Genetic Screens

AbstractGermline stem cells (GSCs) in Caenorhabditis elegans are maintained by GLP-1/Notch signaling from the niche and by a downstream RNA regulatory network. Loss of the GLP-1 receptor causes GSCs to precociously undergo meiotic differentiation, the “Glp” phenotype, due to a failure to self-renew. lst-1 and sygl-1 are functionally redundant direct targets of GLP-1 signaling whose gene products work with PUF RNA binding proteins to promote GSC self-renewal. Whereas single loss-of-function mutants are fertile, lst-1 sygl-1 double mutants are sterile and Glp. We set out to identify genes that function redundantly with either lst-1 or sygl-1 to maintain GSCs. To this end, we conducted forward genetic screens for Glp mutants in genetic backgrounds lacking functional copies of either lst-1 or sygl-1. The screens generated nine glp-1 alleles, two lst-1 alleles, and one allele of pole-1, which encodes the catalytic subunit of DNA polymerase ε. Three glp-1 alleles reside in Ankyrin (ANK) repeats not previously mutated. pole-1 single mutants have a low penetrance Glp that is enhanced by loss of either lst-1 or sygl-1. Thus, the screen uncovered one locus that interacts genetically with both lst-1 and sygl-1 and generated useful mutations for further studies of GSC regulation.

scholarly journals Dendrites with specialized glial attachments develop by retrograde extension using SAX-7 and GRDN-1

2019 ◽  
Author(s):  
Elizabeth R. Cebul ◽  
Ian G. McLachlan ◽  
Maxwell G. Heiman
Keyword(s):  
Glial Cell ◽  
Molecular Mechanism ◽  
Mammalian Brain ◽  
Cytoplasmic Protein ◽  
Genetic Screens ◽  
Sense Organs ◽  
Adhesion Protein ◽  
C Elegans ◽  
Dendrite Development ◽  
Forward Genetic Screens

ABSTRACTDendrites develop elaborate morphologies in concert with surrounding glia, but the molecules that coordinate dendrite and glial morphogenesis are mostly unknown.C. elegansoffers a powerful model for identifying such factors. Previous work in this system examined dendrites and glia that develop within epithelia, similar to mammalian sense organs. Here, we focus on the neurons BAG and URX, which are not part of an epithelium but instead form membranous attachments to a single glial cell at the nose, reminiscent of dendrite-glia contacts in the mammalian brain. We show that these dendrites develop by retrograde extension, in which the nascent dendrite endings anchor to the presumptive nose and then extend by stretch during embryo elongation. Using forward genetic screens, we find that dendrite development requires the adhesion protein SAX-7/L1CAM and the cytoplasmic protein GRDN-1/CCDC88C to anchor dendrite endings at the nose. SAX-7 acts in neurons and glia, while GRDN-1 acts in glia to non-autonomously promote dendrite extension. Thus, this work shows how glial factors can help to shape dendrites, and identifies a novel molecular mechanism for dendrite growth by retrograde extension.

scholarly journals Stem Cells: Muscle Cells Enwrap Escaped Germline Stem Cells in C. elegans

2019 ◽  
Vol 29 (5) ◽  
pp. R150-R152
Author(s):  
Charlotte A. Kelley ◽  
Erin J. Cram
Keyword(s):  
Stem Cells ◽  
Muscle Cells ◽  
Germline Stem Cells ◽  
C Elegans

scholarly journals Regulation of the mitosis/meiosis decision in the Caenorhabditis elegans germline

2003 ◽  
Vol 358 (1436) ◽  
pp. 1359-1362 ◽  
Author(s):  
Sarah L. Crittenden ◽  
Christian R. Eckmann ◽  
Liaoteng Wang ◽  
David S. Bernstein ◽  
Marvin Wickens ◽  
...  
Keyword(s):  
Stem Cells ◽  
Caenorhabditis Elegans ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Germline Stem Cells ◽  
Puf Proteins ◽  
C Elegans ◽  
Transcriptional Regulatory ◽  
Mitotic Proliferation ◽  
Multicellular Organisms

During the development of multicellular organisms, the processes of growth and differentiation are kept in balance to generate and maintain tissues and organs of the correct size, shape and cellular composition. We have investigated the molecular controls of growth and differentiation in the Caenorhabditis elegans germline. A single somatic cell, called the distal tip cell, promotes mitotic proliferation in the adjacent germline by GLP–1/Notch signalling. Within the germline, the decisions between mitosis and meiosis and between spermatogenesis and oogenesis are controlled by a group of conserved RNA regulators. FBF, a member of the PUF (for Pumilio and FBF) family of RNA–binding proteins, promotes mitosis by repressing gld–1 mRNA activity; the GLD–1, GLD–2, GLD–3 and NOS–3 proteins promote entry into meiosis by regulating mRNAs that remain unknown. The regulatory balance between opposing FBF and GLD activities is crucial for controlling the extent of germline proliferation. PUF proteins regulate germline stem cells in both Drosophila and C. elegans and are localized to germline stem cells of the mammalian testis. Therefore, this post–transcriptional regulatory switch may be an ancient mechanism for controlling maintenance of stem cells versus differentiation.

scholarly journals Applications of piggyBac Transposons for Genome Manipulation in Stem Cells

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yi Sun ◽  
Guang Liu ◽  
Yue Huang
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Stem Cell Research ◽  
Recent Progress ◽  
Genetic Screens ◽  
Gene Therapy Vector ◽  
The Past ◽  
Forward Genetic Screens ◽  
Basic Biology ◽  
Genome Manipulation

Transposons are mobile genetic elements in the genome. The piggyBac (PB) transposon system is increasingly being used for stem cell research due to its high transposition efficiency and seamless excision capacity. Over the past few decades, forward genetic screens based on PB transposons have been successfully established to identify genes associated with drug resistance and stem cell-related characteristics. Moreover, PB transposon is regarded as a promising gene therapy vector and has been used in some clinically relevant stem cells. Here, we review the recent progress on the basic biology of PB, highlight its applications in current stem cell research, and discuss its advantages and challenges.

scholarly journals Identification of a new allele of O-fucosyltransferase 1 involved in Drosophila intestinal stem cell regulation

Biology Open ◽  
2021 ◽  
Vol 10 (11) ◽  
Author(s):  
Lin Shi ◽  
Ruiyan Kong ◽  
Zhengran Li ◽  
Hang Zhao ◽  
Rui Ma ◽  
...  
Keyword(s):  
Stem Cells ◽  
Adult Stem Cells ◽  
Notch Signaling Pathway ◽  
Notch Receptor ◽  
P Element ◽  
Intestinal Stem Cells ◽  
Genetic Screens ◽  
Stem Cell Regulation ◽  
Proliferation And Differentiation ◽  
Forward Genetic Screens

ABSTRACT Adult stem cells are critical for the maintenance of tissue homeostasis. However, how the proliferation and differentiation of intestinal stem cells (ISCs) are regulated remains not fully understood. Here, we find a mutant, stum 9-3, affecting the proliferation and differentiation of Drosophila adult ISCs in a forward genetic screen for factors regulating the proliferation and differentiation ISCs. stum 9-3 acts through the conserved Notch signaling pathway, upstream of the S2 cleavage of the Notch receptor. Interestingly, the phenotype of stum 9-3 mutant is not caused by disruption of stumble (stum), where the p-element is inserted. Detailed mapping, rescue experiments and mutant characterization show that stum 9-3 is a new allele of O-fucosyltransferase 1 (O-fut1). Our results indicate that unexpected mutants with interesting phenotype could be recovered in forward genetic screens using known p-element insertion stocks.

scholarly journals Systemic regulation of mitochondria by germline proteostasis prevents protein aggregation in the soma of C. elegans

2021 ◽  
Vol 7 (26) ◽  
pp. eabg3012
Author(s):  
Giuseppe Calculli ◽  
Hyun Ju Lee ◽  
Koning Shen ◽  
Uyen Pham ◽  
Marija Herholz ◽  
...  
Keyword(s):  
Stem Cells ◽  
Protein Aggregation ◽  
Germ Line ◽  
Wnt Signaling Pathway ◽  
Germline Stem Cells ◽  
C Elegans ◽  
Unfolded Protein ◽  
Somatic Tissues ◽  
Intracellular Changes ◽  
The Unfolded Protein Response

Protein aggregation causes intracellular changes in neurons, which elicit signals to modulate proteostasis in the periphery. Beyond the nervous system, a fundamental question is whether other organs also communicate their proteostasis status to distal tissues. Here, we examine whether proteostasis of the germ line influences somatic tissues. To this end, we induce aggregation of germline-specific PGL-1 protein in germline stem cells of Caenorhabditis elegans. Besides altering the intracellular mitochondrial network of germline cells, PGL-1 aggregation also reduces the mitochondrial content of somatic tissues through long-range Wnt signaling pathway. This process induces the unfolded protein response of the mitochondria in the soma, promoting somatic mitochondrial fragmentation and aggregation of proteins linked with neurodegenerative diseases such as Huntington’s and amyotrophic lateral sclerosis. Thus, the proteostasis status of germline stem cells coordinates mitochondrial networks and protein aggregation through the organism.

scholarly journals C. elegans germ cells divide and differentiate along a folded epithelium

2018 ◽  
Author(s):  
Hannah S. Seidel ◽  
Tilmira A. Smith ◽  
Jessica K. Evans ◽  
Jarred Q. Stamper ◽  
Thomas G. Mast ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Germ Cells ◽  
Cell Model ◽  
Three Dimensional ◽  
3D Models ◽  
Germline Stem Cells ◽  
C Elegans ◽  
Stem Cell Regulation ◽  
Stem Cell Model

AbstractKnowing how stem cells and their progeny are positioned within their tissues is essential for understanding their regulation. One paradigm for stem cell regulation is the C. elegans germline, which is maintained by a pool of germline stem cells in the distal gonad, in a region known as the ‘progenitor zone’. The C. elegans germline is widely used as a stem cell model, but the cellular architecture of the progenitor zone has been unclear. Here we characterize this architecture by creating virtual 3D models of the progenitor zone in both sexes. We show that the progenitor zone in adult hermaphrodites is essentially a folded epithelium. The progenitor zone in males is not folded. Analysis of germ cell division shows that daughter cells are born side-by-side along the surface of the epithelium. Analysis of a key regulator driving differentiation, GLD-1, shows that germ cells in hermaphrodites differentiate along the path of the folded epithelium, with previously described “steps” in GLD-1 expression corresponding to germline folds. Our study provides a three-dimensional view of how C. elegans germ cells progress from stem cell to overt differentiation, with critical implications for regulators driving this transition.

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