Tubes and the single C. elegans excretory cell

2002 ◽  
Vol 12 (10) ◽  
pp. 479-484 ◽  
Author(s):  
M Buechner
Keyword(s):  
C Elegans ◽  
Excretory Cell

Regulation of ectodermal and excretory function by the C. elegans POU homeobox gene ceh-6

Development ◽  
2001 ◽  
Vol 128 (5) ◽  
pp. 779-790 ◽  
Author(s):  
T.R. Burglin ◽  
G. Ruvkun
Keyword(s):  
Transcription Factor ◽  
Epithelial Cells ◽  
Homeobox Genes ◽  
Homeobox Gene ◽  
Null Mutant ◽  
Reporter Construct ◽  
Excretory Function ◽  
C Elegans ◽  
Gfp Reporter ◽  
Excretory Cell

Caenorhabditis elegans has three POU homeobox genes, unc-86, ceh-6 and ceh-18. ceh-6 is the ortholog of vertebrate Brn1, Brn2, SCIP/Oct6 and Brn4 and fly Cf1a/drifter/ventral veinless. Comparison of C. elegans and C. briggsae CEH-6 shows that it is highly conserved. C. elegans has only three POU homeobox genes, while Drosophila has five that fall into four families. Immunofluorescent detection of the CEH-6 protein reveals that it is expressed in particular head and ventral cord neurons, as well as in rectal epithelial cells, and in the excretory cell, which is required for osmoregulation. A deletion of the ceh-6 locus causes 80% embryonic lethality. During morphogenesis, embryos extrude cells in the rectal region of the tail or rupture, indicative of a defect in the rectal epithelial cells that express ceh-6. Those embryos that hatch are sick and develop vacuoles, a phenotype similar to that caused by laser ablation of the excretory cell. A GFP reporter construct expressed in the excretory cell reveals inappropriate canal structures in the ceh-6 null mutant. Members of the POU-III family are expressed in tissues involved in osmoregulation and secretion in a number of species. We propose that one evolutionary conserved function of the POU-III transcription factor class could be the regulation of genes that mediate secretion/osmoregulation.

scholarly journals A polarity pathway for exocyst-dependent intracellular tube extension

2020 ◽  
Author(s):  
Joshua Abrams ◽  
Jeremy Nance
Keyword(s):  
Mammalian Cells ◽  
Rho Gtpase ◽  
Tube Formation ◽  
Membrane Domain ◽  
Lumen Formation ◽  
Vesicle Tethering ◽  
C Elegans ◽  
And Function ◽  
Excretory Cell ◽  
Upstream Regulators

ABSTRACTLumen extension in intracellular tubes can occur by the directed fusion of vesicles with an invading apical membrane domain. Within the C. elegans excretory cell, which contains an intracellular tube, the exocyst vesicle-tethering complex is enriched at the lumenal membrane domain and is required for tube formation, suggesting that it targets vesicles needed for lumen extension. Here, we identify a polarity pathway that promotes intracellular tube formation by enriching the exocyst at the lumenal membrane. We show that the PAR polarity proteins PAR-6 and PKC-3/aPKC localize to the lumenal membrane domain and function within the excretory cell to promote lumen extension, similar to exocyst component SEC-5 and exocyst regulator RAL-1. Using acute protein depletion, we find that PAR-6 is required to recruit the exocyst to the lumenal membrane domain, whereas PAR-3, which functions as an exocyst receptor in mammalian cells, appears to be dispensable for exocyst localization and lumen extension. Finally, we show that the Rho GTPase CDC-42 and the RhoGEF EXC-5/FGD act as upstream regulators of lumen formation by recruiting PAR-6 and PKC-3 to the lumenal membrane. Our findings reveal a molecular pathway that connects Rho GTPase signaling, cell polarity, and vesicle-tethering proteins to promote lumen extension in intracellular tubes.

scholarly journals Transcriptional Regulation of AQP-8, a Caenorhabditis elegans Aquaporin Exclusively Expressed in the Excretory System, by the POU Homeobox Transcription Factor CEH-6

2007 ◽  
Vol 282 (38) ◽  
pp. 28074-28086 ◽  
Author(s):  
Allan K. Mah ◽  
Kristin R. Armstrong ◽  
Derek S. Chew ◽  
Jeffrey S. Chu ◽  
Domena K. Tu ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Regulatory Networks ◽  
Regulatory Region ◽  
Regulatory Elements ◽  
Upstream Sequence ◽  
Consensus Binding Site ◽  
Mobility Shift ◽  
C Elegans ◽  
Octamer Motif ◽  
Excretory Cell

Due to the ever changing environmental conditions in soil, regulation of osmotic homeostasis in the soil-dwelling nematode Caenorhabditis elegans is critical. AQP-8 is a C. elegans aquaporin that is expressed in the excretory cell, a renal equivalent tissue, where the protein participates in maintaining water balance. To better understand the regulation of AQP-8, we undertook a promoter analysis to identify the aqp-8 cis-regulatory elements. Using progressive 5′ deletions of upstream sequence, we have mapped an essential regulatory region to roughly 300 bp upstream of the translational start site of aqp-8. Analysis of this region revealed a sequence corresponding to a known DNA functional element (octamer motif), which interacts with POU homeobox transcription factors. Phylogenetic footprinting showed that this site is perfectly conserved in four nematode species. The octamer site's function was further confirmed by deletion analyses, mutagenesis, functional studies, and electrophoretic mobility shift assays. Of the three POU homeobox proteins encoded in the C. elegans genome, CEH-6 is the only member that is expressed in the excretory cell. We show that expression of AQP-8 is regulated by CEH-6 by performing RNA interference experiments. CEH-6's mammalian ortholog, Brn1, is expressed both in the kidney and the central nervous system and binds to the same octamer consensus binding site to drive gene expression. These parallels in transcriptional control between Brn1 and CEH-6 suggest that C. elegans may well be an appropriate model for determining gene-regulatory networks in the developing vertebrate kidney.

sma-1 encodes a betaH-spectrin homolog required for Caenorhabditis elegans morphogenesis

Development ◽  
1998 ◽  
Vol 125 (11) ◽  
pp. 2087-2098 ◽  
Author(s):  
C. McKeown ◽  
V. Praitis ◽  
J. Austin
Keyword(s):  
Plasma Membrane ◽  
Caenorhabditis Elegans ◽  
Apical Membrane ◽  
Membrane Skeleton ◽  
Elongation Rate ◽  
Apical Plasma Membrane ◽  
Wild Type ◽  
C Elegans ◽  
Lateral Membrane ◽  
Excretory Cell

Morphogenesis transforms the C. elegans embryo from a ball of cells into a vermiform larva. During this transformation, the embryo increases fourfold in length; present data indicates this elongation results from contraction of the epidermal actin cytoskeleton. In sma-1 mutants, the extent of embryonic elongation is decreased and the resulting sma-1 larvae, although viable, are shorter than normal. We find that sma-1 mutants elongate for the same length of time as wild-type embryos, but at a decreased rate. The sma-1 mutants we have isolated vary in phenotypic severity, with the most severe alleles showing the greatest decrease in elongation rate. The sma-1 gene encodes a homolog of betaH-spectrin, a novel beta-spectrin isoform first identified in Drosophila. sma-1 RNA is expressed in epithelial tissues in the C. elegans embryo: in the embryonic epidermis at the start of morphogenesis and subsequently in the developing pharynx, intestine and excretory cell. In Drosophila, betaH-spectrin associates with the apical plasma membrane of epithelial cells; beta-spectrin is found at the lateral membrane. We propose that SMA-1 is a component of an apical membrane skeleton in the C. elegans embryonic epidermis that determines the rate of elongation during morphogenesis.

The glycomes of Caenorhabditis elegans and other model organisms

2002 ◽  
Vol 69 ◽  
pp. 117-134 ◽  
Author(s):  
Stuart M. Haslam ◽  
David Gems ◽  
Howard R. Morris ◽  
Anne Dell
Keyword(s):  
Caenorhabditis Elegans ◽  
Current Knowledge ◽  
Structural Data ◽  
Model Organisms ◽  
Entire Genome ◽  
C Elegans ◽  
The Face ◽  
Area Of Concern ◽  
Nematode Worm

There is no doubt that the immense amount of information that is being generated by the initial sequencing and secondary interrogation of various genomes will change the face of glycobiological research. However, a major area of concern is that detailed structural knowledge of the ultimate products of genes that are identified as being involved in glycoconjugate biosynthesis is still limited. This is illustrated clearly by the nematode worm Caenorhabditis elegans, which was the first multicellular organism to have its entire genome sequenced. To date, only limited structural data on the glycosylated molecules of this organism have been reported. Our laboratory is addressing this problem by performing detailed MS structural characterization of the N-linked glycans of C. elegans; high-mannose structures dominate, with only minor amounts of complex-type structures. Novel, highly fucosylated truncated structures are also present which are difucosylated on the proximal N-acetylglucosamine of the chitobiose core as well as containing unusual Fucα1–2Gal1–2Man as peripheral structures. The implications of these results in terms of the identification of ligands for genomically predicted lectins and potential glycosyltransferases are discussed in this chapter. Current knowledge on the glycomes of other model organisms such as Dictyostelium discoideum, Saccharomyces cerevisiae and Drosophila melanogaster is also discussed briefly.

How do histone modifications contribute to transgenerational epigenetic inheritance in C. elegans?

2020 ◽  
Vol 48 (3) ◽  
pp. 1019-1034 ◽  
Author(s):  
Rachel M. Woodhouse ◽  
Alyson Ashe
Keyword(s):  
Histone Modifications ◽  
Molecular Mechanisms ◽  
Epigenetic Inheritance ◽  
Nematode Caenorhabditis Elegans ◽  
Histone Methyltransferases ◽  
Transgenerational Epigenetic Inheritance ◽  
C Elegans ◽  
Recent Developments ◽  
Gene Regulatory

Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.

Centrosome Aurora A gradient ensures single polarity axis in C. elegans embryos

2020 ◽  
Vol 48 (3) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sukriti Kapoor ◽  
Sachin Kotak
Keyword(s):  
Symmetry Breaking ◽  
Cell Fate ◽  
Cell Cortex ◽  
Axis Formation ◽  
Aurora A Kinase ◽  
Aurora A ◽  
C Elegans ◽  
Cell Embryo ◽  
Polarity Establishment

Cellular asymmetries are vital for generating cell fate diversity during development and in stem cells. In the newly fertilized Caenorhabditis elegans embryo, centrosomes are responsible for polarity establishment, i.e. anterior–posterior body axis formation. The signal for polarity originates from the centrosomes and is transmitted to the cell cortex, where it disassembles the actomyosin network. This event leads to symmetry breaking and the establishment of distinct domains of evolutionarily conserved PAR proteins. However, the identity of an essential component that localizes to the centrosomes and promotes symmetry breaking was unknown. Recent work has uncovered that the loss of Aurora A kinase (AIR-1 in C. elegans and hereafter referred to as Aurora A) in the one-cell embryo disrupts stereotypical actomyosin-based cortical flows that occur at the time of polarity establishment. This misregulation of actomyosin flow dynamics results in the occurrence of two polarity axes. Notably, the role of Aurora A in ensuring a single polarity axis is independent of its well-established function in centrosome maturation. The mechanism by which Aurora A directs symmetry breaking is likely through direct regulation of Rho-dependent contractility. In this mini-review, we will discuss the unconventional role of Aurora A kinase in polarity establishment in C. elegans embryos and propose a refined model of centrosome-dependent symmetry breaking.

Sign in / Sign up

Export Citation Format

Share Document