Stage-specific accumulation of the terminal differentiation factor LIN-29 during Caenorhabditis elegans development

Development ◽  
1996 ◽  
Vol 122 (8) ◽  
pp. 2517-2527 ◽  
Author(s):  
J.C. Bettinger ◽  
K. Lee ◽  
A.E. Rougvie
Keyword(s):  
Caenorhabditis Elegans ◽  
Larval Stage ◽  
Terminal Differentiation ◽  
Loss Of Function ◽  
Cell Nuclei ◽  
Zinc Finger Transcription Factor ◽  
Gene Pathway ◽  
Seam Cell ◽  
Specific Accumulation ◽  
Heterochronic Gene

The Caenorhabditis elegans gene lin-29 is required for the terminal differentiation of the lateral hypodermal seam cells during the larval-to-adult molt. We find that lin-29 protein accumulates in the nuclei of these cells, consistent with its predicted role as a zinc finger transcription factor. The earliest detectable LIN-29 accumulation in seam cell nuclei is during the last larval stage (L4), following the final seam cell division, which occurs during the L3-to-L4 molt. LIN-29 accumulates in all hypodermal nuclei during the L4 stage. The time of LIN-29 appearance in the hypodermis is controlled by the heterochronic gene pathway: LIN-29 accumulates in the hypodermis abnormally early, during the third larval stage, in loss-of-function lin-14, lin-28 and lin-42 mutants, and fails to accumulate in hypodermis of lin-4 mutants. LIN-29 also accumulates stage-specifically in the nuclei of a variety of non-hypodermal cells during development. Its accumulation is dependent upon the upstream heterochronic genes in some, but not all, of these non-hypodermal cells.

scholarly journals Identification of Heterochronic Mutants in Caenorhabditis elegans: Temporal Misexpression of a Collagen::Green Fluorescent Protein Fusion Gene

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1335-1351
Author(s):  
Juan E Abrahante ◽  
Eric A Miller ◽  
Ann E Rougvie
Keyword(s):  
Green Fluorescent Protein ◽  
Caenorhabditis Elegans ◽  
Fluorescent Protein ◽  
Fusion Gene ◽  
Terminal Differentiation ◽  
Protein Fusion ◽  
Gene Pathway ◽  
Seam Cell ◽  
Heterochronic Gene ◽  
Green Fluorescent

Abstract The heterochronic genes lin-4, lin-14, lin-28, and lin-29 specify the timing of lateral hypodermal seam cell terminal differentiation in Caenorhabditis elegans. We devised a screen to identify additional genes involved in this developmental timing mechanism based on identification of mutants that exhibit temporal misexpression from the col-19 promoter, a downstream target of the heterochronic gene pathway. We fused the col-19 promoter to the green fluorescent protein gene (gfp) and demonstrated that hypodermal expression of the fusion gene is adult-specific in wild-type animals and temporally regulated by the heterochronic gene pathway. We generated a transgenic strain in which the col-19::gfp fusion construct is not expressed because of mutation of lin-4, which prevents seam cell terminal differentiation. We have identified and characterized 26 mutations that restore col-19::gfp expression in the lin-4 mutant background. Most of the mutations also restore other aspects of the seam cell terminal differentiation program that are defective in lin-4 mutant animals. Twelve mutations are alleles of three previously identified genes known to be required for proper timing of hypodermal terminal differentiation. Among these are four new alleles of lin-42, a heterochronic gene for which a single allele had been described previously. Two mutations define a new gene, lin-58. When separated from lin-4, the lin-58 mutations cause precocious seam cell terminal differentiation and thus define a new member of the heterochronic gene pathway.

The Caenorhabditis elegans heterochronic gene pathway controls stage-specific transcription of collagen genes

Development ◽  
1995 ◽  
Vol 121 (8) ◽  
pp. 2471-2478 ◽  
Author(s):  
Z. Liu ◽  
S. Kirch ◽  
V. Ambros
Keyword(s):  
Caenorhabditis Elegans ◽  
Regulatory Gene ◽  
Terminal Differentiation ◽  
Northern Analysis ◽  
Specific Gene ◽  
Mrna Levels ◽  
Lacz Reporter ◽  
Gene Pathway ◽  
Heterochronic Gene ◽  
Collagen Genes

In Caenorhabditis elegans, the terminal differentiation of the hypodermal cells occurs at the larval-to-adult molt, and is characterized in part by the formation of a morphologically distinct adult cuticle. The timing of this event is controlled by a pathway of heterochronic genes that includes the relatively direct regulatory gene, lin-29, and upstream genes lin-4, lin-14 and lin-28. Using northern analysis to detect endogenous collagen mRNA levels and collagen/lacZ reporter constructs to monitor collagen transcriptional activity, we show that the stage-specific switch from larval cuticle to adult cuticle correlates with the transcriptional activation of adult-specific collagen genes and repression of larval-specific collagen genes. Heterochronic mutations that cause precocious formation of adult cuticle also cause precocious transcription of the adult-specific collagen genes, col-7 and col-19; heterochronic mutations that prevent the switch to adult cuticle cause continued expression of the larval collagen gene, col-17, in adults and prevent adult-specific activation of col-7 or col-19. A 235 bp segment of col-19 5′ sequences is sufficient to direct the adult-specific expression of a col-19/lacZ reporter gene in hypodermal cells. These findings indicate that the heterochronic gene pathway regulates the timing of hypodermal cell terminal differentiation by regulating larval- and adult-specific gene expression, perhaps by the direct action of lin-29.

The terminal differentiation factor LIN-29 is required for proper vulval morphogenesis and egg laying in Caenorhabditis elegans

Development ◽  
1997 ◽  
Vol 124 (21) ◽  
pp. 4333-4342 ◽  
Author(s):  
J.C. Bettinger ◽  
S. Euling ◽  
A.E. Rougvie
Keyword(s):  
Caenorhabditis Elegans ◽  
Terminal Differentiation ◽  
Egg Laying ◽  
Small Subset ◽  
Wild Type ◽  
Vulval Development ◽  
Genetic Mosaics ◽  
Hypodermal Cell ◽  
Heterochronic Gene ◽  
Final Molt

Caenorhabditis elegans vulval development culminates during exit from the L4-to-adult molt with the formation of an opening through the adult hypodermis and cuticle that is used for egg laying and mating. Vulva formation requires the heterochronic gene lin-29, which triggers hypodermal cell terminal differentiation during the final molt. lin-29 mutants are unable to lay eggs or mate because no vulval opening forms; instead, a protrusion forms at the site of the vulva. We demonstrate through analysis of genetic mosaics that lin-29 is absolutely required in a small subset of lateral hypodermal seam cells, adjacent to the vulva, for wild-type vulva formation and egg laying. However, lin-29 function is not strictly limited to the lateral hypodermis. First, LIN-29 accumulates in many non-hypodermal cells with known roles in vulva formation or egg laying. Second, animals homozygous for one lin-29 allele, ga94, have the vulval defect and cannot lay eggs, despite having a terminally differentiated adult lateral hypodermis. Finally, vulval morphogenesis and egg laying requires lin-29 activity within the EMS lineage, a lineage that does not generate hypodermal cells.

scholarly journals Untwisting the Caenorhabditis elegans embryo

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Ryan Patrick Christensen ◽  
Alexandra Bokinsky ◽  
Anthony Santella ◽  
Yicong Wu ◽  
Javier Marquina-Solis ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Tracking ◽  
Positional Information ◽  
Supplementary File ◽  
Cell Nuclei ◽  
C Elegans ◽  
Seam Cell ◽  
Late Embryogenesis ◽  
Embryonic Nervous System ◽  
Supplementary Material

The nematode Caenorhabditis elegans possesses a simple embryonic nervous system with few enough neurons that the growth of each cell could be followed to provide a systems-level view of development. However, studies of single cell development have largely been conducted in fixed or pre-twitching live embryos, because of technical difficulties associated with embryo movement in late embryogenesis. We present open-source untwisting and annotation software (http://mipav.cit.nih.gov/plugin_jws/mipav_worm_plugin.php) that allows the investigation of neurodevelopmental events in late embryogenesis and apply it to track the 3D positions of seam cell nuclei, neurons, and neurites in multiple elongating embryos. We also provide a tutorial describing how to use the software (<xref ref-type="supplementary-material" rid="SD1-data">Supplementary file 1</xref>) and a detailed description of the untwisting algorithm (Appendix). The detailed positional information we obtained enabled us to develop a composite model showing movement of these cells and neurites in an 'average' worm embryo. The untwisting and cell tracking capabilities of our method provide a foundation on which to catalog C. elegans neurodevelopment, allowing interrogation of developmental events in previously inaccessible periods of embryogenesis.

scholarly journals Isoform-Specific Mutations in the Caenorhabditis elegans Heterochronic Gene lin-14 Affect Stage-Specific Patterning

Genetics ◽  
2001 ◽  
Vol 157 (1) ◽  
pp. 199-209 ◽  
Author(s):  
Brenda J Reinhart ◽  
Gary Ruvkun
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Fate ◽  
Larval Stage ◽  
Protein Isoforms ◽  
Specific Cell ◽  
Temporal Expression ◽  
Critical Determinant ◽  
Temporal Gradient ◽  
Protein Levels ◽  
Heterochronic Gene

Abstract The Caenorhabditis elegans heterochronic gene lin-14 specifies the temporal sequence of postembryonic developmental events. lin-14, which encodes differentially spliced LIN-14A and LIN-14B1/B2 protein isoforms, acts at distinct times during the first larval stage to specify first and second larval stage-specific cell lineages. Proposed models for the molecular basis of these two lin-14 gene activities have included the production of functionally distinct isoforms and the generation of a temporal gradient of LIN-14 protein. We report here that loss of the LIN-14B1/B2 isoforms alone affects one of the two lin-14 temporal patterning functions, the specification of second larval stage lineages. A temporal expression difference between LIN-14A and LIN-14B1/B2 is not responsible for the stage-specific phenotype: protein levels of all LIN-14 isoforms are high in early first larval stage animals and decrease during the first larval stage. However, LIN-14A can partially substitute for LIN-14B1/B2 when expressed at a higher-than-normal level in the late L1 stage. These data indicate that LIN-14B1/B2 isoforms do not provide a distinct function of the lin-14 locus in developmental timing but rather may contribute to an overall level of LIN-14 protein that is the critical determinant of temporal cell fate.

The heterochronic gene lin-29 encodes a zinc finger protein that controls a terminal differentiation event in Caenorhabditis elegans

Development ◽  
1995 ◽  
Vol 121 (8) ◽  
pp. 2491-2500 ◽  
Author(s):  
A.E. Rougvie ◽  
V. Ambros
Keyword(s):  
Caenorhabditis Elegans ◽  
Zinc Finger Protein ◽  
Terminal Differentiation ◽  
Regulatory Sequences ◽  
Larval Stages ◽  
Heterochronic Gene ◽  
Final Molt ◽  
Differentiation Event

A hierarchy of heterochronic genes, lin-4, lin-14, lin-28 and lin-29, temporally restricts terminal differentiation of Caenorhabditis elegans hypodermal seam cells to the final molt. This terminal differentiation event involves cell cycle exit, cell fusion and the differential regulation of genes expressed in the larval versus adult hypodermis. lin-29 is the most downstream gene in the developmental timing pathway and thus it is the most direct known regulator of these diverse processes. We show that lin-29 encodes a protein with five zinc fingers of the (Cys)2-(His)2 class and thus likely controls these processes by regulating transcription in a stage-specific manner. Consistent with this role, a lin-29 fusion protein binds in vitro to the 5′ regulatory sequences necessary in vivo for expression of col-19, a collagen gene expressed in the adult hypodermis. lin-29 mRNA is detected in the first larval stage and increases in abundance through subsequent larval stages until the final molt, when lin-29 activity is required for terminal differentiation.

scholarly journals A novel function for the Caenorhabditis elegans torsin OOC-5 in nucleoporin localization and nuclear import

2015 ◽  
Vol 26 (9) ◽  
pp. 1752-1763 ◽  
Author(s):  
Michael J. W. VanGompel ◽  
Ken C. Q. Nguyen ◽  
David H. Hall ◽  
William T. Dauer ◽  
Lesilee S. Rose
Keyword(s):  
Caenorhabditis Elegans ◽  
Germ Cell ◽  
Nuclear Import ◽  
Size Exclusion ◽  
Nuclear Pore ◽  
Loss Of Function ◽  
Cell Nuclei ◽  
Dyt1 Dystonia ◽  
Pore Size Exclusion ◽  
And Function

Torsin proteins are AAA+ ATPases that localize to the endoplasmic reticular/nuclear envelope (ER/NE) lumen. A mutation that markedly impairs torsinA function causes the CNS disorder DYT1 dystonia. Abnormalities of NE membranes have been linked to torsinA loss of function and the pathogenesis of DYT1 dystonia, leading us to investigate the role of the Caenorhabditis elegans torsinA homologue OOC-5 at the NE. We report a novel role for torsin in nuclear pore biology. In ooc-5–mutant germ cell nuclei, nucleoporins (Nups) were mislocalized in large plaques beginning at meiotic entry and persisted throughout meiosis. Moreover, the KASH protein ZYG-12 was mislocalized in ooc-5 gonads. Nups were mislocalized in adult intestinal nuclei and in embryos from mutant mothers. EM analysis revealed vesicle-like structures in the perinuclear space of intestinal and germ cell nuclei, similar to defects reported in torsin-mutant flies and mice. Consistent with a functional disruption of Nups, ooc-5–mutant embryos displayed impaired nuclear import kinetics, although the nuclear pore-size exclusion barrier was maintained. Our data are the first to demonstrate a requirement for a torsin for normal Nup localization and function and suggest that these functions are likely conserved.

gon-2, a Gene Required for Gonadogenesis in Caenorhabditis elegans

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1077-1089 ◽  
Author(s):  
Andrew Y Sun ◽  
Eric J Lambie
Keyword(s):  
Caenorhabditis Elegans ◽  
Larval Stage ◽  
Cell Lineage ◽  
Temperature Sensitive ◽  
Loss Of Function ◽  
Primary Defect ◽  
Cell Fates ◽  
Fourth Larval Stage ◽  
Full Complement ◽  
Sensitive Allele

The gonad of the Caenorhabditis elegans hermaphrodite is generated by the postembryonic divisions of two somatic precursors, Z1 and Z4, and two germline precursors, Z2 and Z3. These cells begin division midway through the first larval stage. By the end of the fourth larval stage, Z1 and Z4 produce 143 descendants, while Z2 and Z3 give rise to ∼1000 descendants. The divisions of Z2 and Z3 are dependent on signals produced by Z1 and Z4, but not vice versa. We have characterized the properties of five loss-of-function alleles of a newly described gene, which we call gon-2. In gon-2 mutants, gonadogenesis is severely impaired; in some animals, none of the gonad progenitors undergo any postembryonic divisions. Mutations in gon-2 have a partial maternal effect: either maternal or zygotic expression is sufficient to prevent the severe gonadogenesis defects. By cell lineage analysis, we found that the primary defect in gon-2 mutants is a delay (sometimes a complete block) in the onset and continuation of gonadal divisions. The results of upshift experiments using a temperature-sensitive allele suggest that zygotic expression of gon-2 begins early in embryogenesis, before the birth of Z1 and Z4. The results of downshift experiments suggest that Z1 and Z4 can generate the full complement of gonadal tissues even when gon-2 function is inhibited until the end of the second larval stage. Thus, gon-2 activity is probably not required for the specification of gonadal cell fates, but appears to be generally required for gonadal cell divisions.

par-4, a gene required for cytoplasmic localization and determination of specific cell types in Caenorhabditis elegans embryogenesis.

Genetics ◽  
1992 ◽  
Vol 130 (4) ◽  
pp. 771-790 ◽  
Author(s):  
D G Morton ◽  
J M Roos ◽  
K J Kemphues
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Types ◽  
Intestinal Cells ◽  
Specific Cell ◽  
Cytoplasmic Localization ◽  
Loss Of Function ◽  
Embryo Viability ◽  
Cell Stage ◽  
Maternal Genome

Abstract Specification of some cell fates in the early Caenorhabditis elegans embryo is mediated by cytoplasmic localization under control of the maternal genome. Using nine newly isolated mutations, and two existing mutations, we have analyzed the role of the maternally expressed gene par-4 in cytoplasmic localization. We recovered seven new par-4 alleles in screens for maternal effect lethal mutations that result in failure to differentiate intestinal cells. Two additional par-4 mutations were identified in noncomplementation screens using strains with a high frequency of transposon mobility. All 11 mutations cause defects early in development of embryos produced by homozygous mutant mothers. Analysis with a deficiency in the region indicates that it33 is a strong loss-of-function mutation. par-4(it33) terminal stage embryos contain many cells, but show no morphogenesis, and are lacking intestinal cells. Temperature shifts with the it57ts allele suggest that the critical period for both intestinal differentiation and embryo viability begins during oogenesis, about 1.5 hr before fertilization, and ends before the four-cell stage. We propose that the primary function of the par-4 gene is to act as part of a maternally encoded system for cytoplasmic localization in the first cell cycle, with par-4 playing a particularly important role in the determination of intestine. Analysis of a par-4; par-2 double mutant suggests that par-4 and par-2 gene products interact in this system.

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