scholarly journals The lin-15 locus encodes two negative regulators of Caenorhabditis elegans vulval development.

1994 ◽  
Vol 5 (4) ◽  
pp. 395-411 ◽  
Author(s):  
L S Huang ◽  
P Tzou ◽  
P W Sternberg
Keyword(s):  
Caenorhabditis Elegans ◽  
Null Allele ◽  
Negative Regulator ◽  
Vulval Development ◽  
Genetic Studies ◽  
Vulval Precursor Cells ◽  
Complex Locus ◽  
Anchor Cell ◽  
Inductive Signal

During Caenorhabditis elegans vulval development, an inductive signal from the anchor cell stimulates three of the six vulval precursor cells (VPCs) to adopt vulval rather than nonvulval epidermal fates. Genes necessary for this induction include the lin-3 growth factor, the let-23 receptor tyrosine kinase, and let-60 ras. lin-15 is a negative regulator of this inductive pathway. In lin-15 mutant animals, all six VPCs adopt vulval fates, even in the absence of inductive signal. Previous genetic studies suggested that lin-15 is a complex locus with two independently mutable activities, A and B. We have cloned the lin-15 locus by germline transformation and find that it encodes two nonoverlapping transcripts that are transcribed in the same direction. The downstream transcript encodes the lin-15A function; the upstream transcript encodes the lin-15B function. The predicted lin-15A and lin-15B proteins are novel and hydrophilic. We have identified a molecular null allele of lin-15 and have used it to analyze the role of lin-15 in the signaling pathway. We find that lin-15 acts upstream of let-23 and in parallel to the inductive signal.

scholarly journals Cell fate patterning during C. elegans vulval development

Development ◽  
1993 ◽  
Vol 119 (Supplement) ◽  
pp. 9-18 ◽  
Author(s):  
Russell J. Hill ◽  
Paul W. Sternberg
Keyword(s):  
Cell Fate ◽  
Short Range ◽  
Precursor Cells ◽  
Cell Fates ◽  
Vulval Development ◽  
C Elegans ◽  
Vulval Precursor Cells ◽  
Combined Action ◽  
Anchor Cell ◽  
Inductive Signal

Precursor cells of the vulva of the C. elegans hermaphrodite choose between two vulval cell fates (1° and 2°) and a non-vulval epidermal fate (3°) in response to three intercellular signals. An inductive signal produced by the anchor cell induces the vulval precursors to assume the 1° and 2° vulval fates. This inductive signal is an EGF-like growth factor encoded by the gene lin-3. An inhibitory signal mediated by lin-15, and which may originate from the surrounding epidermis, prevents the vulval precursors from assuming vulval fates in the absence of the inductive signal. A short range lateral signal, which acts through the gene lin-12, regulates the pattern of 1° and 2° fates assumed by the induced vulval precursors. The combined action of the three signals precisely directs the six vulval precursors to adopt a 3° 3° 2° 1° 2 ° 3° pattern of fates. The amount of inductive signal produced by the anchor cell appears to determine the number or vulval precursors that assume vulval fates. The three induced vulval precursors most proximal to the anchor cell are proposed to adopt the 2° 1° 2° pattern of fates in response to a gradient of the inductive signal and also in response to lateral signalling that inhibits adjacent vulval precursor cells from both assuming the 1° fate.

Role of a raf proto-oncogene during Caenorhabditis elegans vulval development

1993 ◽  
Vol 340 (1293) ◽  
pp. 259-265 ◽  
Keyword(s):  
Caenorhabditis Elegans ◽  
Growth Factor ◽  
Tyrosine Kinase ◽  
Dominant Negative ◽  
Reverse Genetic ◽  
Vulval Development ◽  
Ras Protein ◽  
Family Protein ◽  
Inductive Signal

During Caenorhabditis elegans vulval induction, multipotent precursors respond to an inductive signal by generating vulval cells as opposed to non-specialized epiderm al cells. Both classical and ‘reverse’ genetic approaches have revealed that a cascade of nematode homologues of mammalian proto-oncogenes is necessary for induction of the vulva. The inductive signal is a growth factor encoded by the lin-3 gene and its candidate receptor is a tyrosine kinase encoded by the let-23 gene. let-23 acts via a Ras protein encoded by the let-60 gene. A nematode homologue of mammalian raf family protein serine/threonine kinases has been cloned and found to be encoded by the lin-45 gene. Dominant negative lin-45 raf mutants prevent vulval induction. A recessive lin-45 raf mutation prevents the excessive vulval differentiation caused by activated ras, indicating that raf might act downstream of ras during vulval induction.

Comparative developmental studies using Oscheius/Dolichorhabditis sp. CEW1 (Rhabditidae)

Nematology ◽  
2000 ◽  
Vol 2 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Marie Delattre ◽  
Marie-Laure Dichtel ◽  
Marie-Anne Félix
Keyword(s):  
Caenorhabditis Elegans ◽  
Genetic Analysis ◽  
Precursor Cells ◽  
Developmental Studies ◽  
Morphological Markers ◽  
Molecular Tools ◽  
Ras Gene ◽  
C Elegans ◽  
Vulval Precursor Cells ◽  
Anchor Cell

AbstractIn order to study the evolution of nematode vulva development, we focus on Oscheius/Dolichorhabditis sp. CEW1 (Rhabditidae) in comparison with Caenorhabditis elegans. In this species, the fates of the vulval precursor cells are determined by two successive nested inductions by the uterine anchor cell (instead of a single one in C. elegans). This hermaphroditic species can be cultured and handled like C. elegans. We review vulva development in this species. We present some molecular tools and the sequence of the Ras gene. This species is amenable to genetic analysis and we discuss the isolation of morphological markers. Afin d’étudier l’évolution du développement de la vulve des nématodes, nous nous concentrons sur l’espèce Oscheius/Dolichorhabditis sp. CEW1 (Rhabditidae) en la comparant à Caenorhabditis elegans. Dans cette espèce, les destinées des cellules précurseurs de la vulve sont déterminées par deux inductions emboîtées provenant de la cellule ancre de l’utérus (au lieu d’une seule chez C. elegans). Cette espèce hermaphrodite peut être élévée et manipulée comme C. elegans. Nous décrivons le développement de la vulve dans cette espèce. Nous présentons des outils moléculaires et la séquence du gène Ras. Les analyses génétiques sont possibles dans cette espèce et nous discutons l’isolement de marqueurs morphologiques.

scholarly journals Revealing the role of phospholipase Cβ3 in the regulation of VEGF-induced vascular permeability

Blood ◽  
2012 ◽  
Vol 120 (11) ◽  
pp. 2167-2173 ◽  
Author(s):  
Luke H. Hoeppner ◽  
Kathryn N. Phoenix ◽  
Karl J. Clark ◽  
Resham Bhattacharya ◽  
Xun Gong ◽  
...  
Keyword(s):  
Vascular Permeability ◽  
Real Time ◽  
Molecular Mechanisms ◽  
Negative Regulator ◽  
Transgenic Zebrafish ◽  
Genetic Studies ◽  
In Vivo Models ◽  
Ischemic Diseases

AbstractVEGF induces vascular permeability (VP) in ischemic diseases and cancer, leading to many pathophysiological consequences. The molecular mechanisms by which VEGF acts to induce hyperpermeability are poorly understood and in vivo models that easily facilitate real-time, genetic studies of VP do not exist. In the present study, we report a heat-inducible VEGF transgenic zebrafish (Danio rerio) model through which VP can be monitored in real time. Using this approach with morpholino-mediated gene knock-down and knockout mice, we describe a novel role of phospholipase Cβ3 as a negative regulator of VEGF-mediated VP by regulating intracellular Ca2+ release. Our results suggest an important effect of PLCβ3 on VP and provide a new model with which to identify genetic regulators of VP crucial to several disease processes.

scholarly journals The lin-11 LIM domain transcription factor is necessary for morphogenesis of C. elegans uterine cells

Development ◽  
1999 ◽  
Vol 126 (23) ◽  
pp. 5319-5326 ◽  
Author(s):  
A.P. Newman ◽  
G.Z. Acton ◽  
E. Hartwieg ◽  
H.R. Horvitz ◽  
P.W. Sternberg
Keyword(s):  
Transcription Factor ◽  
Caenorhabditis Elegans ◽  
Egg Laying ◽  
Wild Type ◽  
Lim Domain ◽  
C Elegans ◽  
Expression Studies ◽  
Vulval Precursor Cells ◽  
Cell Induction ◽  
Anchor Cell

The Caenorhabditis elegans hermaphrodite egg-laying system comprises several tissues, including the uterus and vulva. lin-11 encodes a LIM domain transcription factor needed for certain vulval precursor cells to divide asymmetrically. Based on lin-11 expression studies and the lin-11 mutant phenotype, we find that lin-11 is also required for C. elegans uterine morphogenesis. Specifically, lin-11 is expressed in the ventral uterine intermediate precursor (pi) cells and their progeny (the utse and uv1 cells), which connect the uterus to the vulva. Like (pi) cell induction, the uterine lin-11 expression responds to the uterine anchor cell and the lin-12-encoded receptor. In wild type animals, the utse, which forms the planar process at the uterine-vulval interface, fuses with the anchor cell. We found that, in lin-11 mutants, utse differentiation was abnormal, the utse failed to fuse with the anchor cell and a functional uterine-vulval connection was not made. These findings indicate that lin-11 is essential for uterine-vulval morphogenesis.

scholarly journals Insulated Switches: Dual-Function Protein RalGEFRGL-1 Promotes Developmental Fidelity

2020 ◽  
Vol 21 (20) ◽  
pp. 7610 ◽  
Author(s):  
Tam Duong ◽  
Neal R. Rasmussen ◽  
David J. Reiner
Keyword(s):  
Birth Defects ◽  
Dual Function ◽  
Wild Type ◽  
Cell Fates ◽  
Vulval Development ◽  
C Elegans ◽  
Vulval Precursor Cells ◽  
Anchor Cell ◽  
The Impact ◽  
Wild Type Control

The C. elegans vulva is an excellent model for the study of developmental biology and cell–cell signaling. The developmental induction of vulval precursor cells (VPCs) to assume the 3°-3°-2°-1°-2°-3° patterning of cell fates occurs with 99.8% accuracy. During C. elegans vulval development, an EGF signal from the anchor cell initiates the activation of RasLET-60 > RafLIN-45 > MEKMEK-2 > ERKMPK-1 signaling cascade to induce the 1° cell. The presumptive 1° cell signals its two neighboring cells via NotchLIN-12 to develop 2° cells. In addition, RasLET-60 switches effectors to RalGEFRGL-1 > RalRAL-1 to promote 2° fate. Shin et al. (2019) showed that RalGEFRGL-1 is a dual-function protein in VPCs fate patterning. RalGEFRGL-1 functions as a scaffold for PDKPDK-1 > AktAKT-1/2 modulatory signaling to promote 1° fate in addition to propagating the RasLET-60 modulatory signal through RalRAL-1 to promote 2° fate. The deletion of RalGEFRGL-1 increases the frequency of VPC patterning errors 15-fold compared to the wild-type control. We speculate that RalGEFRGL-1 represents an “insulated switch”, whereby the promotion of one signaling activity curtails the promotion of the opposing activity. This property might increase the impact of the switch on fidelity more than two separately encoded proteins could. Understanding how developmental fidelity is controlled will help us to better understand the origins of cancer and birth defects, which occur in part due to the misspecification of cell fates.

scholarly journals The multivulva phenotype of certain Caenorhabditis elegans mutants results from defects in two functionally redundant pathways.

Genetics ◽  
1989 ◽  
Vol 123 (1) ◽  
pp. 109-121 ◽  
Author(s):  
E L Ferguson ◽  
H R Horvitz
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Lineage ◽  
Gene Families ◽  
Precursor Cells ◽  
Wild Type ◽  
Vulval Development ◽  
Vulval Precursor Cells ◽  
New Mutations ◽  
Intercellular Signal

Abstract We previously identified Caenorhabditis elegans mutants in which certain of the six vulval precursor cells adopt fates normally expressed by other vulval precursor cells. These mutants define genes that appear to function in the response to an intercellular signal that induces vulval development. The multivulva (Muv) phenotype of one such mutant, CB1322, results from an interaction between two unlinked mutations, lin-8(n111) II and lin-9(n112) III. In this paper, we identify 18 new mutations, which are alleles of eight genes, that interact with either lin-8(n111) or lin-9(n112) to generate a Muv phenotype. None of these 20 mutations alone causes any vulval cell lineage defects. The "silent Muv" mutations fall into two classes; hermaphrodites carrying a mutation of each class are Muv, while hermaphrodites carrying two mutations of the same class have a wild-type vulval phenotype. Our results indicate that the Muv phenotype of these mutants results from defects in two functionally-redundant pathways, thereby demonstrating that redundancy can occur at the level of gene pathways as well as at the level of gene families.

scholarly journals Caenorhabditis elegans lin-13, a Member of the LIN-35 Rb Class of Genes Involved in Vulval Development, Encodes a Protein With Zinc Fingers and an LXCXE Motif

Genetics ◽  
2000 ◽  
Vol 155 (3) ◽  
pp. 1127-1137 ◽  
Author(s):  
Alicia Meléndez ◽  
Iva Greenwald
Keyword(s):  
Caenorhabditis Elegans ◽  
Zinc Fingers ◽  
Null Alleles ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Vulval Development ◽  
Vulval Precursor Cells ◽  
Class B ◽  
Genes Encoding ◽  
Lxcxe Motif

Abstract The SynMuv genes appear to be involved in providing a signal that inhibits vulval precursor cells from adopting vulval fates in Caenorhabditis elegans. One group of SynMuv genes, termed class B, includes genes encoding proteins related to the tumor suppressor Rb and RbAp48, a protein that binds Rb. Here, we provide genetic evidence that lin-13 behaves as a class B SynMuv gene. We show that null alleles of lin-13 are temperature sensitive and maternally rescued, resulting in phenotypes ranging in severity from L2 arrest (when both maternal and zygotic activities are removed at 25°), to sterile Multivulva (when only zygotic activity is removed at 25°), to sterile non-Multivulva (when both maternal and zygotic activities are removed at 15°), to wild-type/class B SynMuv (when only zygotic activity is removed at 15°). We also show that LIN-13 is a nuclear protein that contains multiple zinc fingers and a motif, LXCXE, that has been implicated in Rb binding. These results together suggest a role for LIN-13 in Rb-mediated repression of vulval fates.

Reversal of cell fate determination in Caenorhabditis elegans vulval development

Development ◽  
1996 ◽  
Vol 122 (8) ◽  
pp. 2507-2515 ◽  
Author(s):  
S. Euling ◽  
V. Ambros
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Fate ◽  
Larval Stage ◽  
Cell Types ◽  
Wild Type ◽  
Vulval Development ◽  
Fate Determination ◽  
Developmental Arrest ◽  
Dauer Larva ◽  
Vulval Precursor Cells

In Caenorhabditis elegans, the fates of the multipotent vulval precursor cells (VPCs) are specified by intercellular signals. The VPCs divide in the third larval stage (L3) of the wild type, producing progeny of determined cell types. In lin-28 mutants, vulva development is similar to wild-type vulva development except that it occurs precociously, in the second larval stage (L2). Consequently, when lin-28 hermaphrodites temporarily arrest development at the end of L2 in the dauer larva stage, they have partially developed vulvae consisting of VPC progeny. During post-dauer development, these otherwise determined VPC progeny become reprogrammed back to the multipotent, signal-sensitive state of VPCs. Our results indicate that VPC fate determination by intercellular signals is reversible by dauer larva developmental arrest and post-dauer development.

Genetic studies of mei-1 gene activity during the transition from meiosis to mitosis in Caenorhabditis elegans.

Genetics ◽  
1993 ◽  
Vol 134 (1) ◽  
pp. 199-210 ◽  
Author(s):  
T R Clandinin ◽  
P E Mains
Keyword(s):  
Caenorhabditis Elegans ◽  
Null Alleles ◽  
Mitotic Spindles ◽  
Dominant Effect ◽  
Genetic Studies ◽  
In Trans ◽  
In Cis ◽  
Normal Meiosis

Abstract Genetic evidence suggests that the mei-1 locus of Caenorhabditis elegans encodes a maternal product required for female meiosis. However, a dominant gain-of-function allele, mei-1(ct46), can support normal meiosis but causes defects in subsequent mitotic spindles. Previously identified intragenic suppressors of ct46 lack functional mei-1 activity; null alleles suppress only in cis but other alleles arise frequently and suppress both in cis and in trans. Using a different screen for suppressors of the dominant ct46 defect, the present study describes another type of intragenic mutation that also arises at high frequency. These latter alleles appear to have reduced meiotic activity and retain a weakened dominant effect. Characterization of these alleles in trans-heterozygous combinations with previously identified mei-1 alleles has enabled us to define more clearly the role of the mei-1 gene product during normal embryogenesis. We propose that a certain level of mei-1 activity is required for meiosis but must be eliminated prior to mitosis. The dominant mutation causes mei-1 activity to function at mitosis; intragenic trans-suppressors act in an antimorphic manner to inactivate multimeric mei-1 complexes. We propose that inactivation of meiosis-specific functions may be an essential precondition of mitosis; failure to eliminate such functions may allow ectopic meiotic activity during mitosis and cause embryonic lethality.

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