Caenorhabditis elegans lin-25: cellular focus, protein expression and requirement for sur-2 during induction of vulval fates

Induction of vulval fates in the C. elegans hermaphrodite is mediated by a signal transduction pathway involving Ras and MAP kinase. Previous genetic analysis has suggested that two potential targets of this pathway in the vulva precursor cells are two novel proteins, LIN-25 and SUR-2. In this report, we describe further studies of lin-25. The results of a genetic mosaic analysis together with those of experiments in which lin-25 was expressed under the control of an heterologous promoter suggest that the major focus of lin-25 during vulva induction is the vulva precursor cells themselves. We have generated antisera to LIN-25 and used these to analyse the pattern of protein expression. LIN-25 is present in all six precursor cells prior to and during vulva induction but later becomes restricted to cells of the vulval lineages. Mutations in genes in the Ras/MAP kinase pathway do not affect the pattern of expression but the accumulation of LIN-25 is reduced in the absence of sur-2. Overexpression of LIN-25 does not rescue sur-2 mutant defects suggesting that LIN-25 and SUR-2 may function together. LIN-25 is also expressed in the lateral hypodermis. Overexpression of LIN-25 disrupts lateral hypodermal cell fusion, suggesting that lin-25 may play a role in regulating cell fusions in C. elegans.

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The MAP kinase pathway coordinates crossover designation with disassembly of synaptonemal complex proteins during meiosis

eLife ◽

10.7554/elife.12039 ◽

2016 ◽

Vol 5 ◽

Cited By ~ 11

Author(s):

Saravanapriah Nadarajan ◽

Firaz Mohideen ◽

Yonatan B Tzur ◽

Nuria Ferrandiz ◽

Oliver Crawley ◽

...

Keyword(s):

Map Kinase ◽

Synaptonemal Complex ◽

Chromosome Segregation ◽

Meiotic Chromosome ◽

Late Pachytene ◽

C Elegans ◽

Map Kinase Pathway ◽

Rho Gef ◽

Kinase Signaling Pathway ◽

Kinase Pathway

Asymmetric disassembly of the synaptonemal complex (SC) is crucial for proper meiotic chromosome segregation. However, the signaling mechanisms that directly regulate this process are poorly understood. Here we show that the mammalian Rho GEF homolog, ECT-2, functions through the conserved RAS/ERK MAP kinase signaling pathway in the C. elegans germline to regulate the disassembly of SC proteins. We find that SYP-2, a SC central region component, is a potential target for MPK-1-mediated phosphorylation and that constitutively phosphorylated SYP-2 impairs the disassembly of SC proteins from chromosomal domains referred to as the long arms of the bivalents. Inactivation of MAP kinase at late pachytene is critical for timely disassembly of the SC proteins from the long arms, and is dependent on the crossover (CO) promoting factors ZHP-3/RNF212/Zip3 and COSA-1/CNTD1. We propose that the conserved MAP kinase pathway coordinates CO designation with the disassembly of SC proteins to ensure accurate chromosome segregation.

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Examination of signal transduction pathway of stimulated B1 and B2 kinin receptors; MAP kinase pathway to AP-1 translocation in HEK 293 cells

Immunopharmacology ◽

10.1016/s0162-3109(99)00055-7 ◽

1999 ◽

Vol 45 (1-3) ◽

pp. 35-38 ◽

Cited By ~ 8

Author(s):

Hiroaki Naraba ◽

Akinori Ueno ◽

Mineka Yoshimura ◽

Yae Kosugi ◽

Sachiko Oh-ishi

Keyword(s):

Signal Transduction ◽

Map Kinase ◽

Signal Transduction Pathway ◽

Transduction Pathway ◽

Hek 293 ◽

Hek 293 Cells ◽

Kinin Receptors ◽

293 Cells ◽

Map Kinase Pathway ◽

Kinase Pathway

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The expression of TGFβ signal transducers in the hypodermis regulates body size inC. elegans

Development ◽

10.1242/dev.129.21.4989 ◽

2002 ◽

Vol 129 (21) ◽

pp. 4989-4998 ◽

Cited By ~ 4

Author(s):

Jianjun Wang ◽

Rafal Tokarz ◽

Cathy Savage-Dunn

Keyword(s):

Nervous System ◽

Body Size ◽

Protein Accumulation ◽

Type I ◽

Loss Of Function ◽

Signal Transducers ◽

C Elegans ◽

Genetic Mosaic ◽

Mosaic Analysis ◽

Necessary And Sufficient

In C. elegans, a TGFβ-related signaling pathway regulates body size. Loss of function of the signaling ligand (dbl-1),receptors (daf-4 and sma-6) or Smads (sma-2, sma-3and sma-4) results in viable, but smaller animals because of a reduction in postembryonic growth. We have investigated the tissue specificity of this pathway in body size regulation. We show that different tissues are reduced in size by different proportions, with hypodermal blast cell size most closely proportional to body size. We show that SMA-3 Smad is expressed in pharynx, intestine and hypodermis, as has been previously reported for the type I receptor SMA-6. Furthermore, we find that SMA-3::GFP is nuclear localized in all of these tissues, and that nuclear localization is enhanced by SMA-6 activity. Interestingly, SMA-3 protein accumulation was found to be negatively regulated by the level of Sma/Mab pathway activity. Using genetic mosaic analysis and directed expression of SMA-3, we find that SMA-3 activity in the hypodermis is necessary and sufficient for normal body size. Asdbl-1 is expressed primarily in the nervous system, these results suggest a model in which postembryonic growth of hypodermal cells is regulated by TGFβ-related signaling from the nervous system to the hypodermis.

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Three genes of the MAP kinase cascade, mek-2, mpk-1/sur-1 and let-60 ras, are required for meiotic cell cycle progression in Caenorhabditis elegans

Development ◽

10.1242/dev.121.8.2525 ◽

1995 ◽

Vol 121 (8) ◽

pp. 2525-2535 ◽

Cited By ~ 34

Author(s):

D.L. Church ◽

K.L. Guan ◽

E.J. Lambie

Keyword(s):

Cell Cycle ◽

Caenorhabditis Elegans ◽

Map Kinase ◽

Germ Cells ◽

Cell Cycle Progression ◽

Extended Period ◽

Meiotic Cell ◽

Cycle Progression ◽

C Elegans ◽

Genetic Mosaic

In the germline of Caenorhabditis elegans hermaphrodites, meiotic cell cycle progression occurs in spatially restricted regions. Immediately after leaving the distal mitotic region, germ cells enter meiosis and thereafter remain in the pachytene stage of first meiotic prophase for an extended period. At the dorsoventral gonadal flexure, germ cells exit pachytene and subsequently become arrested in diakinesis. We have found that exit from pachytene is dependent on the function of three members of the MAP kinase signaling cascade. One of these genes, mek-2, is a newly identified C. elegans MEK (MAP kinase kinase). The other two genes, mpk-1/sur-1 (MAP kinase) and let-60 ras, were previously identified based on their roles in vulval induction and are shown here to act in combination with mek-2 to permit exit from pachytene. Through genetic mosaic analysis, we demonstrate that the expression of mpk-1/sur-1 is required within the germline to permit exit from pachytene.

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Twitchin kinase interacts with MAPKAP kinase 2 in Caenorhabditis elegans striated muscle

Molecular Biology of the Cell ◽

10.1091/mbc.e14-05-1009 ◽

2015 ◽

Vol 26 (11) ◽

pp. 2096-2111 ◽

Cited By ~ 4

Author(s):

Yohei Matsunaga ◽

Hiroshi Qadota ◽

Miho Furukawa ◽

Heejoo (Helen) Choe ◽

Guy M. Benian

Keyword(s):

Caenorhabditis Elegans ◽

Map Kinase ◽

Striated Muscle ◽

P38 Map Kinase ◽

Dynamics Simulation ◽

Catalytic Core ◽

C Elegans ◽

Map Kinase Pathway ◽

Pulling Force

In Caenorhabditis elegans, twitchin is a giant polypeptide located in muscle A-bands. The protein kinase of twitchin is autoinhibited by 45 residues upstream (NL) and 60 residues downstream (CRD) of the kinase catalytic core. Molecular dynamics simulation on a twitchin fragment revealed that the NL is released by pulling force. However, it is unclear how the CRD is removed. To identify proteins that may remove the CRD, we performed a yeast two-hybrid screen using twitchin kinase as bait. One interactor is MAK-1, C. elegans orthologue of MAPKAP kinase 2. MAPKAP kinase 2 is phosphorylated and activated by p38 MAP kinase. We demonstrate that the CRD of twitchin is important for binding to MAK-1. mak-1 is expressed in nematode body wall muscle, and antibodies to MAK-1 localize between and around Z-disk analogues and to the edge of A-bands. Whereas unc-22 mutants are completely resistant, mak-1 mutants are partially resistant to nicotine. MAK-1 can phosphorylate twitchin NL-Kin-CRD in vitro. Genetic data suggest the involvement of two other mak-1 paralogues and two orthologues of p38 MAP kinase. These results suggest that MAK-1 is an activator of twitchin kinase and that the p38 MAP kinase pathway may be involved in the regulation of twitchin.

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Mosaic Analysis Using a ncl-1 (+) Extrachromosomal Array Reveals That lin-31 Acts in the Pn.p Cells During Caenorhabditis elegans Vulval Development

Genetics ◽

10.1093/genetics/143.3.1181 ◽

1996 ◽

Vol 143 (3) ◽

pp. 1181-1191 ◽

Cited By ~ 2

Author(s):

Leilani M Miller ◽

David A Waxing ◽

Stuart K Kim

Keyword(s):

Caenorhabditis Elegans ◽

The Body ◽

Specific Cell ◽

Vulval Development ◽

C Elegans ◽

Genetic Mosaic ◽

Extrachromosomal Array ◽

Mosaic Analysis ◽

Putative Transcription Factor ◽

Sites Of Action

Abstract We describe a genetic mosaic analysis procedure in which Caenorhabditis elegans mosaics are generated by spontaneous loss of an extrachromosomal array. This technique allows almost any C. elegans gene that can be used in germline transformation experiments to be used in mosaic analysis experiments. We identified a cosmid clone that rescues the mutant phenotype of ncl-1, so that this cell-autonomous marker could be used to analyze mosaic animals. To determine the sites of action for unc-29 and lin-31, an extrachromosomal array was constructed containing the ncl-1(+) cosmid linked to lin-31(+) and unc-29(+) cosmids. This array is mitotically unstable and can be lost to produce a clone of mutant cells. The specific cell division at which the extrachromosomal array had been lost was deduced by scoring the Ncl phenotypes of individual cells in genetic mosaics. The Unc-29 and Lin-31 phenotypes were then scored in these animals to determine in which cells these genes are required. This analysis showed that unc-29, which encodes a subunit of the acetylcholine receptor, acts in the body muscle cells. Furthermore, lin-31, which specifies cell fates during vulval induction and encodes a putative transcription factor similar to HNF-3/fork head, acts in the Pn.p cells

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