Hajarnavis A et al. (2006) RNA "A conserved sequence motif in 3' untranslated regions of ribosomal protein mRNAs in nematodes."

Hajarnavis A, Durbin R

[RNA, 2006]

The 3'' untranslated regions (3'' UTR) of eukaryotic genes can contain motifs involved in regulation of gene expression or localization at the post-transcriptional level. This study concerns the identification of novel, conserved elements in 3'' UTRs of many ribosomal protein mRNAs in Caenorhabditis elegans and Caenorhabditis briggsae. Analysis of the region around the polyadenylation signal in many ribosomal protein mRNAs indicates the conservation of a sequence motif UUGUU occurring both before and immediately after the polyadenylation signal. Building a statistical model of this motif and searching a database of C. elegans 3'' UTRs reveals that this motif is also present in the 3'' UTR of some genes involved in translation and ribosome maturation, among others. We suggest that this signal may be involved in translation or other message-level regulation of ribosomal genes in C. elegans.

Chinnaiyan AM et al. (1997) Nature "Role of CED-4 in the activation of CED-3."

Koonin EV, Dixit VM, Chaudhary D, O'Rourke K, Chinnaiyan AM

[Nature, 1997]

Genetic analyses of the nematode Caenorhabditis elegans have identified three core components of the cell-death apparatus. CED-3 and CED-4 promote, whereas CED-9 inhibits cell death. Recent studies indicate that CED-4 might interact independently with CED-3 and CED-9, forming the crux of a multicomponent death complex. But except for its role as an adaptor molecule, little is known about CED-4 function. A clue came with the observation that mutation of the phosphate-binding loop (P-loop) of CED-4 disrupts its ability to induce chromatin condensation in yeast. Further, a P-loop mutant of CED-4 (CED-4K165R) fails to process CED-3 in vivo, both in insect and mammalian cells (unpublished). We now confirm that CED-4 induces CED-3 activation and subsequent apoptosis, and that the process requires binding of ATP.

Petcherski AG et al. (2000) Curr Biol "Mastermind is a putative activator for Notch."

Kimble J, Petcherski AG

[Curr Biol, 2000]

During signaling by the Notch receptor, Notch's intracellular domain is cleaved, moves to the nucleus and associates with a DNA-binding protein of the CSL class (CSL for CBF1, Suppressor of Hairless (Su(H)), LAG-1); as a result, target genes are transcriptionally activated (reviewed in [1,2]). In Caenorhabditis elegans, a glutamine-rich protein called LAG-3 forms a ternary complex with the Notch intracellular domain and LAG-1 and appears to serve as a transcriptional activator that is critical for signaling [3]. Although database searches failed to identify a LAG-3-related protein, we surmised that Notch signaling in other organisms might involve an analogous activity.

Burglin TR (1994) Trends Biochem Sci "A Caenorhabditis elegans prospero homologue defines a novel domain."

Burglin TR

[Trends Biochem Sci, 1994]

The Drosophila gene prospero (pros) encodes a sequence motif with similarity to homeodomains. This homeodomain motif is highly atypical, since it contains three extra residues between helix 2 and helix 3. Furthermore, some usually highly conserved residues are not conserved (for a comparison of atypical homeodomains see Ref. 4). ..

Rajaram S et al. (2000) Genesis "The sequence and associated null phenotype of a C. elegans neurocalcin-like gene."

Morgan PG, Rajaram S, Sedensky MM

[Genesis, 2000]

The neuronal calcium sensor (NCS) proteins belong to a subfamily of the EF-hand calcium binding proteins. These proteins are primarily expressed in the nervous system and currently include more than 20 members across species [Nakayama et al., J Mol Evol 34:416-448, 1992]. Two homologues of the ncs genes, Ce-ncs-1 and Ce-ncs-2, have recently been identified in the nematode C. elegans. Here we report the cDNA sequence of a third C. elegans ncs homologue, Ce-ncs-3. We demonstrate that a null mutation in this gene caused by a large deletion in the locus does not confer a visible phenotype in C. elegans. This, in addition to the strong homology between Ce-NCS-3 and the other C. elegans NCS proteins, may indicate functional redundancy between the three genes.

Sung M et al. (2017) FEBS Lett "Depletion of cdc-25.3, a C. elegans ortholog of cdc25, increases physiological germline apoptosis."

Kawasaki I, Sung M, Shim YH

[FEBS Lett, 2017]

In Caenorhabditis elegans hermaphrodites, physiological germline apoptosis is higher in cdc-25.3 mutants than in wild type. The elevated germline apoptosis in cdc-25.3 mutants seems to be induced by accumulation of double-stranded DNA breaks (DSBs). Both DNA-damage and synapsis checkpoint genes are required to increase the germline apoptosis. Notably, the number of germ cells that lose P-granule components, PGL-1 and PGL-3, increase in cdc-25.3 mutants, and the increase in germline apoptosis requires the activity of SIR-2.1, a Sirtuin ortholog. These results suggest that elevation of germline apoptosis in cdc-25.3 mutants is induced by accumulation of DSBs, leading to a loss of PGL-1 and PGL-3 in germ cells, which promotes cytoplasmic translocation of SIR-2.1, and finally activates the core apoptotic machinery. This article is protected by copyright. All rights reserved.

Edgar RS et al. (1977) Science "The nematode Caenorhabditis elegans: a new organism for intensive biological study."

Edgar RS, Wood WB

[Science, 1977]

At a recent conference in Woods Hole, Massachusetts, investigators met to discuss the nematode Caenorhabditis elegans. This free-living worm may, according to some workers, become the Escherichia coli or at least the bacteriophage T4 of the animal world. Small (about 1mm in length) and semitransparent, C. elegans provides for research the advantages of a short life cycle (3 days) and a simple anatomy-it contains about 810 nongonadal nuclei. It is both easy to cultivate, on E. coli as a food source, and convenient for genetic analysis. Its genes are carried on five autosomes and a sex chromosome (X), and it has a genome size about 20 times that of E. coli. It generally reproduces as a self-fertilizing hermaphrodite (XX), but occasional males (XO), which arise by nondisjunction, permit sexual reproduction as well....

Yin J et al. (2015) Genesis "Multiple cis elements and GATA factors regulate a cuticle collagen gene in Caenorhabditis elegans."

Madaan U, Savage-Dunn C, Park A, Aftab N, Yin J

[Genesis, 2015]

The cuticle of the nematode Caenorhabditis elegans is a specialized extracellular matrix whose major component is collagen. Cuticle collagens are encoded by a large multigene family consisting of more than 150 members. Cuticle collagen genes are expressed in epidermis (hypodermis) and may be stage-specific or cyclically expressed. We identified cuticle collagen genes as transcriptional targets of the DBL-1 TGF--related signaling pathway. These studies prompted us to investigate the cis-regulatory sequences required for transcription of one of the target genes, col-41. We generated reporter constructs that reproduce stage- and tissue-specific expression of fluorescent markers. We identify four conserved sequence elements that are required for transcription of reporters. Finally, we provide evidence that col-41 expression is controlled by a sequence element containing two GATA sites and by the epidermal GATA transcription factors ELT-1 and ELT-3.

Langerak S et al. (2018) Genesis "Remodeling of the endoplasmic reticulum in C. elegans oocytes is regulated by CGH-1."

Langerak S, Leroux D, Patterson JR, Trombley A, Schisa JA, Wood MP, Couch A

[Genesis, 2018]

A key aspect of development in all metazoans is remodeling at the cellular level. During the development of gametes, remodeling occurs throughout the germ line. When C. elegans hermaphrodites become depleted of sperm after 4 days of adulthood, significant cellular remodeling occurs within the meiotically-arrested oocytes, including the formation of ribonucleoprotein (RNP) granules. Since major remodeling of the endoplasmic reticulum (ER) occurs in early embryos, we investigated the extent of ER remodeling in meiotically-arrested oocytes. We found, using a combination of fluorescence reporters and transmission electron microscopy (TEM), that the ER in arrested oocytes accumulates in patches and sheets that are enriched at the cortex. Our findings suggest this remodeling is not due to simple displacement by large amounts of yolk that accumulate in arrested oocytes, and instead may be genetically regulated. We further identified the Ddx6 RNA helicase, CGH-1, as a key regulator of ER in the germ line. In cgh-1(tn691) oocytes, we detected cortical ER patches as well as aberrant granules of the RNA-binding proteins, PAB-1, MEX-3, and CGH-1. Taken together, our results suggest the possibility that the spatial organization of RNA binding proteins may regulate the translation of mRNAs associated with the ER that in turn, controls the organization of the ER in the adult germ line. This article is protected by copyright. All rights reserved.

Abete-Luzi P et al. (2018) Genesis "Regulation of C. elegans L4 cuticle collagen genes by the heterochronic protein LIN-29."

Abete-Luzi P, Eisenmann DM

[Genesis, 2018]

The cuticle, the outer covering of the nematode C. elegans, is synthesized five times during the worm's life by the underlying hypodermis. Cuticle collagens, the major cuticle component, are encoded by a large family of col genes and, interestingly, many of these genes express predominantly at a single developmental stage. This temporal preference motivated us to investigate the mechanisms underlying col gene expression and here we focus on a subset of col genes expressed in the L4 stage. We identified minimal promoter regions of <300 bp for col-38, col-49, and col-63. In these regions, we predicted cis-regulatory sequences and evaluated their function in vivo via mutagenesis of a col-38p::yfp reporter. We used RNAi to study the requirement for candidate transcription regulators ELT-1 and ELT-3, LIN-29, and the LIN-29 co-factor MAB-10, and found LIN-29 to be necessary for the expression of four L4-specific genes (col-38, col-49, col-63 and col-138). Temporal misexpression of LIN-29 was also sufficient to activate these genes at a different developmental stage. The LIN-29 DNA-binding domain bound the col-38, col-49, and col-63 minimal promoters in vitro. For col-38 we showed that the LIN-29 sites necessary for reporter expression in vivo are also bound in vitro: this is the first identification of specific binding sites for LIN-29 necessary for in vivo target gene expression. This article is protected by copyright. All rights reserved.