Parental effects and phenotypic characterization of mutations that affect early development in Caenorhabditis elegans

Abstract We carried out a genetic screen for viable maternal-effect mutants to identify genes with a critical function relatively early in development. This type of mutation would not have been identified readily in previous screens for viable mutants and therefore could define previously unidentified genes. We screened 30,000 genomes and identified 41 mutations falling into 24 complementation groups. We genetically mapped these 24 loci; only two of them appear to correspond to previously identified genes. We present a partial phenotypic characterization of the mutants and a quantitative analysis of the degree to which they can be maternally or zygotically rescued.

Download Full-text

GENETIC AND PHENOTYPIC CHARACTERIZATION OF ROLLER MUTANTS OF CAENORHABDITIS ELEGANS

Genetics ◽

10.1093/genetics/95.2.317 ◽

1980 ◽

Vol 95 (2) ◽

pp. 317-339

Author(s):

George N Cox ◽

John S Laufer ◽

Meredith Kusch ◽

Robert S Edgar

Keyword(s):

Caenorhabditis Elegans ◽

Linkage Group ◽

Developmental Stages ◽

Developmental Process ◽

Phenotypic Characterization ◽

Gene Interactions ◽

C Elegans ◽

Nematode Cuticle ◽

Six Genes

ABSTRACT Eighty-eight mutants of C. elegans that display a roller phenotype (a helically twisted body) have been isolated and characterized genetically and phenotypically. The mutations are located in 14 different genes. Most genes contain a number of alleles. Their distribution among the chromosomes appears nonrandom, with seven of the genes being located on linkage group 11, some very closely linked. The phenotypes of the mutants suggest that there are five different classes of genes, each class representing a set of similar phenotypic effects: Left Roller (four genes), Right Roller (one gene), Left Squat (one gene), Right Squat (two genes) and Left Dumpy Roller (six genes). The classes of mutants differ with respect to a number of characteristics that include the developmental stages affected and the types of aberrations observed in cuticle structure. A variety of gene interactions were found, arguing that these genes are involved in a common developmental process. The presence of alterations in cuticle morphology strongly suggests that these genes are active in the formation of the nematode cuticle.

Download Full-text

The Levels of the RoRNP-Associated Y RNA Are Dependent Upon the Presence of ROP-1, the Caenorhabditis elegans Ro60 Protein

Genetics ◽

10.1093/genetics/151.1.143 ◽

1999 ◽

Vol 151 (1) ◽

pp. 143-150

Author(s):

Jean-Claude Labbé ◽

Siegfried Hekimi ◽

Luis A Rokeach

Keyword(s):

Caenorhabditis Elegans ◽

Laboratory Culture ◽

Culture Conditions ◽

Developmental Expression ◽

Phenotypic Characterization ◽

Major Protein ◽

Transgenic Expression ◽

C Elegans ◽

Developmental Expression Pattern

Abstract The Ro ribonucleoproteins (RoRNP) consist of at least one major protein of 60 kD, Ro60, and one small associated RNA, designated Y RNA. Although RoRNP have been found in all vertebrate species examined so far, their function remains unknown. The Caenorhabditis elegans rop-1 gene previously has been identified as encoding a Ro60 homologue. We report here the phenotypic characterization of a C. elegans strain in which rop-1 has been disrupted. This is the first report regarding the inactivation of a major RoRNP constituent in any organism. The rop-1 mutant worms display no visible defects. However, at the molecular level, the disruption of rop-1 results in a dramatic decrease in the levels of the ROP-1-associated RNA (CeY RNA). Moreover, transgenic expression of wild-type rop-1 partially rescues the levels of CeY RNA. Considering that transgenes are poorly expressed in the germline, the fact that the rescue is only partial is most likely related to the high abundance of the CeY RNA in the adult germline and in embryos. The developmental expression pattern and localization of CeY RNA suggest a role for this molecule during embryogenesis. We conclude that, under laboratory culture conditions, ROP-1 does not play a crucial role in C. elegans.

Download Full-text

The Caenorhabditis elegans Sex Determination Gene mog-1 Encodes a Member of the DEAH-Box Protein Family

Molecular and Cellular Biology ◽

10.1128/mcb.19.3.2189 ◽

1999 ◽

Vol 19 (3) ◽

pp. 2189-2197 ◽

Cited By ~ 43

Author(s):

Alessandro Puoti ◽

Judith Kimble

Keyword(s):

Caenorhabditis Elegans ◽

Germ Line ◽

Regulatory Element ◽

Residual Activity ◽

Normal Growth ◽

Null Alleles ◽

Phenotypic Characterization ◽

Rna Regulation ◽

And Control

ABSTRACT In the Caenorhabditis elegans hermaphrodite germ line, the sex-determining gene fem-3 is repressed posttranscriptionally to arrest spermatogenesis and permit oogenesis. This repression requires a cis-acting regulatory element in the fem-3 3′ untranslated region; the FBF protein, which binds to this element; and at least six mog genes. In this paper, we report the molecular characterization of mog-1 as well as additional phenotypic characterization of this gene. Themog-1 gene encodes a member of the DEAH-box family. Threemog-1 alleles possess premature stop codons and are likely to be null alleles, and one is a missense mutation and is likely to retain residual activity. mog-1 mRNA is expressed in both germ line and somatic tissues and appears to be ubiquitous. The MOG-1 DEAH-box protein is most closely related to proteins essential for splicing in the yeast Saccharomyces cerevisiae, but splicing appears to occur normally in a mog-1-null mutant. In addition to its involvement in the sperm-oocyte switch and control of fem-3, zygotic mog-1 is required for robust germ line proliferation and for normal growth during development. We suggest that mog-1 plays a broader role in RNA regulation than previously considered.

Download Full-text

Identification of grandchildless loci whose products are required for normal germ-line development in the nematode Caenorhabditis elegans.

Genetics ◽

10.1093/genetics/129.4.1061 ◽

1991 ◽

Vol 129 (4) ◽

pp. 1061-1072 ◽

Cited By ~ 6

Author(s):

E E Capowski ◽

P Martin ◽

C Garvin ◽

S Strome

Keyword(s):

Drosophila Melanogaster ◽

Caenorhabditis Elegans ◽

Germ Cells ◽

Structural Integrity ◽

Germ Line ◽

Phenotypic Characterization ◽

Nematode Caenorhabditis Elegans ◽

Homozygous Mutant ◽

Germ Granules

Abstract To identify genes that encode maternal components required for development of the germ line in the nematode Caenorhabditis elegans, we have screened for mutations that confer a maternal-effect sterile or "grandchildless" phenotype: homozygous mutant hermaphrodites produced by heterozygous mothers are themselves fertile, but produce sterile progeny. Our screens have identified six loci, defined by 21 mutations. This paper presents genetic and phenotypic characterization of four of the loci. The majority of mutations, those in mes-2, mes-3 and mes-4, affect postembryonic germ-line development; the progeny of mutant mothers undergo apparently normal embryogenesis but develop into agametic adults with 10-1000-fold reductions in number of germ cells. In contrast, mutations in mes-1 cause defects in cytoplasmic partitioning during embryogenesis, and the resulting larvae lack germ-line progenitor cells. Mutations in all of the mes loci primarily affect the germ line, and none disrupt the structural integrity of germ granules. This is in contrast to grandchildless mutations in Drosophila melanogaster, all of which disrupt germ granules and affect abdominal as well as germ-line development.

Download Full-text

Functional characterization of Caenorhabditis elegans cbs-2 gene during meiosis

Scientific Reports ◽

10.1038/s41598-020-78006-w ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Pamela Santonicola ◽

Marcello Germoglio ◽

Domenico Scotto d’Abbusco ◽

Adele Adamo

Keyword(s):

Dna Damage ◽

Caenorhabditis Elegans ◽

Functional Characterization ◽

Genotoxic Stress ◽

Phenotypic Characterization ◽

Chromosome Fragmentation ◽

C Elegans ◽

Synaptonemal Complex Formation ◽

Induced Apoptosis

AbstractCystathionine β-synthase (CBS) is a eukaryotic enzyme that maintains the cellular homocysteine homeostasis and catalyzes the conversion of homocysteine to L-cystathionine and Hydrogen sulfide, via the trans-sulfuration pathway. In Caenorhabditis elegans, two cbs genes are present: cbs-1 functions similarly as to human CBS, and cbs-2, whose roles are instead unknown. In the present study we performed a phenotypic characterization of the cbs-2 mutant. The null cbs-2 mutant is viable, fertile and shows the wild-type complement of six bivalents in most oocyte nuclei, which is indicative of a correct formation of crossover recombination. In absence of synaptonemal complex formation (syp-2 mutant), loss of cbs-2 leads to chromosome fragmentation, suggesting that cbs-2 is essential during inter-sister repair. Interestingly, although proficient in the activation of the DNA damage checkpoint after exposure to genotoxic stress, the cbs-2 mutant is defective in DNA damage-induced apoptosis in meiotic germ cells. These results suggest possible functions for CBS-2 in meiosis, distinct from a role in the trans-sulfuration pathway. We propose that the C. elegans CBS-2 protein is required for both inter-sister repair and execution of DNA damage-induced apoptosis.

Download Full-text

The glycomes of Caenorhabditis elegans and other model organisms

Biochemical Society Symposium ◽

10.1042/bss0690117 ◽

2002 ◽

Vol 69 ◽

pp. 117-134 ◽

Cited By ~ 47

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.

Download Full-text