Philippe Vaglio et al. (2001) International C. elegans Meeting "WorfDB: The C. elegans ORFeome database"

Marc Vidal, Jerome Reboul, Jean-Francois Rual, Philippe E Lamesch, David E Hill, Philippe Vaglio

[International C. elegans Meeting, 2001]

Kaempfer, Philipp et al. (2015) International Worm Meeting "Improved C. briggsae genome assembly."

Dahl, Andreas, Schloissnig, Siegfried, Tinney, Mathew, Kaempfer, Philipp, Sarov, Mihail, Winkler, Sylke, Merret, Stephanie

[International Worm Meeting, 2015]

C. briggsae is and essential sister model to C. elegans for comparative genomics and evo-devo studies. Since the original genome was published in 2003 the genome assembly has been improved several times but it is still incomplete. We attempted to improve the quality of the C. briggsae genome assembly using the Pacific Bioscience sequencing platform and the more conventional approach of Illumina paired-end sequencing of total genomic DNA and an arrayed genomic fosmid library. We find that the PacBio data is sufficient for a very high quality assembly even in highly repetitive regions.The C. briggsae sequencing was our proof of principle experiment before we move on to other currently unsequenced or partially sequenced genomes that we need in order to study the evolutionary divergence of developmental programs. The meeting will be a good opportunity to compare our agenda with other similar initiatives to avoid duplication of effort and to optimise the use our resources.

Philippe Vaglio et al. (2002) West Coast Worm Meeting "THE C. ELEGANS ORFEOME CLONING PROJECT : VERSION 1.0"

Troy Moore, Jerome Reboul, Monica Martinez, Mike Brasch, Alban Chesneau, Marc Vidal, David E Hill, Jean-Francois Rual, Lynn Doucette-Stamm, Hongmei Lee, Philippe Vaglio, Nicolas Bertin, Laurent Jacotot, Philippe Lamesch, Jim Hartley, Christopher Armstrong

[West Coast Worm Meeting, 2002]

In addition to the draft of the human genome sequence, the genome sequences of an increasing number of model organisms are now available. This sequence information is expected to revolutionize the way biological questions can be addressed. Molecular mechanisms should now be approachable on a more global scale in the context of (nearly) complete sets of genes, rather than by analyzing genes individually. However most protein-encoding open reading frames (ORFs) predicted from these sequencing projects have remained completely uncharacterized at the functional level. For example, out of 19,000 ORFs predicted from the C. elegans genome sequence, the function of approximately 1,200 has been experimentally characterized during the last 30 years. Functional genomics and proteomics address this limitation through the simultaneous annotation of large numbers of predicted ORFs. Despite the urgent need for large-scale functional annotation projects, functional genomics approaches have remained relatively undeveloped in multicellular organisms, primarily because of the lack of suitable methods to clone large numbers of protein-encoding ORFs into many different expression vectors. Indeed, most strategies developed in these projects are based upon the expression of large numbers of proteins in exogenous settings and in fusion with relevant tags. In order to facilitate these different proteome-wide projects, a complete set of ORFs (or ?ORFeome?) will need to be cloned multiple times into many different expression vectors for each model organism of interest. To achieve this goal, one solution is to clone an ORFeome of interest once and for all in a "resource" vector allowing a convenient transfer to various expression vectors. To clone the C. elegans ORFeome into various expression vectors, we use a recombination cloning technique referred to as Gateway. This technique allows both the initial cloning of ORFs and their subsequent transfer into different expression vectors by site-specific recombination in vitro. We have now finished the first part of the C. elegans ORFeome project which was to attempt to clone the ~19,000 predicted ORFs. We will present the success rate in cloning of the ORFs and the overall quality of the ORFeome to date. We will also describe how the ORFeome was used as a new approach to construct a ~100% normalized yeast two-hybrid library. Finally we will show how we could transfer thousands of ORFs from the resource clones into a dozen different expression vectors for uses in large-scale functional genomic and proteomic projects such as gene inactivation by RNAi, protein interaction mapping by yeast two-hybrid, protein production for structural genomics etc.

J Connolly et al. (1999) International C. elegans Meeting "A C. elegans-based study of Huntington Disease-associated pathways"

M Chalfie, C Neri, S Holbert, I Denghien, C Philippe, J Connolly, S Moriniere

[International C. elegans Meeting, 1999]

Polyglutamine (polyQ) expansion in huntingtin (htt) underlies Huntington's disease (HD). The mechanisms which cause neuron dysfunction and degeneration in HD are unknown. To identify HD-associated pathways, we have undertaken a C. elegans-based study that relies on two approaches: screening for proteins able to interact with htt, and screening for genetic suppressors of mutated htt-dependent phenotypes in transgenic worms. We used the mec-3 promoter (mec-3p) to express GFP fusions which contain a short N-terminal fragment of htt with a normal (17 units) or expanded (84 units) polyQ tract. The mec-3 gene is expressed in 10 neurons including the six touch receptor neurons AVM, ALML, ALMR, PVM, PLML and PLMR. Worms expressing the long polyQ construct were less than 30% and 50% Mec at the tail at Day 1 and 7, respectively. Worms expressing the short polyQ construct or animals with GFP expression driven by mec-3p were less than 7% and 30% Mec at the tail over the same time-frame. Cell death was not observed in these experiments. There was an imperfect correlation between the perinuclear aggregation of GFP fusions in PLM cells and the Mec phenotypes observed. Our preliminary data suggest that N-terminal htt fragments with a long polyQ induce touch insensitivity when expressed in touch receptor neurons, and that transgenic worms expressing mutated htt might be useful for screening for genetic suppressors of behavioural phenotypes. We have screened a C. elegans cDNA library (R. Barstead, OMRC, OK) by using two-hybrid selection in yeast. The screening with a N-terminal htt fragment containing 15 Glns allowed the identification of a new Htt Interacting Protein (wHIP3). WHIP3 shows variation of interaction between normal and mutated htt, and is homologous with a human protein (hHIP3) encoded by a gene expressed in the brain. Additional studies are being performed in order to test whether hHIP3 might be involved in HD. We will present the results of experiments based on both approaches.

Dirksen, Philipp et al. (2011) International Worm Meeting "Natural ecology of C. elegans in Germany."

Petersen, Carola, Peters, Fabian, Chen, Wei, Dirksen, Philipp, Dierking, Katja, Schulenburg, Hinrich

[International Worm Meeting, 2011]

Taking a step outside the laboratory and exploring C. elegans in its natural habitat is part of our attempt to combine ecological, evolutionary, and molecular approaches to study host-microbe interactions under more realistic conditions. Here we report our recent findings on natural C. elegans populations from Germany. In 2010, we isolated nematodes from two different locations, Kiel at the Baltic Sea and Munster (Roxel) in northwest Germany. These samples are currently used to assess the diversity of associated microbial organisms, including pathogens as well as possible mutualists. We furthermore evaluate natural variation in ecologically relevant traits such as pathogen resistance, microbe-related choice behaviors and also mating incompatibilities. These analyses serve to identify the selective constraints that act on natural C. elegans populations and that are thus likely important determinants of nematode life-history characteristics as well as the underlying molecular signaling cascades.

Bhagwati P Gupta et al. (2002) West Coast Worm Meeting "Genetic analysis of the vulval mutants in C. briggsae"

Shahla Gharib, Bhagwati P Gupta, Paul W Sternberg, Jennifer X Li

[West Coast Worm Meeting, 2002]

To understand the evolution of developmental mechanisms, we are doing a comparative analysis of vulval patterning in C. elegans and C. briggsae. C. briggsae is closely related to C. elegans and has identical looking vulval morphology. However, recent studies have indicated subtle differences in the underlying mechanisms of development. The recent completion of C. briggsae genome sequence by the C. elegans Sequencing Consortium is extremely valuable in identifying the conserved genes between C. elegans and C. briggsae.

Oomura, S. et al. (2019) International Worm Meeting "Early embryogenesis of C. inopinata, a sibling species of C.elegans."

Matsumura, Y., Haruta, N., Hoshi, Y., Sugimoto, A., Oomura, S.

[International Worm Meeting, 2019]

C. inopinata is a newly discovered sibling species of C. elegans. Despite their phylogenetic closeness, they have many differences in morphology and ecology. For example, while C. elegans is hermaphroditic, C. inopinata is gonochoristic; C. inopinata is nearly twice as long as C. elegans. A comparative analysis of C. elegans and C. inopinata enables us to study how genomic changes cause these phenotypic differences. In this study, we focused on early embryogenesis of C. inopinata. First, by the microparticle bombardment method we made a C. inopinata line that express GFP::histone in whole body, and compared the early embryogenesis with C. elegans by DIC and fluorescent live imaging. We found that the position of pronuclei and polar bodies were different between these two species. In C. elegans, the female and male pronuclei first become visible in anterior and posterior sides, respectively, then they meet at the center of embryo. On the other hand, the initial position of pronuclei were more closely located in C. inopinata. Also, the polar bodies usually appear in the anterior side of embryo in C. elegans, but they appeared at random positions in C. inopinata. Therefore, we infer that C. inopinata may have a different polarity formation mechanism from that in C. elegans. We are also analyzing temperature dependency of embryogenesis in C. inopinata, whose optimal temperature is ~7 degree higher than that in C. elegans.

Karin Kiontke et al. (2008) Development & Evolution Meeting "New Phylogeny Of Caenorhabditis Including Recently Discovered Species"

David Fitch, Karin Kiontke, Marie-Anne FELIX

[Development & Evolution Meeting, 2008]

Recently, seven new Caenorhabditis have been discovered, bringing the number of Caenorhabditis species in culture to 17, 10 of which are undescribed. To elucidate the relationships of the new species to the five species with sequenced genomes, we have used sequence data from two rRNA genes and several protein-coding genes for reconstructing the phylogenetic tree of Caenorhabditis. Four new species (spp. 5, 9, 10, 11) group within the so-called Elegans group of Caenorhabditis, with C. elegans being the first branch. Whereas none of them is likely to be the sister species of C. elegans, we now know of two close relatives of C. briggsae-C. sp. 5 and C. sp. 9. C. sp. 9 can hybridize with C. briggsae in the laboratory [see abstract by Woodruff et al.]. Of the remaining new species, C. sp. 7 branches off between C. elegans and C. japonica. This species is easier to cultivate than C. japonica and may be a better candidate for comparative experimental work. Two of the new species branch off before C. japonica as sister species of C. sp. 3 and C. drosophilae+C. sp. 2, respectively. Only one of the new species, C. sp. 11, is hermaphroditic. The position of C. sp. 11 in the phylogeny suggests that hermaphroditism evolved three times within the Elegans group. Two of the new species were isolated from rotting leaves and flowers, and five from rotting fruit. Rotting fruit is also the habitat in which C. elegans has been found to proliferate (Barriere and Felix, Genetics 2007) and from which C. briggsae, C. brenneri and C. remanei were repeatedly isolated. This suggests that the habitat of the stem species of Caenorhabditis after the divergence of the earliest branches (C. plicata, C. sonorae and C. sp. 1) was rotting fruit. The rate of discovery of new Caenorhabditis species has steadily increased since the description of C. elegans in 1899, with a leap in the last two years. There is no indication that we are even close to knowing all species in this genus.

Schartner, Caitlin M. et al. (2015) International Worm Meeting "X-chromosome evolution: divergence of X-sequence motifs that drive dosage compensation across Caenorhabditis species."

Meyer, Barbara J., Lo, Te-Wen, Schartner, Caitlin M.

[International Worm Meeting, 2015]

Dosage compensation (DC) across Caenorhabditis species exemplifies an essential process that has undergone rapid co-evolution of protein-DNA interactions central to its mechanism. In C. elegans, recruitment elements on X (rex sites) recruit a condensin-like DC complex (DCC) to hermaphrodite X chromosomes to balance gene expression between the sexes. Recruitment assays in vivo showed that C. elegans rex sites do not recruit the DCC of C. briggsae, and vice versa. To understand how DC complexes and X chromosomes evolved to use different X targeting sequences, we compared DCC subunits and binding sites in C. elegans to those in three species of the C. briggsae clade (15-30 MYR diverged): C. briggsae, its close relative C. nigoni (C. sp. 9), and C. tropicalis (C. sp. 11). By raising antibodies and introducing endogenous tags with TALENs or CRISPR/Cas9, we showed that homologs of both SDC-2, the pivotal X targeting factor, and DPY-27, a DCC-specific condensin subunit, bind X chromosomes of XX animals. Although the DCC shares key components across these four species, the binding sites differ. First, ChIP-seq studies in C. briggsae and C. nigoni identified DCC binding sites that are homologous across these close relatives but differ from C. elegans sites in sequence and location. Second, C. elegans sites use motifs enriched on X (MEX and MEXII) to drive DCC binding, but these motifs are not in C. briggsae or C. nigoni DCC sites and are not X-enriched. Third, we found an X-enriched motif at DCC binding sites of C. briggsae and C. nigoni that is not X-enriched in C. elegans. An oligo with the C. briggsae motif recruits the DCC in C. briggsae, but a similar oligo lacking the motif fails to recruit, establishing the importance of the motif. Fourth, another motif was found in C. briggsae and C. nigoni that shares a few nucleotides with MEX, but its functional divergence was shown by C. elegans recruitment assays. Fifth, two endogenous C. briggsae X-chromosome regions with strong C. elegans MEX motifs fail to recruit the C. briggsae DCC, as assayed by ChIP-seq and recruitment assays. None of these DCC motifs is enriched on the C. tropicalis draft X sequence, supporting further binding site divergence within the C. briggsae clade. Ongoing ChIP-seq studies in C. tropicalis will help determine how C. elegans and C. briggsae clade motifs are evolutionarily related. Comparison of DCC targeting mechanisms across these four species allows us to characterize a rarely captured event: the recent co-evolution of a protein complex and its rapidly diverged target sequences across an entire X chromosome.

Kiontke, Karin C. et al. (2009) International Worm Meeting "New Caenorhabditis species: phylogeny and evolution."

Fitch, David H. A., Felix, Marie-Anne, Kiontke, Karin C.

[International Worm Meeting, 2009]

Recently, nine new Caenorhabditis have been discovered, bringing the number of Caenorhabditis species in culture to nineteen, eleven of which are undescribed. To elucidate the relationships of the new species to the five species with sequenced genomes, we have used sequence data from two rRNA genes and several protein-coding genes for reconstructing the phylogenetic tree of Caenorhabditis. Four new species (spp. 5, 9, 10 and 11) group within the so-called Elegans group of Caenorhabditis, with C. elegans being the first branch. Although none of them is the sister species of C. elegans, C. sp. 5 and C. sp. 9 are close relatives of C. briggsae. C. sp. 9 can hybridize with C. briggsae in the laboratory. Of the remaining new species, C. sp. 7 branches off between C. elegans and C. japonica. Three of these species, C. sp. 7, C. sp. 9 and C. sp. 11 have been chosen for genome sequencing. Four further new species branch off before C. japonica within a monophyletic clade which also comprises C. sp. 3 and C. drosophilae. Only one of the new species, C. sp. 11, is hermaphroditic. The position of C. sp. 11 in the phylogeny suggests that hermaphroditism evolved three times within the Elegans group. Two of the new species were isolated from rotting leaves and flowers, and seven from rotting fruit. Rotting fruit is also the habitat in which C. elegans has been found to proliferate (Barriere and Felix, Genetics 2007) and from which C. briggsae, C. brenneri and C. remanei were repeatedly isolated. This suggests that the habitat of the stem species of Caenorhabditis after the divergence of the earliest branches (C. plicata, C. sonorae and C. sp. 1) was rotting fruit. Other characters, like the shape of the stoma and the male tail, introns, susceptibility to RNAi and genome size are being evaluated in the context of the phylogeny. The rate of discovery of new Caenorhabditis species has steadily increased since the description of C. elegans in 1899, with a leap in the last few years. There is no indication that we are even close to knowing all species in this genus.