Mueller, Katherine et al. (2015) International Worm Meeting "Activation of Target Gene Expression in Neurons by the RFX Transcription Factor DAF-19."

Swoboda, Peter, Sugiaman-Trapman, Debora, De Stasio, Elizabeth A., Phirke, Prasad, Mueller, Katherine

[International Worm Meeting, 2015]

DAF-19, the only RFX transcription factor found in C. elegans, is required for the formation of neuronal sensory cilia. Four isoforms of the DAF-19 protein have been reported, and the daf-19(m86) nonsense mutation affecting all four isoforms has been shown to prevent cilia formation. Transcriptome analyses employing microarrays of L1 or adult stage worms were completed using RNA from daf-19(m86) worms and an isogenic wild type strain to identify potential additional DAF-19 target genes. Using transcriptional fusions with GFP, we compared the expression patterns of several potential target genes using fluorescence confocal microscopy. Our data indicate that at least three new genes are activated by DAF-19 in both ciliated and non-ciliated sensory neurons. One gene is activated in IL2 neurons, a class of ciliated sensory neurons while two genes are activated by DAF-19 in the URX neuron. URX is through to be important for aerotaxis, lifespan regulation, and suppression of innate immunity. These results suggest a role for DAF-19 beyond that of ciliogenesis. We are currently exploring whether expression of these target genes is dependent on a particular isoform of DAF-19.

You-Chan Kim et al. (2001) International C. elegans Meeting "Coaction of DNA topoisomerase IIIalpha and RecQ homologue during the germline mitosis in Caenorhabditis elegans"

You-Chan Kim, Hyeon-Sook Koo, Min-Ho Lee

[International C. elegans Meeting, 2001]

DNA topoisomerase III can interact with RecQ family DNA helicases functionally and physically in eukaryotic cells, contributing to genome stability. Among four RecQ homologues predicted from the Caenorhabditis elegans genomic DNA sequence, T04A11.6 is the most similar to Bloom syndrome!-s protein in humans. To investigate a possible interaction of the protein with topoisomerase III a (Top3 a ), as observed between Top3 and RecQ homologues in yeast and human, the top3 a gene expression was suppressed by RNA interference in a C. elegans mutant, him-6 ( e1104 ) with an amino acid substitution in the RecQ homologue, T04A11.6(communicated by Drs. F. Mueller and C. Wicky). Germ cells in the gonads of the progeny showed severe chromosomal abnormalities and were arrested during mitosis with a subsequent failure of entering meiosis. These phenotypes were also observed in the progeny produced by double RNA interference of the top3 a and recQ gene expression, though at a reduced level. The severe phenotypes resulting from the double deficiency of top3 a and recQ contrasted with the results in yeast, where a recQ mutation suppressed some phenotypes of top3 null mutation. Therefore, in C. elegans, Top3 a and the RecQ homologue (T04A11.6) act either together in a complex or separately in two redundant pathways, which contribute to genome stability during germline mitosis.

Driscoll MA et al. (2000) East Coast Worm Meeting "Contributions of WRN-related Helicases to C. elegans Aging"

Nycz KM, Herndon LA, Driscoll MA

[East Coast Worm Meeting, 2000]

Four genes in the C. elegans genome exhibit sequence similarity to the RecQ family of DNA helicases which include the human Werner (WRN), Bloom (BLM) and Rothmund-Thomson (RTS) syndrome genes. Mutation of human WRN and RTS can confer features of accelerated aging. Both WRN and RTS patients have a high rate of genome instability, which is also a key feature of patients with Bloom syndrome. Similarly, mutation of the yeast RecQ homolog, SGS1, results in a high rate of genomic instability and a lifespan 40% shorter than wild type1, 2. To determine if the RecQ family of helicases share similar functions in C. elegans, we generated deletions within the C. elegans gene most closely related to the Werners gene (F18C5.2) and in another homolog (E03A3.2) and have tested these strains for lifespan and genomic instability. Preliminary results indicate that animals lacking F18C5.2 or E03A3.2 are viable and fertile. They have normal lifespans and do not have a high rate of genomic instability. Since C. elegans has four related helicases, there may be redundancy in the activity of these helicases. To test this hypothesis, we are now analyzing animals that carry mutations in multiple DNA helicase family members. It has recently been determined that him-6 mutant animals, which have a high rate of chromosome nondisjunction, contain mutations in the C. elegans DNA helicase gene T04A11.6, which is most closely related to the human BLM gene3. We are also testing mutants for UV radiation or X-ray hypersensitivity, since it is possible that these helicases play a role in DNA repair. We are testing the expression pattern of these genes and are screening for a deletion in the fourth remaining C. elegans DNA helicase family member, K02F3.1. By establishing a nematode model for accelerated aging disorders, we hope to extend understanding of the action of helicase family members in senescence and learn more about mechanisms of aging overall. Watt, P.M., I.D. Hickson, R.H. Borts and E.J. Louis. 1996. Genetics 144: 935. Sinclair, D.A., K. Mills and L. Guarente. 1997. Science 277: 1313. Wicky, C., A. Rose and F. Mueller. 1998. European Worm Meeting Abstract.

LA Herndon et al. (1999) International C. elegans Meeting "Contributions of degenerative cell death and a WRN-related helicase to C.elegans aging"

LA Herndon, M Driscoll

[International C. elegans Meeting, 1999]

Cell death is a highly regulated process that plays important roles in normal development and in response to cellular injury. Whether injury-induced cell death, also known as necrosis, contributes in a critical way to the aging of an organism is unknown. Since aging worms exhibit many vacuolar structures that look similar to degenerative cell deaths (for example, as induced by mec-4(d) mutations), we wondered about a possible relationship between necrotic-like cell death and aging. We identified genes required for degenerative cell death, called des genes ( de generation s uppressors), by screening for mutations that block necrosis. We hypothesized that if these mutations also suppress aging-associated vacuolation and if degenerative cell death plays a critical role in C. elegans aging, the des mutants might have extended lifespans or exhibit increased vitality late in life. We show that animals mutant in one gene, identified by alleles bz29 and bz30 , have an extended lifespan. We are characterizing these lines to determine extent of random vacuole formation, general locomotor activity, resistance to heat and oxidative stresses, and interaction with the dauer formation mutants that are known to affect the lifespan of adult animals. In another line of experimentation, we are attempting to identify mutations that may accelerate senescence in C. elegans . Mutations in the human Werner's syndrome helicase (WRN) and in the related yeast SGS1 helicase produce features of accelerated aging. There are four C. elegans genes that exhibit sequence similarity to the RecQ family of DNA helicases. We have generated a deletion within the C. elegans gene most similar to the Werner's gene (F18C5.2). Preliminary results indicate that these animals appear to have a normal lifespan and genetic stability. As there may be redundancy in the activity of these helicases, we are currently characterizing animals carrying both the Cewrn deletion and a mutation in another helicase family member, him-6 1 . We are screening for deletions in the other two C. elegans DNA helicase family members. Establishment of a nematode model for accelerated aging disorders should extend understanding of the action of helicase family members in senescence. 1. Wicky, C., A. Rose and F. Mueller. 1998. European Worm Meeting Abstract.

Sternberg, Paul et al. (2015) International Worm Meeting "WormBase 2015."

Howe, Kevin, Harris, Todd, Stein, Lincoln, Kersey, Paul, Berriman, Matt, Schedl, Tim, Sternberg, Paul

[International Worm Meeting, 2015]

WormBase has existed for 15 years and has evolved in many ways. The new website is fully operational and has made the process of adding new data types, displays, and tools easier. Behind the scenes we are piloting an overhaul of the underlying database infrastructure to allow us to handle the ever increasing data, have the website perform faster, and allow more frequent updates of information. This is a critical time for the project, as we face considerable pressure from two directions. The first is that our funders really want us to do more with less. We are responding to this by leading the way in making curation (the process of extracting information from papers and data sets into computable form) more efficient using a new version of Textpresso (to be released later this calendar year); by discussing with other model organism information resources ways to work together to be more efficient and inter-connected; and by seeking additional sources of funding. The second, delightful, pressure is an increase in data and results generated by the C. elegans and nematode communities. While we are handling this increase by changes in our software for curation, the database infrastructure, and the website, we do need your help. Many of you have helped us over the last few years to identify data in your papers or by sending us data directly. We now need you to help with a few types of information by submitting the data via specially designed, user-friendly forms that ensure good quality and the use of standard terminology. In particular, we have a large backlog of uncurated information associating alleles with phenotypes. We pledge to make this process as painless as possible, and to improve WormBase's description of phenotypes with your feedback, starting at this meeting at the WormBase booth, workshops and posters. With your help, continual improvement of our efficiency, and additional sources of funding, we are optimistic that we can do much more with even somewhat less effort.Consortium: Paul Davis, Michael Paulini, Gary Williams, Bruce Bolt, Thomas Down, Jane Lomax, Todd Harris, Sibyl Gao, Scott Cain, Xiaodong Wang, Karen Yook, Juancarlos Chan, Wen Chen, Chris Grove, Mary Ann Tuli, Kimberly Van Auken, D. Wang, Ranjana Kishore, Raymond Lee, John DeModena, James Done, Yuling Li, H.-M. Mueller, Cecilia Nakamura, Daniela Raciti, Gary Schindelman.

Magnenat L et al. (1996) European Worm Meeting "TELOMERASE-MEDIATED CHROMOSOME HEALING IN NEMATODES"

Mueller F, Tobler H, Jentsch S, Magnenat L

[European Worm Meeting, 1996]

Telomeres are specialized terminal structures, that are necessary for the stability and complete replication of linear chromosomes. In most eukaryotic organisms, synthesis and maintenance of telomeric DNA sequences require a specialized telomere terminal transferase activity (telomerase). If the protecting extremities are lost during a chromosome fragmentation event, new telomere formation at the broken ends is essential to prevent genome rearrangements (reviewed in Telomeres, Blackburn & Greider, 1995). In nematodes, which have TTAGGC telomeric repeats similar to those of other eukaryotes, two interesting types of healing events have been reported: 1) An example of spontaneous chromosomal healing has been described for the Caenorhabditis elegans X-chromosome mutation me8, which disrupts meiotic crossing over and segregation. Molecular analysis of the me8 mutation revealed that it is a terminal chromosomal truncation healed by the de novo addition of telomeric repeats directly to the site of breakage. (C. Wicky et al., 1996. PNAS: in press ). 2) During the somatic differentiation of Ascaris suum, the developmentally-programmed phenomenon of chromatin diminution consists of chromosomal cleavage at specific breakage regions (CBRs), chromosome healing by new telomere formation and degradation of the eliminated chromatin. (F. Mueller et al., 1991. Cell 67: 815-822). Chromosome healing in both nematodes share the same molecular characteristics. First, the telomere addition sites share no sequence homology or secondary structures with each other. Second, no pre-existing telomeric sequences are found within CBRs, and third, all junctions contain 1-4 ambiguous bases which can be used as telomerase initiation primers. However, spontaneous chromosomal healing in C. elegans takes place randomly in germ cells with low efficiency, whereas the developmentally-programmed healing in A. suum is highly efficient and occurs in all presomatic cells. Also, a random distribution of the telomere addition sites within the CBRs suggests that chromatin diminution is initiated with a double-strand DNA break which is followed by exonuclease trimming of the unprotected ends until the telomerase- mediated healing machinery encounters the appropriate conditions to add new telomeric sequences. Surprisingly, telomeric repeats are not only added to the ends of the truncated chromosomes, but also to the eliminated chromatin fragments. This suggest that in A. suum, the same telomerase activity that is responsible for telomere maintenance and spontaneous healing may have been adapted to catalyze the highly efficient programmed healing process during chromatin diminution. To further analyze telomerase-mediated chromosome healing, we developed an in vitro telomerase system for both nematode species. Since we observed a DNA polymerization activity producing repeats of 6 bases that was sensitive to heat inactivation, proteinase K and RNase A digestions in the Ascaris cell-free extracts, we concluded that it represents telomerase activity. Its presence during early developmental stages may indicate a role for telomerase in the mechanism of chromatin diminution. Currently, different C. elegans extracts are being tested for telomerase in vitro and preliminary results suggest the presence of a similar activity. Given the abundance of the genetic tools and the advanced state of the physical and genetic map of the C. elegans genome, as well as the biochemical potential of A. suum, nematodes may serve as excellent model systems for the analysis of the telomere and telomerase function during chromosome healing processes among metazoan organisms.