Zetka M-C et al. (1993) Worm Breeder's Gazette "Mapping of the rec-1 Mutation"

Rose AM, Zetka M-C

[Worm Breeder's Gazette, 1993]

MAPPING OF THE rec-1 MUTATION Monique-Claire Zetka and Ann M. Rose, Dept. of Medical Genetics, 6174 University Blvd., University of British Columbia, Vancouver, B.C., V6T lZ3.

Rankin, Aysha C. et al. (2015) International Worm Meeting "Genes involved in embryonic motor neuron positioning along the AP axis."

Tanner, Matthew, Slatculescu, Cristina, Robinson, Claire, Rankin, Aysha C., Colavita, Antonio, Perkins, Theodore

[International Worm Meeting, 2015]

The six embryonically-derived DD motor neurons are born evenly spaced along the AP axis in newly hatched larvae and maintain this spacing into adulthood. We have found that components of a planar cell polarity (PCP)-like pathway that includes prkl-1/Prickle and vang-1/Van Gogh are important for properly positioning DD motor neurons in the ventral nerve cord. In prkl-1, and to a lesser extent, vang-1 mutants, DD neurons are shifted anteriorly and display distinctive cell spacing defects. These defects can be rescued by prkl-1 or vang-1 expression from a pan-neuronal promoter suggesting cell-autonomous roles. DA and DB neurons are also mispositioned in prkl-1 and vang-1 mutants. Neuronal positioning defects are present in newly hatched larvae suggesting an embryonic origin for the defect. DD1,3,5 and DD2,4,5, derived from left and right sides of the embryo, undergo cell intercalation during the comma stage to form a single line of DD neurons at the midline. prkl-1 and vang-1 mutants display DD intercalation defects that are suggestive of a delay in cell intercalation or improper cell-cell neighbor interactions during intercalation. In order to identify new genes involved in cell intercalation and the proper positioning of motor neurons along the AP axis as well as new insight into PCP-like signaling we are in the process of performing a forward genetic screen for DD neuron spacing defects. PCP signaling is known to play an important role in cell intercalation during neural tube and organ morphogenesis in vertebrates. Our findings show for the first time that a PCP-like pathway involving the core components Prickle and Van Gogh is involved in some aspects of cell intercalation during C. elegans development.

Robinson-Thiewes, Sarah et al. (2021) MicroPubl Biol

Kimble, Judith, Robinson-Thiewes, Sarah

[MicroPubl Biol, 2021]

Most eukaryotic genes make nascent transcripts that include both introns and exons. Introns are spliced out, usually co-transcriptionally, to generate mature mRNA (Herzel et al. 2017). Once considered a byproduct of transcription, introns are now known to affect virtually all aspects of mRNA metabolism, from transcriptional initiation to translation (Swinburne and Silver 2008; Chorev and Carmel 2012; Rose 2019). Genes can have multiple introns of variable size, but the first intron is often the longest (Smith 1988; Kriventseva and Gelfand 1999; Bradnam and Korf 2008). We wondered if the long first intron of a critical developmental regulator might affect its expression during development. To address this question, we analyzed expression of the C. elegans mpk-1b RNA, which encodes a nematode ERK/MAPK ortholog and has a long first intron (Figure 1A). Because mpk-1b is a germline-specific RNA (Lee et al. 2007; Robinson-Thiewes et al. 2020a), we assayed its expression along the developmental axis of the distal gonad (Figure 1B). Here, germ cells move through three regions as they progress from germline stem cells (GSCs) to differentiation: GSCs and GSC daughters primed for differentiation reside in the Progenitor Zone (PZ); germ cells enter meiotic prophase in the Transition Zone (TZ); and continue through meiotic prophase in the Early Pachytene (EP) region (Figure 1B)(Hubbard and Schedl 2019). Previously, we reported that a set of three ~1 kb deletions at distinct sites within the mpk-1b long intron did not affect its transcription or mRNA abundance (Robinson-Thiewes et al. 2020b). Here, we report effects of these deletions on production of the MPK-1B protein.

Sym M et al. (2000) West Coast Worm Meeting "Two new genes regulating neuroblast migration in C. elegans"

Kenyon CJ, Yang L, Sym M, Ch'ng Q-L

[West Coast Worm Meeting, 2000]

In C. elegans, the Q cells are bilaterally symmetric neuroblasts present in the posterior body region of the worm at hatching. During the first larval stage, the Q cells divide and migrate. QR and its descendents migrate anteriorly whereas QL and its descendents migrate posteriorly. Several genes that regulate the anterior migrations of QR and its descendents have been identified. These include: 1) lin-39, a homeobox gene required in QR and its descendents for migration (Wang B. et al, 1993; Clark S. et al, 1993); 2) mig-13, a novel transmembrane protein required outside of QR and its descendents for migration (Sym M et al, 1999); and 3) egl-20, a Wnt homolog expressed in cells in the tail region (Whangbo J.. and Kenyon C, 1999). Two mutant screens (Mary Sym and Queelim Ch'ng) were conducted to identify additional genes that regulate the migration of QR and its descendents. From these screens, mutations in two new genes were identified that cause certain cells in the QR lineage to stop migrating prematurely. These two genes seem likely to be involved in guidance rather than in providing cells with the ability to migrate because, in these mutants, other cells sometimes migrate in the wrong direction. Current efforts are directed toward cloning these two genes and determining how these genes regulate the migration of QR and its descendents together with genes previously known to regulate these migrations. References: Clark SG, Chisholm AD, and Horvitz HR. 1993. Control of Cell Fates in the Central Body Region of C. elegans by the Homeobox Gene lin-39. Cell 74: 43-55. Sym M, Robinson N, Kenyon C. 1999. mig-13 Positions Migrating Cells Along Anteroposterior Body Axis of C. elegans. Cell 98: 26-36. Wang BB, Muller-Immergluck MM, Austin, J, Robinson, NT, Chisholm, A, Kenyon, C. A Homeotic Gene Cluster Patterns the Anteroposterior Body Axis of C.. elegans. Cell 74: 29-42. Whangbo J, Kenyon, C. A Wnt Signaling System that Specifies Two Patterns of Cell Migration in C. elegans. Molecular Cell 4: 851-858.

WB Derry et al. (1999) International C. elegans Meeting "Analysis of the C. elegans homolog of the FHIT tumor suppressor gene"

WB Derry, S van Kreeveld, JH Rothman

[International C. elegans Meeting, 1999]

Alterations in the FHIT gene occur frequently in the development of several human cancers (1). The Fhit protein is a diadenosine P 1 , P 3 -triphosphate hydrolase and is a member of the histidine triad superfamily of nucleotide binding proteins (2). The cellular mechanism of Fhit activity and the relationship between Fhit signaling and tumorigenesis are presently unknown. The C. elegans and Drosophila FHIT genes encode a fusion protein in which the Fhit domain is fused with a novel domain showing homology to bacterial and plant nitrilases, and are referred to as NitFhit (3). We are interested in understanding the role of NitFhit in development and programmed cell death. RNAi of C. elegans NitFhit causes an embryonic arrest phenotype, suggesting an essential role for this gene in development. We are currently analyzing the loss-of-function phenotype and the effect of ectopic NitFhit expression on viability and programmed cell death in the worm. (1) Huebner, K., Garrison, P.N., Barnes, L.D. & Croce, C.M. (1998). Ann. Rev. Genet ., 32 : 7-31. (2) Barnes, L.D., Garrison, P.N., Siprashvili, Z., Guranowski, A, Robinson, A.K., Ingram, S.W., Croce, C.M., Ohta, M. & Huebner, K. (1996). Biochemistry , 35 : 11529-11535. (3) Pekarsky, Y., Campiglio, M., Siprashvili, Z, Druck, T., Sedkov, Y, Tillib, S., Draganescu, A., Wermuth, P., Rothman, J.H., Huebner, K., Buchberg, A.M., Mazo, A., Brenner, C. & Croce, C.M. (1998). Proc. Natl. Acad. Sci. USA , 95 : 8744-8749.

Kenyon CJ et al. (2000) West Coast Worm Meeting "How are anterior cell migrations guided by mig-13?"

Kenyon CJ, Ch'ng Q-L

[West Coast Worm Meeting, 2000]

mig-13 was previously identified as a guidance factor specifically required for the anterior migrations of the QR descendants. mig-13 acts by promoting cell migrations in the anterior direction (Sym et. al., 1999). We are taking several approaches to understand further how the anterior migrations of the QR descendants are guided by mig-13. mig-13 is predicted to encode a novel transmembrane protein containing a CUB domain and LDL-receptor repeat in the extracellular region as well as a proline-rich domain in the intracellular region (Sym et. al., 1999). Our structure/function studies suggest that the extracellular domain of MIG-13 alone can confer partial function in guiding the QR descendants to the anterior. A rescuing mig-13::GFP fusion was previously found to be expressed in the anterior and mid-body ventral cord motor neurons, which cross the migratory track of the QR descendants. Consistent with this expression pattern, mosaic analysis revealed that mig-13 acts non-autonomously to direct the migrations of the QR lineage (Sym et. al., 1999). To determine where mig-13 expression is sufficient to guide the migrating cells, we are expressing mig-13 in broad sets of tissues, as well as in specific subsets of cells that express mig-13::GFP. We also intend to refine previous mosaic analysis to pinpoint the cells in which mig-13 acts. Reference Sym M, Robinson N and Kenyon C. Cell, 1999 Jul 9, 98(1):25-36.

Claire Lecroisey et al. (2006) European Worm Meeting "Implication of the Dense Body Protein Dyc-1 in the Dystrophin Dependent Muscle Degeneration"

Kathrin Gieseler, Laurent Segalat, Claire Lecroisey

[European Worm Meeting, 2006]

Claire Lecroisey, Kathrin Gieseler and Laurent Sgalat. The molecular mechanism underlying muscle necrosis in dystrophinopathies remains elusive. Our group addresses this question by using the genetically amenable animal model Caenorhabditis elegans, which has the same overall sarcomere composition and architecture as those of vertebrates.. In C. elegans, mutation of the dystrophin homologue, dys-1(cx18), produces a peculiar behavioural phenotype (hyperactivity, a tendency to hypercontract). In a sensitized hlh-1(cc561ts) background, which is a mild mutation of the myogenic factor MyoD, the dys-1(cx18) mutation also leads to a progressive muscle necrosis. The dyc-1 gene was previously identified in a genetic screen because its mutation leads to a phenotype similar to that of dys-1(cx18) mutation, which suggests that the two genes are functionally linked. Like dys-1(cx18); hlh-1(cc561ts), the double mutant dyc-1(cx32); hlh-1(cc561ts) also shows a progressive muscle degeneration. Moreover, Dyc-1 overexpression partially suppresses the dys-1(cx18); hlh-1(cc561ts) phenotype.. In the sarcomere, Dyc-1 is localized at the edge of the dense body, the nematode muscle adhesion structure functionally equivalent to vertebrate Z disc, where actin filaments are anchored. Two hybrid and immunocytochemistry experiments indicate that Dyc-1, Deb-1 (the vinculin homologue and main component of dense bodies), Zyx-1 (a focal adhesion protein), and Atn-1 (alpha-actinin homologue) may form a complex at the dense body. Our results suggest that the dense body might be the site of early pathological events occurring in the absence of dystrophin.. We are currently trying to demonstrate that dystrophin impairs the function of dense bodies proteins.

Yung S Lie et al. (2003) International Worm Meeting "Identification of proteins interacting with MIG-13 in Q cell migration"

Jean-Francois Rual, Marc Vidal, Cynthia Kenyon, John R Yates, Scott Anderson, Mary E Hatten, Yung S Lie

[International Worm Meeting, 2003]

We are studying cell migration in the context of anteroposterior migrations of the Q neuroblasts and their descendants. QR and QL are born in right-left symmetrical positions in the animal. QR and its descendants migrate towards the anterior of the body, while QL and its descendants migrate towards the posterior. Proper positioning of QR and its descendants in the anterior requires mig-13. mig-13 encodes a novel transmembrane protein (Sym et al., 1999). We currently know very little about the mechanism by which MIG-13 functions. In order to learn more about how migrating cells determine a final stopping point, we are performing biochemical experiments to isolate proteins that bind to MIG-13. Immunoprecipitations were performed using extracts from worms expressing a rescuing MIG-13-GFP fusion, or as a control, from worms expressing GFP alone. A commercial anti-GFP antibody was used to isolate the fusion protein (or GFP alone in the control) and any associated proteins.Immunoprecipitated samples were analyzed by mass spectrometry to identify proteins present in each sample. We will present data from this mass spectrometry analysis. RNAi was used to disrupt the gene function of candidates identified by mass spectrometry. One such candidate has a QR descendant cell migration phenotype when disrupted by RNAi. We are investigating the interaction of this candidate with MIG-13 by yeast two hybrid and by other biochemical methods. In addition, we plan to complete genetic analysis to determine the functional significance of these protein-protein interactions. We are also currently characterizing a mutant, mu335, which has a phenotype similar to mig-13. QR descendant cell migration is defective in mu335 animals. We have mapped mu335 to the center of LGIII. To identify the gene disrupted by mu335, we are in the process of injecting cosmids for rescue of the migration phenotype. Sym, M., Robinson, N., and Kenyon, C. (1999). MIG-13 positions migrating cells along the anteroposterior body axis of C. elegans. Cell 98, 25-36.

Judkins, Joshua C. et al. (2011) International Worm Meeting "Second generation synthesis and bioactivity of novel endogenous ligands of the nuclear hormone receptor DAF-12."

Judkins, Joshua C., Mahanti, Parag, Bose, Neelanjan, Schroeder, Frank, Hoffman, Jacob

[International Worm Meeting, 2011]

Nuclear hormone receptors (NHR's) are critical components in metazoan signaling cascades, and it is estimated that 284 NHRs exist in C. elegans.1 Although the function of most NHR's may be regulated by small molecule ligands, endogenous ligands for only one C. elegans NHR have been proposed. The two bile-acid-like steroids, D4- and D7-dafachronic acids were predicted as endogenous transactivators of DAF-122, an NHR with high homology to vertebrate Vitamin D and LXR receptors.3 Recent studies by the Schroeder group have revealed the presence of additional ligands of DAF-12. The structural diversity of the newly revealed dafachronic acids highlights the importance of a high yielding and flexible approach to chemically synthesize DAF-12 ligands for biological investigation. Here we present a novel second generation synthesis that is shorter, more efficient, and more versatile than those previously published.4-8 In addition, our synthesis converges on an aldehyde intermediate that allows divergent access to both previously described and novel dafachronic acids. Our synthetic approach provides D4- and D7-dafachronic acids in 6 and 9 steps, respectively. Key features of this synthesis include multiple transformations in a one-pot reaction and a late-stage chiral hydrogenation. The variety of structures attainable through this synthetic method has allowed us to investigate the role of these and related molecules in C. elegans signaling pathways and to examine structure activity relationships (SAR's) of several dafachronic acid variants. We present bioactivity data for several natural and non-natural dafachronic acids. In addition, we compared SAR's obtained from in-vitro experiments with the results from in-vivo studies. [1] Robinson-Techavi et al.; J. Mol. Evol. 2005, 60, 577. [2] Motola et al.; Cell. 2006, 124, 1209. [3] Antebi et al.; Genes & Dev., 2000, 14, 1512. [4] Giroux et al.; Org. Lett., 2008, 16, 3643. [5] Giroux et al.; Org. Lett., 2008, 5, 801. [6] Giroux et al.; JACS, 2007, 129, 9866. [7] Martin et al.; Org. Biomol. Chem., 2010, 8, 739. [8] Gioiello et al.; Tetrahedron, 2011, 67, 1924.

Albertson DG (1990) Worm Breeder's Gazette "The Mutation mn164 is an X;I Translocation"

Albertson DG

[Worm Breeder's Gazette, 1990]

The mutation mn164 recovered after X-ray treatment promotes X chromosomal nondisjunction when homozygous or heterozygous. The mutation was mapped to the left end of the X chromosome and it was proposed that a structural abnormality was affecting segregation of the X chromosome. Equational nondisjunction of the mn164 bearing chromosome, but not its homolog, was observed in heterozygotes (Herman et al. (1982) Genetics 102, 379-400). As most him mutations show reductional nondisjunction, it was of interest to look at the cytogenetics of a him mutation causing equational nondisjunction. The first meiotic division is reductional in C. elegans, and abnormal bivalents have been seen at diakinesis in some of the him mutants that cause reductional nondisjunction. Thus, in mn164, abnormalities were expected at the second meiotic division. However, abnormal chromosome segregation was seen at both meiotic divisions in embryos from mn164/dpy-3 hermaphrodites, and at diakinesis in these hermaphrodites a large trivalent and four normal-sized bivalents were seen. In mn164 homozygotes a univalent was present in addition to the one large and four normal-sized bivalents. The large bivalent is reminiscent of mnT12(IV,X), suggesting that mn164 is a translocation. In situ hybridization of the ribosomal DNA probe (pCe7) to the middle of the large chromosome identified LGI as one member of the translocation. Hybridization of pCe7 and a probe for the right end of the X (mlc-1,2) to embryonic metaphases showed hybridization at 40-50% from one end of the long chromosome (pCe7) and on the end (mlc-1,2). These observations suggested that mn164 is a translocation involving joining of the left end of X to the right end of LGI. Hybridization of pCe7 to the ribosomal DNA appears reduced and therefore the univalent seen in oocytes of mn164 homozygotes, an extra copy of LGI, may be necessary for viability. Since these cytogenetic observations were made on mn164 animals some time after the original description of the mutation, it was possible that the Cambridge stock had changed from the original. Therefore Claire Kari and Bob Herman thawed a stock of mn164, frozen on January 5, 1981 and pseudolinkage between unc-54(I) and dpy-3(X) was confirmed by mating mn164 males with unc-54(I);dpy-3(X) hermaphrodites.