Smith, Cassandra et al. (2021) International Worm Meeting "Investigating the role of complexin-1 function in dopamine signaling"

Quinde, Jennifer, Toms, Jiah, Smith, Cassandra, Nelms, Brian, Roach, Corey

[International Worm Meeting, 2021]

Dopamine signaling plays a role in regulating motor control across the animal kingdom and has been implicated in many motor movement-related diseases, but the full set of regulatory molecules controlling dopamine release is still not fully described. Through RNA-sequencing, we identified cpx-1 as a gene highly expressed in dopamine neurons. Previous work has suggested that a loss of the complexin protein, CPX-1, is linked to motor movement defects in C. elegans. We hypothesize that disruption of cpx-1 function in dopamine neurons will lead to an excess of extrasynaptic dopamine due to premature synaptic vesicle fusion. In C. elegans, mutations leading to an excess of extrasynaptic dopamine result in a Swimming-Induced Paralysis (SWIP) phenotype, when the nematode paralyzes within minutes compared to tens of minutes in the wild-type worm. We have observed that cpx-1 mutants show a dopamine-related SWIP phenotype similar to dat-1 mutants. To further investigate the specificity of the role of cpx-1 in dopamine neurons we are generating cpx-1;dop-3 double mutants and using a dat-1p::cpx-1 recovery construct to rescue the cpx-1 mutant phenotype. If we observe a rescue of the SWIP phenotype in the cpx-1;dop-3 double mutants and dat-1p::cpx-1 transgenic worms, then this will suggest cpx-1 function is crucial for proper dopamine neuron function. This work is supported by NSF CREST Center for Biological Signatures & Sensing (#HRD1547757) and NIH R25 Bridges to the Biomedical Doctorate (#2R25GM107754-06A1).

Androwski, Rebecca et al. (2019) International Worm Meeting "Dauer IL2 neurons use distinct and shared mechanisms with FLP and PVDs to regulate arborization."

Androwski, Rebecca, Goelzer, Janet, Hofer, Allison, Smith, Cassandra, Schroeder, Nathan

[International Worm Meeting, 2019]

Environmental stress can significantly influence the shape of dendrites and dendrite morphology plays a key role in proper neural signaling. We aimed to determine the underlying molecules that regulate stress-induced dendritic arborization. When C. elegans are grown under well-fed conditions, the two FLP neurons located in the head begin to arborize rapidly during L4, these arbors persist through adulthood. During the stress-induced dauer stage, four quadrant IL2 neurons arborize similarly to the FLPs, extending arbors out to the body wall and covering the head of the worm. We observed that the FLPs maintain an unbranched state during dauer. Using a forward genetic screen, we identified the membrane-bound receptor DMA-1, which was previously shown to regulate FLP branching, as essential for dauer-specific IL2 arborization. We found that the IL2s use identical DMA-1 binding partners during IL2 dauer arborization. In adult animals a DMA-1::GFP translational reporter clearly localizes to the FLP. Using this same reporter, we observed DMA-1 localization in the IL2 dendrite during dauer, though not during other developmental stages. However, overexpression in the IL2s did not induce branching, suggesting that additional dauer-specific components regulate IL2 arborization during dauer and that the IL2s are inhibited from branching in the adult animal. Intracellularly, DMA-1 enables actin polymerization through interactions with the HPO-30 and TIAM-1. Our mutant analysis shows that HPO-30 and TIAM-1 are necessary for IL2 arborization. While the DMA-1 complex is needed we've found that several of the regulators of the complex in FLP/PVD are dispensable in the IL2s. For example, the unfolded protein response protein IRE-1 is required for proper DMA-1 localization in the PVD/FLPs but is dispensable in dauer IL2s. However, the FOXO transcription factor, DAF-16 can compensate for a blocked UPR. We found that daf-16; daf-7 partial dauers are defective for IL2 arborization while the FLPs remain unaffected. Altogether our results show that DMA-1 functions during dauer to mediate stress-induced dendrite plasticity in the IL2 neurons. The role of DMA-1 during dauer mirrors its function in the adult FLPs. Both extracellular and intracellular DMA-1 binding partners are necessary for IL2 arborization. However, DMA-1 is regulated uniquely during dauer.

Rosenberg R (1978) Worm Breeder's Gazette

Rosenberg R

[Worm Breeder's Gazette, 1978]

All eyes are on the newest fashion trend, the Dumpy Look . Pace setting designer I.M. Worm s androgynous wardrobe is all the rage in Paris. Bianca Jagger quips, Tres, tres - Women s Wear Daily writes, Elegans personified - Patti Smith thinks, The punks won t buy it and Craig Russell says, It fits right in with my act . A product of Mutant Isolation, Inc.

Kravtsov, V. et al. (2013) International Worm Meeting "The effects of aging on dendritic plasticity and PVD-FLP branch coexistence."

Podbilewicz, B., Oren-Suissa, M., Kravtsov, V.

[International Worm Meeting, 2013]

Self-avoidance, tiling and coexistence are the main mechanisms that enable the best dendritic coverage. C. elegans undergoes aging-associated changes that ultimately lead to decreased functionality of the organism, including its neurological functions. Recent research has shown that the nervous system of C. elegans undergoes changes and alterations during aging including dendritic morphology (Tank et al., 2011). We study dendritic plasticity, aging and spatial dendritic organization of two highly arborized mechanoreceptors in C. elegans, PVD and FLP (Oren-Suissa et al., 2010). PVD dendrites of L4s and young adults show regenerative ability following dendrotomy (laser induced severing of dendrites). Our working hypothesis is that in older ages this ability to regenerate is compromised. Previous studies and our preliminary results indicate that PVD and FLP do not overlap in larval stages (Smith et al., 2010). In addition, dendrites within each bilateral PVD do not overlap through a self-avoidance mechanism (Smith et al., 2012). We found that (1) the coverage fields of the PVD and FLP overlap in adult worms, which indicates coexistence and not tiling. This overlap increases as the worm ages. (2) PVDs show aberrant arborization at the age of 9 days of adulthood. (3) Dramatic increase in self-avoidance defects as animals age. In humans many neurodegenerative diseases as well as generalized cognitive decline are associated with age, aberrant arborization or both (e.g. autism and Alzheimer's disease). However our understanding of how these disorders are triggered and aggravated is scarce. Our research provides an insight into the aging and regeneration process of individual neurons. Oren-Suissa, M., et al. (2010). Science 328, 1285-1288. Smith, C.J. et al. (2010). Developmental Biology 345, 18-33. Smith, C.J., et al. (2012). Nature Neuroscience 15, 731-737. Tank, E.M.H. et al. (2011). Journal of Neuroscience 31, 9279-9288.

Cassada RC et al. (1980) Worm Breeder's Gazette "initial characterization of ts embryonic defective (emb) mutants (Goettingen set)."

Culotti MR, Cassada RC, Von Ehrenstein G, Isnenghi E

[Worm Breeder's Gazette, 1980]

[See Figure 1] Already published allelism: Wood et al., 1980: b117=b189; b246 = let- 2.Miwa et al., 1980: hc57 = hc62; hc61 = hc67. Our global complementation results: g1 = g4; g16 = g65 = hc61 = hc67; g36 = hc65; g23 = g34 = hc70 = b117 = b189; g37 = b246 = let-2; b84 = hc66; g14 = g43; g57 = b1O. From frequency of multiple alleles we estimate 200-400 genes essential for embryogenesis. Mapping is in progress. We are also doing tsp's, R + H Tests, and cellular defects ( Isnenghi, Cassada, Radnia, Schierenberg, K. Smith, v. Ehrenstein).

Pourkarimi, Ehsan et al. (2015) International Worm Meeting "Epigenetic program of DNA replication."

Whitehouse, Iestyn, Pourkarimi, Ehsan, Bellush, James

[International Worm Meeting, 2015]

In eukaryotes, multiple replication origins initiate DNA synthesis bidirectionally. Half of the genome is duplicated discontinuously on the lagging strand in the form of Okazaki Fragments (OFs). Previously we have purified and sequenced OFs from S. cerevisiae, and have demonstrated their utility in mapping genome wide DNA replication patterns (1,2). Despite many years of research, the precise location efficiency and abundance of replication origins in metazoa remains elusive. Here we capture and sequence OFs from C. elegans and generate a genome wide map of DNA replication.We use a DNA ligation compromised genetic background and purify single stranded OFs from developing embryos. Aligning sequence reads of OFs to the C. elegans genome reveals a characteristic strand bias at specific sites that are approximately 50-100 Kb apart. The complementary enrichment of Okazaki fragments to either the Watson or Crick strands is the hallmark of a replication origin. Additionally we have found that origins of replication in C. elegans are correlated with transcriptionally active regions of chromatin. Using the histone modification data set of modENCODE we found a strong association between replication start sites and acetylation of Histone H3 lysine 27 (H3K27ac). Acetylation of H3K27 is a chromatin mark characteristic of gene enhancer elements. Finally, we show that a partial depletion of CBP/P300 the sole histone H3 acetyltransferase (HAT) responsible for H3K27 acetylation has a profound effect on DNA replication. Our data indicate that the DNA replication program is likely plastic and is matched with the transcriptional program. Ultimately our data show, both DNA replication and gene transcription are likely regulated by similar epigenetic processes. 1. Intrinsic coupling of lagging-strand synthesis to chromatin assemblyDuncan J. Smith& Iestyn Whitehouse. Nature, 20122. Quantitative, genome-wide analysis of eukaryotic replication initiation and termination.McGuffee SR, Smith DJ, Whitehouse I. Mol Cell, 2013.

Bo S et al. (2019) J Theor Biol "Potential relations between post-spliced introns and mature mRNAs in the Caenorhabditis elegans genome."

Zhao X, Li H, Bao T, Zhang Q, Lu Z, Bo S

[J Theor Biol, 2019]

There are potential interactions between introns and their corresponding coding sequences (CDSs) in ribosomal protein genes that have been proposed by our group and the interactions are achieved by sequence matches between the two kinds of sequences. Here, the optimal matching relations between mature mRNAs and their corresponding introns in Caenorhabditis elegans (C.elegans) were investigated by improved Smith-Waterman local alignment software. Our results showed that the remarkably matched regions appear in the untranslated regions (UTRs) of mRNAs, especially in the 3' UTR. The optimal matched segments (OMSs) are highly organized segments. In addition, the optimal matching relations were analysed between mature mRNAs and other introns. The matching strengths in the UTRs are clearly lower than those in their corresponding introns. Our studies indicate that there are potential interactions between mature mRNAs and their corresponding introns and the post-spliced introns should have other novel functions in the gene expression process.

Cohn DH et al. (2003) Am J Hum Genet "Mental retardation and abnormal skeletal development (Dyggve-Melchior-Clausen dysplasia) due to mutations in a novel, evolutionarily conserved gene."

Ehtesham N, Shanske A, Cohn DH, Krakow D, Powell BR, Rimoin DL, Unger S, Reinker K

[Am J Hum Genet, 2003]

Dyggve-Melchior-Clausen dysplasia (DMC) and Smith-McCort dysplasia (SMC) are similar, rare autosomal recessive osteochondrodysplasias. The radiographic features and cartilage histology in DMC and SMC are identical. However, patients with DMC exhibit significant developmental delay and mental retardation, the major features that distinguish the two conditions. Linkage studies localized the SMC and DMC disease genes to chromosome 18q12-21.1, providing evidence suggesting that they are allelic disorders. Sequence analysis of the coding exons of the FLJ90130 gene, a highly evolutionarily conserved gene within the recombination interval defined in the linkage study, identified mutations in SMC and DMC patients. The affected individuals in two consanguinous DMC families were homozygous for a stop codon mutation and a frameshift mutation, respectively, demonstrating that DMC represents the FLJ90130-null phenotype. The data confirm the hypothesis that SMC and DMC are allelic disorders and identify a gene necessary for normal skeletal development and brain function.

Lee DG et al. (1997) International C. elegans Meeting "THE EXPRESSION PATTERN OF CALETICULIN, A HIGH AFFINITY CALCIUM BINDING PROTEIN"

Ahnn JH, Lee DG

[International C. elegans Meeting, 1997]

In C. elegans, a homologue of mammalian calreticulins was cloned and sequenced (M. Smith, DNA seq. 2: 235-40). This gene is composed of three exons and two introns and encodes a protein of 395 amino acid residues including an N-terminal signal sequence. The C-terminus contains an ER retention signal HDEL preceded by a polyacidic region similar to the mammalian calreticulins. Especially, the sequence displays 61% homology to mouse calreticulin, increasing up to 82% in the proline-rich region. This gene was designated as crt-1 and mapped to the left end of chromosome V of the physical map. To observe the expression pattern of calreticulin in some tissues of C. elegans, we are currently constructing a genomic clone fused with GFP reporter, which will be injected into an animal to obtain transgenic lines. At the same time, a cDNA clone obtained by PCR will be used for over expression in E. coli to produce antibodies.

Boateng R et al. (2018) Genetics "New Role for an Old Protein: An Educational Primer for Use with "The Identification of a Novel Mutant Allele of topoisomerase II in Caenorhabditis elegans Reveals a Unique Role in Chromosome Segregation During Spermatogenesis"."

Allen AK, Boateng R

[Genetics, 2018]

Modern experimental techniques, such as whole-genome sequencing and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 endogenous genome editing, are enabling researchers to identify and further characterize the roles of proteins that were previously thought of as well defined. In the December 2016 issue of GENETICS, an article by Jaramillo-Lambert et al. identified a new role for the enzyme topoisomerase II in Caenorhabditis elegans male meiosis. This Primer article is designed to provide essential background information on C. elegans spermatogenesis and the relevant scientific techniques that will assist students and instructors in their understanding and discussion of the related article.Related article in GENETICS: Jaramillo-Lambert, A., A. S. Fabritius A. S., T. J. Hansen T. J., H. E. Smith H. E., and A. Golden A., 2016The identification of a novel mutant allele of topoisomerase II in Caenorhabditis elegans reveals a unique role in chromosome segregation during spermatogenesis. Genetics204: 1407-1422.