Kaplan HS et al. (2018) Neuron "Sensorimotor Integration for Decision Making: How the Worm Steers."

Kaplan HS, Zimmer M

[Neuron, 2018]

Animals' movements actively shape their perception and subsequent decision making. In this issue of Neuron, Liu etal. (2018) show how C.elegans nematodes steer toward an odorant: a dedicated interneuron class integrates oscillatory olfactory signals, generated by head swings, with corollary discharge motor signals.

Ali L et al. (2020) J Cell Biol "Mitochondrial translation, dynamics, and lysosomes combine to extend lifespan."

Ali L, Haynes CM

[J Cell Biol, 2020]

In this issue, Liu et al. (2019. J. Cell. Biol.https://doi.org/10.1083/jcb.201907067) find that the inhibition of mitochondrial ribosomes in combination with impaired mitochondrial fission or fusion increases C. elegans lifespan by activating the transcription factor HLH-30, which promotes lysosomal biogenesis.

Rahmani, Shapour et al. (2021) MicroPubl Biol

Rahmani, Shapour, Tuck, Simon

[MicroPubl Biol, 2021]

C. elegans males that have come into close proximity of hermaphrodites initiate copulatory behavior comprising at least five different steps termed response, turning, location of vulva, spicule insertion and sperm transfer (Loer and Kenyon 1993, Liu and Sternberg 1995, Chute and Srinivasan 2014). Mutations specifically affecting different steps have been isolated and characterized (Barr and Sternberg 1999, Hajdu-Cronin et al. 2017, Liu et al. 2017). However, our understanding of the molecular mechanisms acting in the neurons controlling copulation is far from complete. During the response step, males that have sensed the presence of a hermaphrodite move backwards in such a way that the males tail fan glides along the surface of the hermaphrodite until the tail reaches the vulva (or head or tail) (Loer and Kenyon 1993, Liu and Sternberg 1995, Sherlekar and Lints 2014). Response behavior is regulated by ciliated neurons in the tail whose dendrites lie in sensory rays within the fan (Liu and Sternberg 1995). If a male reaches the end of the hermaphrodite without having found the vulva, it executes a turn during which the tail bends tightly ventrally so that contact is established between the ventral surface of the fan and the other side of the intended mate (Loer and Kenyon 1993, Liu and Sternberg 1995). The ability to execute turns efficiently is dependent upon serotonergic neurons in the posterior ventral nerve cord (the CP neurons) and on their ability to produce serotonin (Loer and Kenyon 1993, Carnell et al. 2005). Serotonin stimulates the diagonal muscles in the tail to induce curling ventrally by stimulating a serotonin receptor, SER-1 (Loer and Kenyon 1993, Carnell et al. 2005). However, how serotonin affects diagonal muscles and ventral turning is not fully understood.

Kirkwood TB (2013) Cell Metab "Untangling functional declines in the locomotion of aging worms."

Kirkwood TB

[Cell Metab, 2013]

All physiological functions decline with age, but which changes are primary and which are secondary is not always clear. Liu et al. (2013), examining functional changes in the muscles and motor neurons of C. elegans, suggest that when it comes to locomotion, it is the nervous system that shows earlier age-related deterioration.

Morrison, Kayleigh N. et al. (2021) MicroPubl Biol

Shakes, Diane C., Ragle, James Matthew, Uyehara, Christopher M., Ward, Jordan D., Morrison, Kayleigh N.

[MicroPubl Biol, 2021]

During the process of cell differentiation, specific cytoskeletal proteins can sequentially assemble into a wide variety of diverse molecular superstructures. Nematode spermatogenesis provides a powerful system for studying these transitions since sperm-specific transcription ceases prior to the meiotic divisions and translation ceases shortly thereafter (Chu and Shakes, 2013). Therefore, structural transitions that follow the meiotic divisions must be carried out by the remodeling of already synthesized proteins. The Major Sperm Protein (MSP) is a nematode-specific cytoskeletal element whose polymerization dynamics drive the pseudopod-based motility of the activated sperm (Roberts, 2005). In C. elegans, MSP additionally functions as the extracellular signaling molecule for triggering both ovulation and oocyte maturation (Miller et al., 2003). MSP is highly abundant in sperm, where it reaches 10-15% of total and 40% of soluble cellular protein (Roberts 2005). Within developing spermatocytes, MSP is packaged into fibrous bodymembranous organelle (FB-MO) complexes (Fig. 1A, Roberts et al., 1986). By assembling into paracrystalline FBs, MSP is both sequestered away from the critical meiotic processes of chromosome segregation and cytokinesis while also being packaged for efficient segregation into spermatids during the post-meiotic partitioning process (Chu and Shakes 2013, Nishimura and LHernault, 2010, Price et al., 2021). Following the meiotic divisions and sperm individualization, FBs disassemble, and MSP disperses as dimers throughout the spermatid cytoplasm (Fig. 1A). When sperm activate to form motile spermatozoa, MSP polymerization within the pseudopod drives the motility of the crawling sperm (Chu and Shakes, 2013). Thus, MSP exists in at least three distinct molecular states: 1) in highly organized paracrystalline FBs within developing spermatocytes 2) as unpolymerized dimers within spermatids, and 3) in dynamically polymerizing filaments and fibers within crawling spermatozoa.

Nicholas, Hannah R. et al. (2011) International Worm Meeting "Defining target genes of the transcriptional repressor protein CTBP-1."

Crossley, Merlin, Setiyaputra, Surya, Kant, Sashi, Nicholas, Hannah R., Lun, Aaron, Liu, Chu-Kong, Tan, Melinda S-Y, Mackay, Joel

[International Worm Meeting, 2011]

Mammalian members of the C-terminal binding protein family of transcriptional repressors are recruited to promoters through interactions with DNA-bound transcription factors that contain amino acid motifs of the form PXDLS. Although similarly able to interact with PXDLS-containing transcription factors, we have found that the sole C. elegans member of this protein family, CTBP-1, also contains intrinsic DNA binding capacity in the form of a THAP domain. We have identified additional THAP domain-containing CtBPs in the nematode, echinoderm and cephalochordate lineages. The distribution of these lineages within the animal kingdom suggests that the ancestral form of the animal CtBPs may have contained a THAP domain that was subsequently lost in the vertebrate lineage. Since determining the structure of the THAP domain of CTBP-1 by nuclear magnetic resonance spectroscopy, we have used a variety of biophysical approaches to define the DNA contact surface of this domain and to assess the affinity of binding to an 11 bp consensus binding site derived from site selection experiments. Using the CisOrtho program1 we have identified promoters that contain putative CTBP-1-THAP binding sites, representing candidate CTBP-1 target genes. With reference to both our own and published2 microarray datasets comparing transcripts from wild type animals with those from ctbp-1 mutants, and to expression pattern data, we have defined a sub-set of these as likely in vivo targets of CTBP-1-mediated repression. Given the reported role of CTBP-1 in the regulation of lifespan and stress resistance2, and other investigations implicating CTBP-1 in aspects of neuronal development (D. Yucel, unpublished), our identification of CTBP-1 target genes will make an important contribution to understanding the function of this transcriptional regulator in a range of contexts. 1.Bigelow HR, Wenick AS, Wong A, Hobert O. 2004. BMC Bioinformatics 5: 27 2.Chen S, Whetstine JR, Ghosh S, Hanover JA, Gali RR, et al. 2009. Proc Natl Acad Sci U S A 106: 1496-501.

Gary Schindelman et al. (2002) West Coast Worm Meeting "Characterization of the sperm transfer step of male mating behavior of Caenorhabditis elegans ."

Allyson J Whittaker, Gary Schindelman, Paul W Sternberg, Shahla Gharib

[West Coast Worm Meeting, 2002]

C. elegans male mating behavior involves the proper execution of a series of sub-behaviors culminating in the transfer of sperm to the hermaphrodite (Liu, KS and Sternberg, PW. 1995. Neuron 14:79-89). These sub-behaviors are: Response to hermaphrodite, backing, turning, vulval location, spicule insertion and sperm transfer. We are analyzing the genetic control of this stereotyped behavior as it may provide insight into sensory perception and nervous system function.

David S Peal et al. (2001) International C. elegans Meeting "Chemical and Genetic Inhibition of Sulfation in C. elegans"

David S Peal, Laura L Kiessling

[International C. elegans Meeting, 2001]

In order to examine the process of sulfation in C. elegans, sulfation was inhibited chemically using sodium chlorate, and genetically using the process of RNA-mediated interference (RNAi). Sodium chlorate inhibition during early larval stages resulted in a dose-dependant developmental delay. BLAST searches of characterized sulfotransferases against the worm genome resulted in the identification of 4 putative sulfotransferases: C34F6.4 and F08B4.6 (previously identified: [1] and [2]), F40H3.5, and Y34B4A.e. RNAi of the putative N-deacetylase/N-sulfotransferase F08B4.6 resulted in "stacking" of eggs in the gonad, along with eggs laid at the 2- and 4-celled stage. RNAi of the putative hexuronic 2-O sulfotransferase C34F6.4 resulted in a shortened, bulbous gonad. These initial results indicate that sulfation may be important during development of C. elegans. [1] Shworak, NW, Liu, J, Fritze, LMS, Schwartz, JJ, Zhang, L, Logeart, D, Rosenberg, RD. JBC 272: 28008-19 (1997). [2] Kobayashi, M, Sugumaran, G, Liu, J, Shworak, NW, Silbert, JE, Rosenberg, RD. JBC 274: 10474-80 (1999).

(2024) Development "The people behind the papers - Alyshia Scholl, Yihong Liu and Geraldine Seydoux."

[Development, 2024]

Germ granules have been hypothesized to deliver mRNAs of germ cell fate determinants to primordial germ cells. Now, a new study in Development finds that many mRNAs enriched in germ granules are not involved in germline development in Caenorhabditis elegans. To find out more about the story behind the paper, we caught up with first author Alyshia Scholl, second author Yihong Liu and corresponding author Geraldine Seydoux, Professor at Johns Hopkins University School of Medicine.

Skora S et al. (2013) EMBO J "Life(span) in balance: oxygen fuels a sophisticated neural network for lifespan homeostasis in C. elegans."

Zimmer M, Skora S

[EMBO J, 2013]

A key finding of modern ageing research is that our limitation in lifespan is more than the result of accumulated organismal decay. Lifespan is regulated by genetically defined chemosensory and endocrine pathways, which integrate signals that reflect the internal and external status of the animal. New findings by Liu and Cai unravel a role for the environmental gases oxygen and carbon dioxide in the regulation of lifespan homeostasis and thus a novel function of oxygen-chemosensory neurons in C. elegans.