Sowa, J. et al. (2019) International Worm Meeting "C. elegans RIG-I homolog drh-1 mediates a transcriptional response to Orsay virus infection."

Wang, D., Somasundaram, L., Troemel, E., Sowa, J., Jiang, H.

[International Worm Meeting, 2019]

The field of C. elegans host/pathogen interactions has historically focused on infections by extracellular pathogens. However, more recently there have been several intracellular pathogens found infecting C. elegans in the wild. These include the Orsay virus and several species of microsporidia, a phylum of eukaryotic intracellular pathogens. Previously, our lab identified a common set of genes that are highly upregulated by both microsporidia and the Orsay virus that we have termed the Intracellular Pathogen Response (IPR) (Bakowski et al, 2014; Reddy et al., 2017). These genes are distinct from genes induced by extracellular pathogens and many other classical stressors. Importantly, mutants with constitutive expression of IPR genes have increased resistance to microsporidia and Orsay virus, indicating the IPR provides defense (Reddy et al., 2019). Previous work demonstrated that the anti-viral RNAi response against Orsay virus in C. elegans involves the RIG-I homolog drh-1, and we now report that drh-1 is also required for IPR induction upon Orsay virus infection. Interestingly, drh-1 is not required for IPR induction by microsporidia or other known IPR triggers. In fact, drh-1 mutants had stronger IPR induction in response to some other triggers. We further found that IPR activation in response to virus does not require known RNAi factors, suggesting that the signaling role of drh-1 in IPR activation is distinct from its previously known role in antiviral RNAi. Previous analysis of transgenic worms expressing the Orsay virus RNA1, which encodes an RNA-dependent RNA polymerase, showed that RNA1 alone was sufficient to activate an IPR reporter, and that this activation required the RDRP activity of RNA1 (Jiang et al, 2017). Here we show this activation is dependent on drh-1, and demonstrate that several IPR genes are induced by this trigger. Together these results indicate that drh-1 triggers the IPR in response to viral dsRNA replication intermediates, and highlight a similarity between worms and mammals, with both detecting viral dsRNAs via a RIG-I -like receptor to activate a protective transcriptional response.

Sowa JN et al. (2019) J Virol "The C. elegans RIG-I homolog DRH-1 mediates the Intracellular Pathogen Response upon viral infection."

Troemel ER, Tecle E, Sowa JN, Wang D, Somasundaram L, Xu G, Jiang H

[J Virol, 2019]

Mammalian RIG-I-like receptors detect viral dsRNA and 5' triphosphorylated RNA to activate transcription of interferon genes and promote antiviral defense. The <i>C. elegans</i> RIG-I-like receptor DRH-1 promotes defense through antiviral RNA interference, but less is known about its role in regulating transcription. Here we describe a role for DRH-1 in directing a transcriptional response in <i>C. elegans</i> called the Intracellular Pathogen Response (IPR), which is associated with increased pathogen resistance. The IPR includes a set of genes induced by diverse stimuli including intracellular infection and proteotoxic stress. Previous work suggested that the proteotoxic stress caused by intracellular infections might be the common trigger of the IPR, but here we demonstrate that different stimuli act through distinct pathways. Specifically, we demonstrate that DRH-1/RIG-I is required for inducing the IPR in response to Orsay virus infection, but not in response to other triggers like microsporidian infection or proteotoxic stress. Furthermore, DRH-1 appears to be acting independently of its known role in RNAi. Interestingly, expression of the replication competent Orsay virus RNA1 segment alone is sufficient to induce most of the IPR genes in a manner dependent on RNA-dependent RNA polymerase activity and on DRH-1. Altogether, these results suggest that DRH-1 is a pattern-recognition receptor that detects viral replication products to activate the IPR stress/immune program in <i>C. elegans</i><b>Importance</b><i>C. elegans</i> lacks homologs of most mammalian pattern recognition receptors, and how nematodes detect pathogens is poorly understood. We show that the <i>C. elegans</i> RIG-I homolog DRH-1 mediates induction of the Intracellular Pathogen Response (IPR), a novel transcriptional defense program, in response to infection by the natural <i>C. elegans</i> viral pathogen Orsay virus. DRH-1 appears to act as a pattern-recognition receptor to induce the IPR transcriptional defense program by sensing the products of viral RNA-dependent RNA polymerase activity. Interestingly, this signaling role of DRH-1 is separable from its previously known role in antiviral RNAi. In addition, we show that there are multiple host pathways for inducing the IPR, shedding light on the regulation of this novel transcriptional immune response.

McGhee JD (1987) Biochemistry "Purification and characterization of a carboxylesterase from the intestine of the nematode Caenorhabditis elegans."

McGhee JD

[Biochemistry, 1987]

The major intestinal esterase from the nematode Caenorhabditis elegans has been purified to essential homogeneity. Starting from whole worms, the overall purification is 9000-fold with a 10% recovery of activity. The esterase is a single polypeptide chain of Mr 60,000 and is stoichiometrically inhibited by organophosphates. Substrate preferences and inhibition patterns classify the enzyme as a carboxylesterase (EC 3.1.1.1), but the physiological function is unknown. The sequence of 13 amino acid residues at the esterase N- terminus has been determined. This partial sequence shows a surprisingly high degree of similarity to the N-terminal sequence of two carboxylesterases recently isolated from Drosophila mojavensis [Pen, J., van Beeumen, J., & Beintema, J. J. (1986) Biochem. J. 238, 691-699].

Murakami S et al. (1999) Curr Biol "Life extension and stress resistance in Caenorhabditis elegans modulated by the tkr-1 gene."

Johnson TE, Murakami S

[Curr Biol, 1999]

In this Brief Communication, which appeared in the 14 September 1998 issue of Current Biology, the UV dose was reported erroneously. The dose reported was 20 J/m2 but the actual dose used was 0.4 J/cm2. Also, the gene formally referred to as tkr-1 has since been renamed old-1 (overexpression longevity determination).

Ramos CG et al. (2014) J Bacteriol "Retraction for Ramos et al., MtvR is a global small noncoding regulatory RNA in Burkholderia cenocepacia."

Feliciano JR, da Costa PJ, Ramos CG, Grilo AM, Leitao JH

[J Bacteriol, 2014]

Volume 195, no. 16, p. 35143523, 2013. A number of problems related to images published in this paper have been brought to our attention. Figure 1D contains duplicated images in lanes S and LE, and Fig. 4D and 6B contain images previously published in articles in this journal and in Microbiology and Microbial Pathogenesis, i.e., the following: C. G. Ramos, S. A. Sousa, A. M. Grilo, J. R. Feliciano, and J. H. Leitao, J. Bacteriol. 193:15151526, 2011. doi:10.1128/JB.01374-11. S. A. Sousa, C. G. Ramos, L. M. Moreira, and J. H. Leitao, Microbiology 156:896908, 2010. doi:10.1099/mic.0.035139-0. C. G. Ramos, S. A. Sousa, A. M. Grilo, L. Eberl, and J. H. Leitao, Microb. Pathog. 48:168177, 2010. doi: 10.1016/j.micpath.2010.02.006. Therefore, we retract the paper. We deeply regret this situation and apologize for any inconvenience to the editors and readers of Journal of Bacteriology, Microbial Pathogenesis, and Microbiology.

Nillegoda NB et al. (2015) Nature "Crucial HSP70 co-chaperone complex unlocks metazoan protein disaggregation."

Berynskyy M, Morimoto RI, Bukau B, Stengel F, Kirstein J, Szlachcic A, Arnsburg K, Stank A, Scior A, Nillegoda NB, Gao X, Guilbride DL, Aebersold R, Wade RC, Mayer MP

[Nature, 2015]

Protein aggregates are the hallmark of stressed and ageing cells, and characterize several pathophysiological states. Healthy metazoan cells effectively eliminate intracellular protein aggregates, indicating that efficient disaggregation and/or degradation mechanisms exist. However, metazoans lack the key heat-shock protein disaggregase HSP100 of non-metazoan HSP70-dependent protein disaggregation systems, and the human HSP70 system alone, even with the crucial HSP110 nucleotide exchange factor, has poor disaggregation activity in vitro. This unresolved conundrum is central to protein quality control biology. Here we show that synergic cooperation between complexed J-protein co-chaperones of classes A and B unleashes highly efficient protein disaggregation activity in human and nematode HSP70 systems. Metazoan mixed-class J-protein complexes are transient, involve complementary charged regions conserved in the J-domains and carboxy-terminal domains of each J-protein class, and are flexible with respect to subunit composition. Complex formation allows J-proteins to initiate transient higher order chaperone structures involving HSP70 and interacting nucleotide exchange factors. A network of cooperative class A and B J-protein interactions therefore provides the metazoan HSP70 machinery with powerful, flexible, and finely regulatable disaggregase activity and a further level of regulation crucial for cellular protein quality control.

Miller DM et al. (1992) Worm Breeder's Gazette "unc-4 LacZ Expression in A-Type Motor Neurons"

Miller DM, Niemeyer CJ

[Worm Breeder's Gazette, 1992]

unc-4 LacZ expression in A-type motor neurons David M. Miller and Charles J. Niemeyer, Dept. of Cell Biology, Duke Univ. Medical Ctr, Durham, NC 27710

Sommer RJ et al. (1994) Worm Breeder's Gazette "Evolution of Vulva-Formation: Part II: Species With a Central Vulva"

Sommer RJ, Sternberg PW

[Worm Breeder's Gazette, 1994]

Evolution of vulva-formation: Part II: Species with a central vulva Ralf J. Sommer & Paul W. Sternberg, California Institute of Technology, Division of Biology 156-29, Pasadena, CA 91125

Jun-ichi Aikawa (2001) International C. elegans Meeting "Molecular characterization of heparan sulfate/heparin N-deacetylase/N-sulfotransferase in worms"

Jun-ichi Aikawa

[International C. elegans Meeting, 2001]

Heparan sulfate binds and activates a large variety of growth factors, enzymes and extracellular matrix proteins. These interactions largely depend on the specific arrangement of sulfated moieties and uronic acid epimers within the chains. These oligosaccharide sequences are generated in a step-wise manner, initiated by the formation of a linkage tetrasaccharide which is then extended by copolymerization of alternating a1,4GlcNAc and b1,4GlcA residues. As the chains polymerize, they undergo a series of sulfation and epimerization reactions. The first set of modifications involves the removal of acetyl units from subsets of GlcNAc residues, and the addition of sulfate groups to the resulting free amino groups. These reactions are catalyzed by a family of enzymes designated as GlcNAc N-deacetylase/N-sulfotransferases (NDST), since they simultaneously. Four members of the family have been identified in vertebrates, with single orthologs present in Drosophila and C. elegans. We have revealed tissue-specific expression pattern and unique enzymatic properties of these four isozymes1,2). In fly, loss of NDST (sulfateless) results in unsulfated chains and defective signaling by multiple growth factors and morphogens. I reconstituted cDNA for worm NDST from EST clones and 5' RACE products. Enzymatic activities will be discussed. 1) Aikawa, J. & Esko, J. D J. Biol. Chem. 274, 2690-2695 (1999) 2) Aikawa, J., Grobe, K., Tsujimoto, M. & Esko, J. D J. Biol. Chem. 276, 5876-5882 (2001)

Dreyfus DH et al. (1999) Mol Immunol "Comparative analysis of invertebrate Tc6 sequences that resemble the vertebrate V(D)J recombination signal sequences (RSS)."

Gelfand EW, Dreyfus DH

[Mol Immunol, 1999]

Invertebrate cells lack the p53 recombination checkpoint but contain mobile DNA sequences that transpose by a mechanism in part shared with excision of the V(D)J recombination signal sequences (RSS). In this work, inversion, deletion, and duplication of sequences associated with an invertebrate C. elegans Tc6 element is described. The structure of this C. elegans sequence and other dispersed Tc6 elements suggests that covalently closed 'hairpin' structures are not unique to excision of the V(D)J RSS by the RAG proteins, but rather can be generated by transposases at transposon termini leading to characteristic inversion and duplication events. Comparative analysis of recombination events at invertebrate sequences resembling the vertebrate V(D)J RSS may be useful in understanding V(D)J recombination-mediated recombination events in malignant vertebrate cells or genetic diseases such as ataxia telangectasia, in which the p53 recombination checkpoint is defective.