Decreased Hsp90 activity protects against TDP-43 neurotoxicity in a C. elegans model of amyotrophic lateral sclerosis.

Neuronal inclusions of hyperphosphorylated TDP-43 are hallmarks of disease for most patients with amyotrophic lateral sclerosis (ALS). Mutations in TARDBP, the gene coding for TDP-43, can cause some cases of familial inherited ALS (fALS), indicating dysfunction of TDP-43 drives disease. Aggregated, phosphorylated TDP-43 may contribute to disease phenotypes; alternatively, TDP-43 aggregation may be a protective cellular response sequestering toxic protein away from the rest of the cell.

Anything you can do, glycans do better: deglycosylation and noncanonical ubiquitination vie to rule the proteasome.

The Nrf1/Nfe2L1 transcription factor is a master regulator of proteasome biogenesis. New work by Yoshida and colleagues reveals a surprising mechanism by which ubiquitination of N-glycosylated Nrf1 controls its function.

Mutations in nucleotide metabolism genes bypass proteasome defects in png-1/NGLY1-deficient Caenorhabditis elegans.

The conserved SKN-1A/Nrf1 transcription factor regulates the expression of proteasome subunit genes and is essential for maintenance of adequate proteasome function in animal development, aging, and stress responses. Unusual among transcription factors, SKN-1A/Nrf1 is a glycoprotein synthesized in the endoplasmic reticulum (ER). N-glycosylated SKN-1A/Nrf1 exits the ER and is deglycosylated in the cytosol by the PNG-1/NGLY1 peptide:N-glycanase.

Streamlined single shot safe harbor transgene integration in using rescue.

Transgenic animals are an invaluable tool in model organism genetics. The ease of modifying the genome through high-copy integration of transgenes facilitates the investigation of diverse and fundamental biological processes. However, generation of new multicopy integrated transgenes is limited by the time and labor cost.

An antisteatosis response regulated by oleic acid through lipid droplet-mediated ERAD enhancement.

Although excessive lipid accumulation is a hallmark of obesity-related pathologies, some lipids are beneficial. Oleic acid (OA), the most abundant monounsaturated fatty acid (FA), promotes health and longevity. Here, we show that OA benefits by activating the endoplasmic reticulum (ER)-resident transcription factor SKN-1A (Nrf1/NFE2L1) in a lipid homeostasis response.

Regulation and Functions of the ER-Associated Nrf1 Transcription Factor.

Nrf1 is a member of the nuclear erythroid 2-like family of transcription factors that regulate stress-responsive gene expression in animals. Newly synthesized Nrf1 is targeted to the endoplasmic reticulum (ER) where it is -glycosylated. -glycosylated Nrf1 is trafficked to the cytosol by the ER-associated degradation (ERAD) machinery and is subject to rapid proteasomal degradation.

NGLY1: insights from Caenorhabditis elegans.

Peptide:N-glycanase is an evolutionarily conserved deglycosylating enzyme that catalyses the removal of N-linked glycans from cytosolic glycoproteins. Recessive mutations that inactivate this enzyme cause NGLY1 deficiency, a multisystemic disorder with symptoms including developmental delay and defects in cognition and motor control. Developing treatments for NGLY1 deficiency will require an understanding of how failure to deglycosylate NGLY1 substrates perturbs cellular and organismal function.

Protein Sequence Editing of SKN-1A/Nrf1 by Peptide:N-Glycanase Controls Proteasome Gene Expression.

The proteasome mediates selective protein degradation and is dynamically regulated in response to proteotoxic challenges. SKN-1A/Nrf1, an endoplasmic reticulum (ER)-associated transcription factor that undergoes N-linked glycosylation, serves as a sensor of proteasome dysfunction and triggers compensatory upregulation of proteasome subunit genes. Here, we show that the PNG-1/NGLY1 peptide:N-glycanase edits the sequence of SKN-1A protein by converting particular N-glycosylated asparagine residues to aspartic acid.

Endoplasmic reticulum-associated SKN-1A/Nrf1 mediates a cytoplasmic unfolded protein response and promotes longevity.

Unfolded protein responses (UPRs) safeguard cellular function during proteotoxic stress and aging. In a previous paper (Lehrbach and Ruvkun, 2016) we showed that the ER-associated SKN-1A/Nrf1 transcription factor activates proteasome subunit expression in response to proteasome dysfunction, but it was not established whether SKN-1A/Nrf1 adjusts proteasome capacity in response to other proteotoxic insults. Here, we reveal that misfolded endogenous proteins and the human amyloid beta peptide trigger activation of proteasome subunit expression by SKN-1A/Nrf1.

Endoplasmic Reticulum Homeostasis Is Modulated by the Forkhead Transcription Factor FKH-9 During Infection of .

Animals have evolved critical mechanisms to maintain cellular and organismal proteostasis during development, disease, and exposure to environmental stressors. The Unfolded Protein Response (UPR) is a conserved pathway that senses and responds to the accumulation of misfolded proteins in the endoplasmic reticulum (ER) lumen. We have previously demonstrated that the IRE-1-XBP-1 branch of the UPR is required to maintain ER homeostasis during larval development in the presence of pathogenic In this study, we identify loss-of-function mutations in four conserved transcriptional regulators that suppress the larval lethality of mutant animals caused by immune activation in response to infection by pathogenic bacteria: FKH-9, a forkhead family transcription factor; ARID-1, an ARID/Bright domain-containing transcription factor; HCF-1, a transcriptional regulator that associates with histone modifying enzymes; and SIN-3, a subunit of a histone deacetylase complex.

Next-Generation Sequencing for Identification of EMS-Induced Mutations in Caenorhabditis elegans.

Forward genetic analysis using chemical mutagenesis in model organisms is a powerful tool for investigation of molecular mechanisms in biological systems. In the nematode, Caenorhabditis elegans, mutagenesis screens using ethyl methanesulfonate (EMS) have led to important insights into genetic control of animal development and physiology. A major bottleneck to this approach is identification of the causative mutation underlying a phenotype of interest.

Proteasome dysfunction triggers activation of SKN-1A/Nrf1 by the aspartic protease DDI-1.

Proteasomes are essential for protein homeostasis in eukaryotes. To preserve cellular function, transcription of proteasome subunit genes is induced in response to proteasome dysfunction caused by pathogen attacks or proteasome inhibitor drugs. In Caenorhabditis elegans, this response requires SKN-1, a transcription factor related to mammalian Nrf1/2.

Tertiary siRNAs mediate paramutation in C. elegans.

In the nematode Caenorhabditis elegans, different small RNA-dependent gene silencing mechanisms act in the germline to initiate transgenerational gene silencing. Piwi-interacting RNAs (piRNAs) can initiate transposon and gene silencing by acting upstream of endogenous short interfering RNAs (siRNAs), which engage a nuclear RNA interference (RNAi) pathway to trigger transcriptional gene silencing. Once gene silencing has been established, it can be stably maintained over multiple generations without the requirement of the initial trigger and is also referred to as RNAe or paramutation.

RNA-binding protein GLD-1/quaking genetically interacts with the mir-35 and the let-7 miRNA pathways in Caenorhabditis elegans.

Messenger RNA translation is regulated by RNA-binding proteins and small non-coding RNAs called microRNAs. Even though we know the majority of RNA-binding proteins and microRNAs that regulate messenger RNA expression, evidence of interactions between the two remain elusive. The role of the RNA-binding protein GLD-1 as a translational repressor is well studied during Caenorhabditis elegans germline development and maintenance.

A deletion polymorphism in the Caenorhabditis elegans RIG-I homolog disables viral RNA dicing and antiviral immunity.

RNA interference defends against viral infection in plant and animal cells. The nematode Caenorhabditis elegans and its natural pathogen, the positive-strand RNA virus Orsay, have recently emerged as a new animal model of host-virus interaction. Using a genome-wide association study in C.

A study of Caenorhabditis elegans DAF-2 mutants by metabolomics and differential correlation networks.

daf-2 is one of the most studied mutants in C. elegans: it contains a deletion in the gene orthologue of the insulin/insulin-like growth factor (IGF) receptor. Using high resolution (1)H NMR spectroscopy, metabolomics has helped to dissect the metabolic consequences of altered daf-2 signalling.

Post-developmental microRNA expression is required for normal physiology, and regulates aging in parallel to insulin/IGF-1 signaling in C. elegans.

Regulation of gene expression by microRNAs (miRNAs) is essential for normal development, but the roles of miRNAs in the physiology of adult animals are poorly understood. We have isolated a conditional allele of DGCR8/pash-1, which allows reversible and rapid inactivation of miRNA synthesis in vivo in Caenorhabditis elegans. This is a powerful new tool that allows dissection of post-developmental miRNA functions.

piRNAs can trigger a multigenerational epigenetic memory in the germline of C. elegans.

Transgenerational effects have wide-ranging implications for human health, biological adaptation, and evolution; however, their mechanisms and biology remain poorly understood. Here, we demonstrate that a germline nuclear small RNA/chromatin pathway can maintain stable inheritance for many generations when triggered by a piRNA-dependent foreign RNA response in C. elegans.

Function, targets, and evolution of Caenorhabditis elegans piRNAs.

Piwi-interacting RNAs (piRNAs) are small RNAs required to maintain germline integrity and fertility, but their mechanism of action is poorly understood. Here we demonstrate that Caenorhabditis elegans piRNAs silence transcripts in trans through imperfectly complementary sites. Target silencing is independent of Piwi endonuclease activity or "slicing.

A LIN28-dependent structural change in pre-let-7g directly inhibits dicer processing.

Several recent studies have provided evidence that LIN28, a cytoplasmic RNA-binding protein, inhibits the biogenesis of members of the let-7 microRNA family at the Dicer step in both mammals and Caenorhabditis elegans. However, the precise mechanism of inhibition is still poorly understood. Here we report on an in vitro study, which combined RNase footprinting, gel shift binding assays, and processing assays, to investigate the molecular basis and function of the interaction between the native let-7g precursor (pre-let-7g) and LIN28.

Regulation of pre-miRNA Processing.

microRNAs are endogenously expressed ∼21 nucleotide noncoding RNAs. microRNA-mediated regulation of the translation of specific mRNA is implicated in a range of developmental processes and pathologies. As such, miRNA expression is tightly controlled in normal development by both transcriptional and post-transcriptional mechanisms.

A quantitative targeted proteomics approach to validate predicted microRNA targets in C. elegans.

Efficient experimental strategies are needed to validate computationally predicted microRNA (miRNA) target genes. Here we present a large-scale targeted proteomics approach to validate predicted miRNA targets in Caenorhabditis elegans. Using selected reaction monitoring (SRM), we quantified 161 proteins of interest in extracts from wild-type and let-7 mutant worms.

The conserved miR-51 microRNA family is redundantly required for embryonic development and pharynx attachment in Caenorhabditis elegans.

microRNAs (miRNAs) are approximately 22-nucleotide small RNAs that act as endogenous regulators of gene expression by base-pairing with target mRNAs. Here we analyze the function of the six members of the Caenorhabditis elegans miR-51 family of miRNAs (miR-51, miR-52, miR-53, miR-54, miR-55, miR-56). miR-51 family miRNAs are broadly expressed from mid-embryogenesis onward.

Regulation of pre-miRNA processing.

microRNAs are endogenously expressed 21 nucleotide noncoding RNAs. microRNA-mediated regulation of the translation of specific mRNA is implicated in a range of developmental processes and pathologies. As such, miRNA expression is tightly controlled in normal development by both transcriptional and post-transcriptional mechanisms.