Explore the vast range of titles available.

Methods that use homologous recombination to engineer the genome of C. elegans commonly use strains carrying specific insertions of the heterologous transposon Mos1. A large collection of known Mos1 insertion alleles would therefore be of general interest to the C. elegans research community. We describe here the optimization of a semi-automated methodology for the construction of a substantial collection of Mos1 insertion mutant strains. At peak production, more than 5,000 strains were generated per month. These strains were then subject to molecular analysis, and more than 13,300 Mos1 insertions characterized. In addition to targeting directly more than 4,700 genes, these alleles represent the potential starting point for the engineered deletion of essentially all C. elegans genes and the modification of more than 40% of them. This collection of mutants, generated under the auspices of the European NEMAGENETAG consortium, is publicly available and represents an important research resource.

Determining the sub-cellular localization of a protein within a cell is often an essential step towards understanding its function. In Caenorhabditis elegans, the relatively large size of the body wall muscle cells and the exquisite organization of their sarcomeres offer an opportunity to identify the precise position of proteins within cell substructures. Our goal in this study is to generate a comprehensive \"localizome\" for C. elegans body wall muscle by GFP-tagging proteins expressed in muscle and determining their location within the cell. For this project, we focused on proteins that we know are expressed in muscle and are orthologs or at least homologs of human proteins. To date we have analyzed the expression of about 227 GFP-tagged proteins that show localized expression in the body wall muscle of this nematode (e.g. dense bodies, M-lines, myofilaments, mitochondria, cell membrane, nucleus or nucleolus). For most proteins analyzed in this study no prior data on sub-cellular localization was available. In addition to discrete sub-cellular localization we observe overlapping patterns of localization including the presence of a protein in the dense body and the nucleus, or the dense body and the M-lines. In total we discern more than 14 sub-cellular localization patterns within nematode body wall muscle. The localization of this large set of proteins within a muscle cell will serve as an invaluable resource in our investigation of muscle sarcomere assembly and function.

The expression of DCC (deleted in colorectal cancer) is often markedly reduced in colorectal and other cancers. However, the rarity of point mutations identified in DCC coding sequences and the lack of a tumor predisposition phenotype in DCC hemizygous mice have raised questions about its role as a tumor suppressor. DCC also mediates axon guidance and functions as a dependence receptor; such receptors create cellular states of dependence on their respective ligands by inducing apoptosis when unoccupied by ligand. We now show that DCC drives cell death independently of both the mitochondria-dependent pathway and the death receptor/caspase-8 pathway. Moreover, we demonstrate that DCC interacts with both caspase-3 and caspase-9 and drives the activation of caspase-3 through caspase-9 without a requirement for cytochrome c or Apaf-1. Hence, DCC defines an additional pathway for the apoptosome-independent caspase activation.

The RET ( re arranged during t ransfection) proto‐oncogene encodes a tyrosine kinase receptor involved in both multiple endocrine neoplasia type 2 (MEN 2), an inherited cancer syndrome, and Hirschsprung disease (HSCR), a developmental defect of enteric neurons. We report here that the expression of RET receptor induces apoptosis. This pro‐apoptotic effect of RET is inhibited in the presence of its ligand glial cell line‐derived neurotrophic factor (GDNF). Furthermore, we present evidence that RET induces apoptosis via its own cleavage by caspases, a phenomenon allowing the liberation/exposure of a pro‐apoptotic domain of RET. In addition, we report that Hirschsprung‐associated RET mutations impair GDNF control of RET pro‐apoptotic activity. These results indicate that HSCR may result from apoptosis of RET‐expressing enteric neuroblasts.

Serotonin (5-HT) regulates a wide range of behaviors in Caenorhabditis elegans, including egg laying, male mating, locomotion and pharyngeal pumping. So far, four serotonin receptors have been described in the nematode C. elegans, three of which are G protein-coupled receptors (GPCR), (SER-1, SER-4 and SER-7), and one is an ion channel (MOD-1). By searching the C. elegans genome for additional 5-HT GPCR genes, we identified five further genes which encode putative 5-HT receptors, based on sequence similarities to 5-HT receptors from other species. Using loss-of-function mutants and RNAi, we performed a systematic study of the role of the eight GPCR genes in serotonin-modulated behaviors of C. elegans (F59C12.2, Y22D7AR.13, K02F2.6, C09B7.1, M03F4.3, F16D3.7, T02E9.3, C24A8.1). We also examined their expression patterns. Finally, we tested whether the most likely candidate receptors were able to modulate adenylate cyclase activity in transfected cells in a 5-HT-dependent manner. This paper is the first comprehensive study of G protein-coupled serotonin receptors of C. elegans. It provides a direct comparison of the expression patterns and functional roles for 5-HT receptors in C. elegans.

Axon termination is a critical step in neural circuit formation, but the contribution of activity from postsynaptic targets to this process remains unclear. Using SAB neurons as a model system, we showed that inhibition of muscle activity during a critical period of postembryonic development led to axonal overgrowth and ectopic synapse formation. This effect is mediated by a local retrograde signal and requires neuronal voltage-gated calcium channels (VGCCs) acting cell-autonomously to constrain axon growth. Manipulating SAB neuron excitability demonstrated that increased intrinsic neuronal activity drives overgrowth, while reducing activity suppresses it, establishing a functional link between muscle-derived cues and presynaptic excitability. Transcriptomic analysis and genetic studies further implicate the neuropeptides FLP-18 and NLP-12 as essential modulators of this activity-dependent process. Our findings reveal a temporally and spatially restricted retrograde signaling mechanism in motor neurons, where target activity, neuronal calcium dynamics and neuropeptide signaling cooperate to ensure proper axon termination. These results highlight conserved principles of activity-dependent regulation at neuromuscular junctions and provide a framework for understanding how motor circuits integrate target feedback to sculpt precise connectivity.

The precise localization of postsynaptic receptors opposite neurotransmitter release sites is essential for synaptic function. This alignment relies on adhesion molecules, intracellular scaffolds, and a growing class of extracellular scaffolding proteins. However, how these secreted proteins are retained at synapses remains unclear. We addressed this question using C. elegans neuromuscular junctions, where Punctin, a conserved extracellular synaptic organizer, positions postsynaptic receptors. We identified CLE-1, the ortholog of collagens XV/XVIII, as a key stabilizer of Punctin. Punctin and CLE-1B, the main isoform present at neuromuscular junctions, form a complex and rely on each other for synaptic localization. Punctin undergoes cleavage, and in the absence of CLE-1, specific fragments are lost, resulting in the mislocalization of cholinergic receptors to GABAergic synapses. Additionally, CLE-1 regulates receptor levels independently of Punctin. These findings highlight a crucial extracellular complex that maintains synapse identity.

The expression of DCC (deleted in colorectal cancer) is often markedly reduced in colorectal and other cancers. However, the rarity of point mutations identified in DCC coding sequences and the lack of a tumor predisposition phenotype in DCC hemizygous mice have raised questions about its role as a tumor suppressor. DCC also mediates axon guidance and functions as a dependence receptor; such receptors create cellular states of dependence on their respective ligands by inducing apoptosis when unoccupied by ligand. We now show that DCC drives cell death independently of both the mitochondria-dependent pathway and the death receptor/caspase-8 pathway. Moreover, we demonstrate that DCC interacts with both caspase-3 and caspase-9 and drives the activation of caspase-3 through caspase-9 without a requirement for cytochrome c or Apaf-1. Hence, DCC defines an additional pathway for the apoptosome-independent caspase activation.

Background Although treatment‐resistant and nontreatment‐resistant depressed patients show structural brain anomalies relative to healthy controls, the difference in regional volumetry between these two groups remains undocumented. Methods A whole‐brain voxel‐based morphometry (VBM) analysis of regional volumes was performed in 125 participants’ magnetic resonance images obtained on a 1.5 Tesla scanner; 41 had treatment‐resistant depression (TRD), 40 nontreatment‐resistant depression (non‐TRD), and 44 were healthy controls. The groups were comparable for age and gender. Bipolar/unipolar features as well as pharmacological treatment classes were taken into account as covariates. Results TRD patients had higher gray matter (GM) volume in the left and right amygdala than non‐TRD patients. No difference was found between the TRD bipolar and the TRD unipolar patients, or between the non‐TRD bipolar and non‐TRD unipolar patients. An exploratory analysis showed that lithium‐treated patients in both groups had higher GM volume in the superior and middle frontal gyri in both hemispheres. Conclusions Higher GM volume in amygdala detected in TRD patients might be seen in perspective with vulnerability to chronicity, revealed by medication resistance.

Abstract Introduction Predictive markers of LV5FU2 maintenance benefit after first-line induction with FOLFIRINOX in patients with metastatic pancreatic cancer are necessary to select patients who will not be harmed by this strategy. Patients and Methods We focused on patients who received 12 cycles of FOLFIRINOX (arm A, N = 88) or 8 cycles of FOLFIRINOX followed by LV5FU2 maintenance in controlled patients (arm B, N = 91) from the PRODIGE-35 trial. Prognostic factors and predictors of efficiency were identified by using Cox regression. Median progression-free survival (PFS), overall survival (OS), and time to deterioration of quality of life (TTD-QoL) were evaluated. Results Poor independent prognostic factors were primary tumor in place, age <65 years and the presence of liver metastases for PFS, a baseline neutrophil/lymphocyte ratio (NLR) ≥5 and CA19.9 ≥500 UI/L for OS, independent of the treatment arm. Patients with one metastatic site had a longer PFS in arm A, whereas patients with ≥2 metastatic sites had a longer PFS in arm B. We also identified predictors of OS and TTD-QoL in arm B but these differences were not statistically significant. Conclusion Except for patients with one metastatic site who benefited more from 12 cycles of FOLFIRINOX, a maintenance strategy with LV5FU2 should be widely offered to mPC patients whose survival and QoL are preserved after 4 months of FOLFIRINOX. (ClinicalTrials.gov: NCT02352337). This retrospective analysis of the PRODIGE-35 trial showed that LV5FU2 maintenance after 8 cycles of FOLFIRINOX is feasible in patients treated first line for metastatic pancreatic cancer.