Structure of RDE-4 dsRBDs and mutational studies provide insights into dsRNA recognition in the Caenorhabditis elegans RNAi pathway

2014 ◽  
Vol 458 (1) ◽  
pp. 119-130 ◽  
Author(s):  
Sai Chaitanya Chiliveri ◽  
Mandar V. Deshmukh

RDE-4 initiates the RNAi pathway in Caenorhabditis elegans. Structural studies on RDE-4 dsRBDs illustrate the indispensible role of dsRBD2 and linker in dsRNA recognition and Dicer activity. The structure-based mutagenesis identifies two tandem lysine residues that drive the dsRNA recognition.

2018 ◽  
Vol 24 (26) ◽  
pp. 3072-3083 ◽  
Author(s):  
Sowndramalingam Sankaralingam ◽  
Angham Ibrahim ◽  
MD Mizanur Rahman ◽  
Ali H. Eid ◽  
Shankar Munusamy

Background: The incidence and prevalence of diabetes mellitus are increasing globally at alarming rates. Cardiovascular and renal complications are the major cause of morbidity and mortality in patients with diabetes. Methylglyoxal (MG) - a highly reactive dicarbonyl compound – is increased in patients with diabetes and has been implicated to play a detrimental role in the etiology of cardiovascular and renal complications. Derived from glucose, MG binds to arginine and lysine residues in proteins, and the resultant end products serve as surrogate markers of MG generation in vivo. Under normal conditions, MG is detoxified by the enzyme glyoxalase 1 (Glo1), using reduced glutathione as a co-factor. Elevated levels of MG is known to cause endothelial and vascular dysfunction, oxidative stress and atherosclerosis; all of which are risk factors for cardiovascular diseases. Moreover, MG has also been shown to cause pathologic structural alterations and impair kidney function. Conversely, MG scavengers (such as N-acetylcysteine, aminoguanidine or metformin) or Nrf2/Glo1 activators (such as trans-resveratrol / hesperetin) are shown to be useful in preventing MG-induced cardiovascular and renal complications in diabetes. However, clinical evidence supporting the MG lowering properties of these agents are limited and hence, need further investigation. Conclusion: Reducing MG levels directly using scavengers or indirectly via activation of Nrf2/Glo1 may serve as a novel and potent therapeutic strategy to counter the deleterious effects of MG in diabetic complications.


2019 ◽  
Vol 9 (11) ◽  
pp. 3825-3832 ◽  
Author(s):  
Dylan C. Wallis ◽  
Dieu An H. Nguyen ◽  
Celja J. Uebel ◽  
Carolyn M. Phillips

Genetics ◽  
2003 ◽  
Vol 163 (2) ◽  
pp. 571-580 ◽  
Author(s):  
William B Raich ◽  
Celine Moorman ◽  
Clay O Lacefield ◽  
Jonah Lehrer ◽  
Dusan Bartsch ◽  
...  

Abstract The pathology of trisomy 21/Down syndrome includes cognitive and memory deficits. Increased expression of the dual-specificity protein kinase DYRK1A kinase (DYRK1A) appears to play a significant role in the neuropathology of Down syndrome. To shed light on the cellular role of DYRK1A and related genes we identified three DYRK/minibrain-like genes in the genome sequence of Caenorhabditis elegans, termed mbk-1, mbk-2, and hpk-1. We found these genes to be widely expressed and to localize to distinct subcellular compartments. We isolated deletion alleles in all three genes and show that loss of mbk-1, the gene most closely related to DYRK1A, causes no obvious defects, while another gene, mbk-2, is essential for viability. The overexpression of DYRK1A in Down syndrome led us to examine the effects of overexpression of its C. elegans ortholog mbk-1. We found that animals containing additional copies of the mbk-1 gene display behavioral defects in chemotaxis toward volatile chemoattractants and that the extent of these defects correlates with mbk-1 gene dosage. Using tissue-specific and inducible promoters, we show that additional copies of mbk-1 can impair olfaction cell-autonomously in mature, fully differentiated neurons and that this impairment is reversible. Our results suggest that increased gene dosage of human DYRK1A in trisomy 21 may disrupt the function of fully differentiated neurons and that this disruption is reversible.


2007 ◽  
Vol 21 (8) ◽  
pp. 1801-1812 ◽  
Author(s):  
Martin Hasshoff ◽  
Claudia Höhnisch ◽  
Daniela Tonn ◽  
Barbara Hasert ◽  
Hinrich Schulenburg

RSC Advances ◽  
2015 ◽  
Vol 5 (95) ◽  
pp. 77706-77715 ◽  
Author(s):  
Supinder Kaur ◽  
Aamir Nazir

Studies employing transgenicC. elegansmodel show that trehalose, a protein stabilizer, alleviates manifestations associated with Parkinson's diseaseviaits inherent activity and through induction of autophagic machinery.


2018 ◽  
Vol 74 (1) ◽  
pp. 41-51
Author(s):  
Kazuhiro Yamada ◽  
Markos Koutmos

Methyl transfer between methyltetrahydrofolate and corrinoid molecules is a key reaction in biology that is catalyzed by a number of enzymes in many prokaryotic and eukaryotic organisms. One classic example of such an enzyme is cobalamin-dependent methionine synthase (MS). MS is a large modular protein that utilizes an SN2-type mechanism to catalyze the chemically challenging methyl transfer from the tertiary amine (N5) of methyltetrahydrofolate to homocysteine in order to form methionine. Despite over half a century of study, many questions remain about how folate-dependent methyltransferases, and MS in particular, function. Here, the structure of the folate-binding (Fol) domain of MS fromThermus thermophilusis reported in the presence and absence of methyltetrahydrofolate. It is found that the methyltetrahydrofolate-binding environment is similar to those of previously described methyltransferases, highlighting the conserved role of this domain in binding, and perhaps activating, the methyltetrahydrofolate substrate. These structural studies further reveal a new distinct and uncharacterized topology in the C-terminal region of MS Fol domains. Furthermore, it is found that in contrast to the canonical TIM-barrel β8α8fold found in all other folate-binding domains, MS Fol domains exhibit a unique β8α7fold. It is posited that these structural differences are important for MS function.


Nematology ◽  
2009 ◽  
Vol 11 (4) ◽  
pp. 551-554
Author(s):  
Jinu Eo ◽  
Kazunori Otobe

Abstract The objective of this study was to clarify the role of touch sensors in the foraging of Caenorhabditis elegans in a constrained structure. The strains tested included an array of mechanosensory mutants insensitive to touch in the body, tail or nose. The mutants and wild type nematodes repeated forward and backward movement in a micro-moulded substrate as on the surface of agar gel. Differences in the foraging pattern were not obvious among mutant groups having different touch sensor deficit in the substrate, and all strains of nematode successfully moved out of the T-shaped structure after searching the configuration of their environment. The results suggest that the touch sensor is a weak contributor to the performance of the worms when foraging, and the behaviour is governed by intrinsic spontaneous patterns in the absence of any stimuli in natural habitat.


2015 ◽  
Vol 26 (10) ◽  
pp. 1887-1900 ◽  
Author(s):  
Steven D. Garafalo ◽  
Eric S. Luth ◽  
Benjamin J. Moss ◽  
Michael I. Monteiro ◽  
Emily Malkin ◽  
...  

Regulation of glutamate receptor (GluR) abundance at synapses by clathrin-mediated endocytosis can control synaptic strength and plasticity. We take advantage of viable, null mutations in subunits of the clathrin adaptor protein 2 (AP2) complex in Caenorhabditis elegans to characterize the in vivo role of AP2 in GluR trafficking. In contrast to our predictions for an endocytic adaptor, we found that levels of the GluR GLR-1 are decreased at synapses in the ventral nerve cord (VNC) of animals with mutations in the AP2 subunits APM-2/μ2, APA-2/α, or APS-2/σ2. Rescue experiments indicate that APM-2/μ2 functions in glr-1–expressing interneurons and the mature nervous system to promote GLR-1 levels in the VNC. Genetic analyses suggest that APM-2/μ2 acts upstream of GLR-1 endocytosis in the VNC. Consistent with this, GLR-1 accumulates in cell bodies of apm-2 mutants. However, GLR-1 does not appear to accumulate at the plasma membrane of the cell body as expected, but instead accumulates in intracellular compartments including Syntaxin-13– and RAB-14–labeled endosomes. This study reveals a novel role for the AP2 clathrin adaptor in promoting the abundance of GluRs at synapses in vivo, and implicates AP2 in the regulation of GluR trafficking at an early step in the secretory pathway.


2020 ◽  
Vol 57 ◽  
pp. 21-27 ◽  
Author(s):  
Catherine Neumann ◽  
Jessica Baesler ◽  
Gereon Steffen ◽  
Merle Marie Nicolai ◽  
Tabea Zubel ◽  
...  

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