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Interaction Profiling Identifies the Human Nuclear Exosome Targeting Complex
Get PDFThe RNA exosome is a conserved degradation machinery,which obtains full activity only when associated with cofactors. The most prominent activator of the yeast nuclear exosome is the RNA helicase Mtr4p, acting in the context of the Trf4p/Air2p/Mtr4p polyadenylation (TRAMP) complex. The existence of a similar activator(s) in humans remains
elusive. By establishing an interaction network of the human nuclear exosome, we identify the trimeric Nuclear Exosome Targeting (NEXT) complex, containing hMTR4, the Zn-knuckle protein ZCCHC8, and the putative RNA binding protein RBM7. ZCCHC8 and RBM7 are excluded from nucleoli, and consistently NEXT is specifically required for the exosomal degradation of promoter upstream transcripts
(PROMPTs). We also detect putative homolog
TRAMP subunits hTRF4-2 (Trf4p) and ZCCHC7 (Air2p) in hRRP6 and hMTR4 precipitates. However, at least ZCCHC7 function is restricted to nucleoli. Our results suggest that human nuclear exosome degradation pathways comprise modules of spatially organized cofactors that diverge from the yeast
model
Human ELAC2 gene encodes the tRNAseZ responsible for mitochondrial tRNA 3’ processing which acts on precursors already cleaved by RNAseP
Get PDFAccurate tRNA processing is crucial for human mitochondrial genome expression, but the mechanisms and key enzymes involved are poorly characterized. Here we demonstrate for the first time that human protein ELAC2 localizes both in mitochondria and the nucleus. Using the RNAi gene silencing in HeLa cells we show that the ELAC2 gene encodes tRNAseZ endonuclease which is responsible for the mitochondrial tRNA 3' processing in vivo. In addition we demonstrate that the order of precursor cleavage in mitochondria follows the rule that tRNase Z can only cleave molecules already processed by RNase P
Osteoprotegerin gene polymorphism in diabetic Charcot neuroarthropathy
Get PDFAims: Recently, an association between two polymorphisms (1181G>C and 245T>G) of the osteoprotegerin (OPG) gene and
diabetic Charcot neuroarthropathy was suggested on the basis of studies of a limited number of samples derived from subjects from one geographical region (Italy). The aim of this study was to assess the presence of various osteoprotegerin gene polymorphisms in patients with diabetes and Charcot neuroarthropathy compared with subjects with diabetic neuropathy but no Charcot foot and healthy controls from another geographical region (Poland).
Methods: DNA was isolated from 54 patients with Charcot neuroarthropathy, 35 subjects with diabetic neuropathy but no Charcot foot, and 95 healthy controls to evaluateOPGgene polymorphisms and their possible contribution to the development of Charcot neuroarthropathy.
Results: Statistically significant differences between the group of subjects with neuropathy but no Charcot neuroarthropathy and the control group were found for 1217C>T, 950T>C and 245T>G polymorphisms, between the group of patients with Charcot neuroarthropathy and the control group for 1181G>Cand 950T>Cpolymorphisms, and between the group of subjects with neuropathy but no Charcot neuroarthropathy and the group of patients withCharcot neuroarthropathy for 1217C>T and 245T>G polymorphisms.
Conclusion: We suggest that genetic factors, particularly OPG gene polymorphisms, may play a role in the development of diabetic Charcot neuroarthropathy
Effects of myosin heavy chain (MHC) plasticity induced by HMGCoA-reductase inhibition on skeletal muscle functions.
Get PDFThe rate-limiting step of cholesterol biosynthetic pathway is catalyzed by 3-hydroxy-3-methylglutaryl coenzyme reductase (HGMR), whose inhibitors, the statins, widely used in clinical practice to treat hypercholesterolemia, often cause myopathy, and rarely rhabdomyolysis. All studies to date are limited to the definition of statin-induced myotoxicity omitting to investigate whether and how HMGR inhibition influences muscle functions. To this end, 3-mo-old male rats (Rattus norvegicus) were treated for 3 wk with a daily intraperitoneal injection of simvastatin (1.5 mg/kg/d), and biochemical, morphological, mechanical, and functional analysis were performed on extensor digitorum longus (EDL) muscle. Our results show that EDL muscles from simvastatin-treated rats exhibited reduced HMGR activity; a 15% shift from the fastest myosin heavy-chain (MHC) isoform IIb to the slower IIa/x; and reduced power output and unloaded shortening velocity, by 41 and 23%, respectively, without any change in isometric force and endurance. Moreover, simvastatin-treated rats showed a decrease of maximum speed reached and the latency to fall off the rotaroad (∼-30%). These results indicate that the molecular mechanism of the impaired muscle function following statin treatment could be related to the plasticity of fast MHC isoform expression
Functional gene expression profile underlying methotrexate-induced senescence in human colon cancer cells.
No full textCellular functions accompanying establishment of premature senescence in methotrexate-treated human colon cancer C85 cells are deciphered in the present study from validated competitive expression microarray data, analyzed with the use of Ingenuity Pathways Analysis (IPA) software. The nitrosative/oxidative stress, inferred from upregulated expression of inducible nitric oxide synthase (iNOS) and mitochondrial dysfunction-associated genes, including monoamine oxidases MAOA and MAOB, β-amyloid precursor protein (APP) and presenilin 1 (PSEN1), is identified as the main determinant of signaling pathways operating during senescence establishment. Activation of p53-signaling pathway is found associated with both apoptotic and autophagic components contributing to this process. Activation of nuclear factor κB (NF-κB), resulting from interferon γ (IFNγ), integrin, interleukin 1β (IL-1β), IL-4, IL-13, IL-22, Toll-like receptors (TLRs) 1, 2 and 3, growth factors and tumor necrosis factor (TNF) superfamily members signaling, is found to underpin inflammatory properties of senescent C85 cells. Upregulation of p21-activated kinases (PAK2 and PAK6), several Rho molecules and myosin regulatory light chains MYL12A and MYL12B, indicates acquisition of motility by those cells. Mitogen-activated protein kinase p38 MAPK β, extracellular signal-regulated kinases ERK2 and ERK5, protein kinase B AKT1, as well as calcium, are identified as factors coordinating signaling pathways in senescent C85 cells
Evolution of apoptosis-like programmed cell death in unicellular protozoan parasites
Get PDFApoptosis-like programmed cell death (PCD) has recently been described in multiple taxa of unicellular protists, including the protozoan parasites Plasmodium, Trypanosoma and Leishmania. Apoptosis-like PCD in protozoan parasites shares a number of morphological features with programmed cell death in multicellular organisms. However, both the evolutionary explanations and mechanisms involved in parasite PCD are poorly understood. Explaining why unicellular organisms appear to undergo 'suicide' is a challenge for evolutionary biology and uncovering death executors and pathways is a challenge for molecular and cell biology. Bioinformatics has the potential to integrate these approaches by revealing homologies in the PCD machinery of diverse taxa and evaluating their evolutionary trajectories. As the molecular mechanisms of apoptosis in model organisms are well characterised, and recent data suggest similar mechanisms operate in protozoan parasites, key questions can now be addressed. These questions include: which elements of apoptosis machinery appear to be shared between protozoan parasites and multicellular taxa and, have these mechanisms arisen through convergent or divergent evolution? We use bioinformatics to address these questions and our analyses suggest that apoptosis mechanisms in protozoan parasites and other taxa have diverged during their evolution, that some apoptosis factors are shared across taxa whilst others have been replaced by proteins with similar biochemical activities
Recombinant Cytokines from Plants
Get PDFPlant-based platforms have been successfully applied for the last two
decades for the efficient production of pharmaceutical proteins. The number of commercialized products biomanufactured in plants is, however, rather discouraging. Cytokines are small glycosylated polypeptides used in the treatment of cancer, immune disorders and various other related diseases. Because the clinical use of cytokines is limited by high production costs they are good candidates for plant-made pharmaceuticals. Several research groups explored the possibilities of cost-effective production of animal cytokines in plant systems. This review summarizes recent advances in this field
8-Oxoguanine incision activity is impaired in lung tissues of NSCLC patients with the polymorphism of OGG1 and XRCC1 genes
Get PDFDecreased repair of oxidative DNA damage is a risk factor for developing certain human malignancies. We have previously found that the capacity of 8-oxo-7,8-dihydroguanine repair was lower in leukocytes of NSCLC patients than in controls. To explain these observations, we searched for mutations and polymorphisms in the OGG1 gene among 88 NSCLC patients and 79 controls. One patient exhibited a heterozygous mutation in exon 1, which resulted in Arg46Gln substitution. Normal lung and tumor tissue carrying this mutation showed markedly lower 8-oxoG incision activity than the mean for all patients. The predominant polymorphism of OGG1 was Ser326Cys. A significant difference was observed in the frequencies of the OGG1 variants between populations of NSCLC patients and controls. The frequency of the Cys326 allele and the number of Cys326Cys homozygotes was higher among patients than controls. In individuals with either Ser326Cys or Cys326Cys genotype 8-oxoG incision rate was lower than in those with both Ser326 alleles, either in lung or leukocytes. Moreover, 8-oxodG level was higher in lung tissue and leukocytes of patients carrying two Cys326 alleles and in leukocytes of patients with the Ser326Cys genotype. We also screened for polymorphisms of the XRCC1 gene. Only heterozygotes of the XRCC1 variants Arg194Trp, Arg280His and Arg399Gln were found among patients and controls, with the frequency of Arg280His being significantly higher among patients. NSCLC patients with Arg280His or Arg399Gln polymorphism revealed lower 8-oxoG incision activity in their lung tissues, but not in leukocytes. We can conclude that the OGG1 Ser326Cys polymorphisms may have an impact on the efficiency of 8-oxoG incision in humans and the XRCC1 His280 and Gln399 may influence the OGG1 activity in tissues exposed to chronic oxidative/inflammatory stress. Higher frequency of the OGG1 Cys326 allele among NSCLC patients may partially explain the impairment of the 8-oxoG repair observed in their leukocytes
Solution NMR structure and dynamics of human apo-S100A1 protein
Get PDFS100A1 belongs to the EF-hand superfamily of calcium binding proteins. It is a representative of the S100
protein family based on amino acid sequence, three-dimensional structure, and biological function as a
calcium signal transmitter. It is a homodimer of noncovalently bound subunits. S100A1, like most of
other members of the S100 protein family, is a multifunctional, regulatory protein involved in a large
variety of biological processes and closely associated with several human diseases. The three-dimensional
structure of human apo-(i.e. calcium free)-S100A1 protein was determined by NMR spectroscopy
(PDB 2L0P) and its backbone dynamics established by 15N magnetic relaxation. Comparison of these
results with the structure and backbone dynamics previously determined for bovine apo-S100A1 protein
modified by disulfide formation with b-mercaptoethanol at Cys 85 revealed that the secondary structure
of both these proteins was almost identical, whereas the global structure of the latter was much more
mobile than that of human apo-S100 protein. Differences between the structures of human and rat
apo-S100A1 are also discussed