Human PrimPol mutation associated with high myopia has a DNA replication defect

PrimPol is a primase-polymerase found in humans, and other eukaryotes, involved in bypassing lesions encountered during DNA replication. PrimPol employs both translesion synthesis and repriming mechanisms to facilitate lesion bypass by the replisome. PrimPol has been reported to be a potential susceptibility gene associated with the development of myopia. Mutation of tyrosine 89 to aspartic acid (PrimPolY89D) has been identified in a number of cases of high myopia, implicating it in the aetiology of this disorder. Here, we examined whether this mutation resulted in any changes in the molecular and cellular activities associated with human PrimPol. We show that PrimPolY89D has a striking decrease in primase and polymerase activities. The hydrophobic ring of tyrosine is important for retaining wild-type extension activity. We also demonstrate that the decreased activity of PrimPolY89D is associated with reduced affinities for DNA and nucleotides, resulting in diminished catalytic efficiency. Although the structure and stability of PrimPolY89D is altered, its fidelity remains unchanged. This mutation also reduces cell viability after DNA damage and significantly slows replication fork rates in vivo. Together, these findings establish that the major DNA replication defect associated with this PrimPol mutant is likely to contribute to the onset of high myopia

Inhibition of Chk1 Kills Tetraploid Tumor Cells through a p53-Dependent Pathway

Tetraploidy constitutes an adaptation to stress and an intermediate step between euploidy and aneuploidy in oncogenesis. Tetraploid cells are particularly resistant against genotoxic stress including radiotherapy and chemotherapy. Here, we designed a strategy to preferentially kill tetraploid tumor cells. Depletion of checkpoint kinase-1 (Chk1) by siRNAs, transfection with dominant-negative Chk1 mutants or pharmacological Chk1 inhibition killed tetraploid colon cancer cells yet had minor effects on their diploid counterparts. Chk1 inhibition abolished the spindle assembly checkpoint and caused premature and abnormal mitoses that led to p53 activation and cell death at a higher frequency in tetraploid than in diploid cells. Similarly, abolition of the spindle checkpoint by knockdown of Bub1, BubR1 or Mad2 induced p53-dependent apoptosis of tetraploid cells. Chk1 inhibition reversed the cisplatin resistance of tetraploid cells in vitro and in vivo, in xenografted human cancers. Chk1 inhibition activated p53-regulated transcripts including Puma/BBC3 in tetraploid but not in diploid tumor cells. Altogether, our results demonstrate that, in tetraploid tumor cells, the inhibition of Chk1 sequentially triggers aberrant mitosis, p53 activation and Puma/BBC3-dependent mitochondrial apoptosis

Subsurface life can modify volatile cycling on a planetary scale

The past decade of environmental microbiology has revealed that subsurface environments, both marine and continental, harbor one of the largest ecosystems of our planet, with diversity and biomass rivaling those of the surface. In addition, subsurface life has been recently shown to contribute significantly to the planet’s biogeochemistry, with microbial activity potentially playing an important role in controlling the flux and composition of volatiles recycled between the Earth’s surface and interior, which has broad implications for the search for life beyond our planet. Current efforts to discover extraterrestrial life are focused on planetary bodies with largely inhospitable surfaces, such as Mars, Venus, Europa, Titan, and Enceladus. In these locations, subsurface environments might provide niches of habitability, making the study of deep microbial life a priority for future astrobiological missions. Understanding how volatile elements are exchanged between planetary surfaces and interiors and the role of a subsurface biosphere in altering their composition and flux might provide a tractable target for defining planetary habitability and the detection of subsurface life forms.Fil: Giovanelli, D.. Università degli Studi di Napoli Federico II; Italia. Tokyo Institute of Technology; Japón. Rutgers University; Estados Unidos. Consiglio Nazionale delle Ricerche; Italia. Woods Hole Oceanographic Institution; Estados UnidosFil: Barry, P. H.. Woods Hole Oceanographic Institution; Estados UnidosFil: Bekaert, D. V.. Woods Hole Oceanographic Institution; Estados UnidosFil: Chiodi, Agostina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Cordone, A.. Università degli Studi di Napoli Federico II; ItaliaFil: Covone, G.. Università degli Studi di Napoli Federico II; Italia. Istituto Nazionale di Astrofisica; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Jessen, G.. Universidad Austral de Chile; ChileFil: Lloyd, K.. University of Tennessee; Estados UnidosFil: de Moor, J. M.. Universidad Nacional; Costa RicaFil: Morrison, S. M.. Carnegie Institution For Science; Estados UnidosFil: Schrenk, M. O.. Michigan State University; Estados UnidosFil: Vitale Brovarone, A.. Alma Mater Studiorum Universit`a Di Bologna; Italia. Sorbonne University; Francia. Museum National d’Histoire Naturelle; Franci

Mutations in Thyroid Hormone Beta Receptor Gene Identified in Children with Clinical Resistance to Thyroid Hormones

Introduction: Patients with resistance to thyroid hormones(RTH) show different clinical features. Several mutations have been identified in them.Objective:To describe patients followed up since 2006 with RTH suspicion evaluated for mutations in thyroid hormone beta receptor(THRß)gene.Methods:Children were followed up in our Endocrinology Department.Patient 1:10-yr-old boy with elevated T3, T4 and free T4, normal TSH in routine thyroid testing requested for overweight. Patient 2:0.7-yr- old boy with Down syndrome and elevated T3, T4 and free T4, normal TSH.Patient 3:Boy with abnormal results on neonatal screening, with elevated T3, T4, free T4 and TSH.Patient 4:4.7?yr-old girl with elevated T3, T4 and free T4, normal TSH in routine thyroid testing requested for low weight.Patient 5: 1-yr- old boy with elevated T3, T4 and free T4, normal TSH in routine thyroid testing requested for low weight.Patient 6:Boy with congenital hypothyroidism diagnosed by screening with elevated T3, T4, free T4 and TSH.Clinical manifestations:Patients 1, 4 and 5 showed palpitations, tachycardia.Familial antecedents: Patient 3 has two brothers with similar RTH profile. Patient 4 had a sister who died at 3 months of age and mother with confirmed RTH. Patient 6 had an aunt with RTH profile.Thyroid ultrasound. All patients had normal gland size except patient 6 who had an hypoplastic gland. Patient 4 showed goiter at follow up.Treatment:Patient 1 received metimazol; patients 1,4 and 5 beta blockers and patient 6 levothyroxine.Molecular biology analysis: genomic DNA was isolated from blood cells and the exons 7-10 of the THRß gene, including the flanking intronic regions were amplified by PCR. DNA sequences from each amplified fragment were performed with the Taq polymerase-based chain terminator method and using the specific forward and reverse THRß primers. Results.Direct sequence analysis revealed a novel missense mutation in exon 10 in patient 3, c.1329G>T transvertion that results in a p.K443N substitution and two known missense mutations: c.1357C>A, p.P453T (Patient 1)in exon 10 and c.949G>A, p.A317T (Patient 4) in exon 9.Conclusion:THRß gene mutations were found in half of the patients with RTH, including a new mutation.Although goiter is a common feature in RTH, only one patient presented it.These findings support the importance of searching THRßgene mutations in suspected individuals to achieve an adequate follow-up and treatment in patients with RHT.Fil: Gonzáles, Viviana. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Balbi, Viviana A.. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Morin, Analía. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Reinoso, Andrea. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Vitale, Laura. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Ricci, Jaime. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Espósito, Mariela. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Martín, Rodrigo. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Tournier, Andrea L.. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Adrover, Ezequiela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; ArgentinaFil: Molina, Maricel Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; ArgentinaFil: Targovnik, Hector Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; ArgentinaFil: Rivolta, Carina Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; ArgentinaXXVIII Congreso Latinoamericano de Endocrinología PediátricaFlorianópolisBrasilSociedad Latinoamericana de Endocrinología Pediátric

Cryptic Leishmania infantum infection in Italian HIV infected patients

<p>Abstract</p> <p>Background</p> <p>Visceral leishmaniasis (VL) is a protozoan diseases caused in Europe by <it>Leishmania (L.) infantum</it>. Asymptomatic <it>Leishmania </it>infection is more frequent than clinically apparent disease. Among HIV infected patients the risk of clinical VL is increased due to immunosuppression, which can reactivate a latent infection. The aims of our study were to assess the prevalence of asymptomatic <it>L. infantum </it>infection in HIV infected patients and to study a possible correlation between <it>Leishmania </it>parasitemia and HIV infection markers.</p> <p>Methods</p> <p>One hundred and forty-five HIV infected patients were screened for the presence of anti-<it>Leishmania </it>antibodies and <it>L. infantum </it>DNA in peripheral blood. Statistical analysis was carried out by using a univariate regression analysis.</p> <p>Results</p> <p>Antibodies to <it>L. infantum </it>were detected in 1.4% of patients. <it>L. infantum </it>DNA was detected in 16.5% of patients. Significant association for PCR-<it>Leishmania </it>levels with plasma viral load was documented (p = 0.0001).</p> <p>Conclusion</p> <p>In our area a considerable proportion of HIV infected patients are asymptomatic carriers of <it>L. infantum </it>infection. A relationship between high HIV viral load and high parasitemic burden, possibly related to a higher risk of developing symptomatic disease, is suggested. PCR could be used for periodic screening of HIV patients to individuate those with higher risk of reactivation of <it>L. infantum </it>infection.</p

HIPK2 and extrachromosomal histone H2B are separately recruited by Aurora-B for cytokinesis

Cytokinesis, the final phase of cell division, is necessary to form two distinct daughter cells with correct distribution of genomic and cytoplasmic materials. Its failure provokes genetically unstable states, such as tetraploidization and polyploidization, which can contribute to tumorigenesis. Aurora-B kinase controls multiple cytokinetic events, from chromosome condensation to abscission when the midbody is severed. We have previously shown that HIPK2, a kinase involved in DNA damage response and development, localizes at the midbody and contributes to abscission by phosphorylating extrachromosomal histone H2B at Ser14. Of relevance, HIPK2-defective cells do not phosphorylate H2B and do not successfully complete cytokinesis leading to accumulation of binucleated cells, chromosomal instability, and increased tumorigenicity. However, how HIPK2 and H2B are recruited to the midbody during cytokinesis is still unknown. Here, we show that regardless of their direct (H2B) and indirect (HIPK2) binding of chromosomal DNA, both H2B and HIPK2 localize at the midbody independently of nucleic acids. Instead, by using mitotic kinase-specific inhibitors in a spatio-temporal regulated manner, we found that Aurora-B kinase activity is required to recruit both HIPK2 and H2B to the midbody. Molecular characterization showed that Aurora-B directly binds and phosphorylates H2B at Ser32 while indirectly recruits HIPK2 through the central spindle components MgcRacGAP and PRC1. Thus, among different cytokinetic functions, Aurora-B separately recruits HIPK2 and H2B to the midbody and these activities contribute to faithful cytokinesis

The origin of human pathogenicity and biological interactions in Chaetothyriales

Fungi in the order Chaetothyriales are renowned for their ability to cause human infections. Nevertheless, they are not regarded as primary pathogens, but rather as opportunists with a natural habitat in the environment. Extremotolerance is a major trend in the order, but quite diferent from black yeasts in Capnodiales which focus on endurance, an important additional parameter is advancing toxin management. In the ancestral ecology of rock colonization, the association with metabolite-producing lichens is signifcant. Ant-association, dealing with pheromones and repellents, is another mainstay in the order. The phylogenetically derived family, Herpotrichiellaceae, shows dual ecology in monoaromatic hydrocarbon assimilation and the ability to cause disease in humans and cold-blooded vertebrates. In this study, data on ecology, phylogeny, and genomics were collected and analyzed in order to support this hypothesis on the evolutionary route of the species of Chaetothyriales. Comparing the ribosomal tree with that of enzymes involved in toluene degradation, a signifcant expansion of cytochromes is observed and the toluene catabolism is found to be complete in some of the Herpotrichiellaceae. This might enhance human systemic infection. However, since most species have to be traumatically inoculated in order to cause disease, their invasive potential is categorized as opportunism. Only in chromoblastomycosis, true pathogenicity might be surmised. The criterion would be the possible escape of agents of vertebrate disease from the host, enabling dispersal of adapted genotypes to subsequent generations.info:eu-repo/semantics/publishedVersio

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde