Gyula Hoffmann

Microsatellite markers characterized in the barn owl (Tyto alba) and of high utility in other owls (Strigiformes: AVES)

We have identified 15 polymorphic microsatellite loci for the barn owl (Tyto alba), five from testing published owl loci and 10 from testing non‐owl loci, including loci known to be of high utility in passerines and shorebirds. All 15 loci were sequenced in barn owl, and new primer sets were designed for eight loci. The 15 polymorphic loci displayed two to 26 alleles in 56–58 barn owls. When tested in 10 other owl species (n = 1–6 individuals), between four and nine loci were polymorphic per species. These loci are suitable for studies of population structure and parentage in owls.

Differentially Expressed Epigenome Modifiers, Including Aurora Kinases A and B, in Immune Cells in Rheumatoid Arthritis in Humans and Mouse Models

OBJECTIVE To identify epigenetic factors that are implicated in the pathogenesis of rheumatoid arthritis (RA), and to explore the therapeutic potential of the targeted inhibition of these factors. METHODS Polymerase chain reaction (PCR) arrays were used to investigate the expression profile of genes that encode key epigenetic regulator enzymes. Mononuclear cells from RA patients and mice were monitored for gene expression changes, in association with arthritis development in murine models of RA. Selected genes were further characterized by quantitative reverse transcription-PCR, Western blot, and flow cytometry methods. The targeted inhibition of the up-regulated enzymes was studied in arthritic mice. RESULTS A set of genes with arthritis-specific expression was identified by the PCR arrays. Aurora kinases A and B, both of which were highly expressed in arthritic mice and treatment-naive RA patients, were selected for detailed analysis. Elevated aurora kinase expression was accompanied by increased phosphorylation of histone H3, which promotes proliferation of T lymphocytes. Treatment with VX-680, a pan-aurora kinase inhibitor, promoted B cell apoptosis, provided significant protection against disease onset, and attenuated inflammatory reactions in arthritic mice. CONCLUSION Arthritis development is accompanied by changes in expression of a number of epigenome-modifying enzymes. Drug-induced down-regulation of the aurora kinases, among other targets, seems to be sufficient to treat experimental arthritis. Development of new therapeutics that target aurora kinases can potentially improve RA management.

H Protein of Bacteriophage 16-3 and RkpM Protein of Sinorhizobium meliloti 41 Are Involved in Phage Adsorption

The strain-specific capsular polysaccharide KR5 antigen of Sinorhizobium meliloti 41 is required both for invasion of the symbiotic nodule and for the adsorption of bacteriophage 16-3. In order to know more about the genes involved in these events, bacterial mutants carrying an altered phage receptor were identified by using host range phage mutants. A representative mutation was localized in the rkpM gene by complementation and DNA sequence analysis. A host range phage mutant isolated on these phage-resistant bacteria was used to identify the h gene, which is likely to encode the tail fiber protein of phage 16-3. The nucleotide sequences of the h gene as well as a host range mutant allele were also established. In both the bacterial and phage mutant alleles, a missense mutation was found, indicating a direct contact between the RkpM and H proteins in the course of phage adsorption. Some mutations could not be localized in these genes, suggesting that additional components are also important for bacteriophage receptor recognition.

Random pairing with respect to plumage coloration in Hungarian Barn Owls (Tyto alba)

Between 1998 and 2000, 64 breeding birds of Barn Owl in Hungary were checked for plumage coloration. No relationship between the colour morphs of partners were found. Thus, coloration does not influence pairing. Zwischen 1998 und 2000 wurde die Gefiederfärbung von 64 Brutpaaren der Schleiereule aus ganz Ungarn untersucht. Zwischen den Gefiederfärbungen der Partner bestand kein Zusammenhang. Die Gefiederfärbung hatte damit keinen Einfluss auf die Partnerwahl

Unexplored Potentials of Epigenetic Mechanisms of Plants and Animals–-Theoretical Considerations

Morphological and functional changes of cells are important for adapting to environmental changes and associated with continuous regulation of gene expressions. Genes are regulated–in part–by epigenetic mechanisms resulting in alternating patterns of gene expressions throughout life. Epigenetic changes responding to the environmental and intercellular signals can turn on/off specific genes, but do not modify the DNA sequence. Most epigenetic mechanisms are evolutionary conserved in eukaryotic organisms, and several homologs of epigenetic factors are present in plants and animals. Moreover, in vitro studies suggest that the plant cytoplasm is able to induce a nuclear reassembly of the animal cell, whereas others suggest that the ooplasm is able to induce condensation of plant chromatin. Here, we provide an overview of the main epigenetic mechanisms regulating gene expression and discuss fundamental epigenetic mechanisms and factors functioning in both plants and animals. Finally, we hypothesize that animal genome can be repro-grammed by epigenetic factors from the plant protoplast.

Philopatry analysis of the great reed warbler (Acrocephalus arundinaceus) based on ringing data in Europe

Ringing databases of the EURING Data Bank and the Hungarian Bird Ringing Centre were analysed in order to investigate the philopatry of the great reed warbler (Acrocephalus arundinaceus) in three European regions. The aim of the study was to find out if there are continent-scale geographic trends in philopatry with respect to the age of the birds. Three clusters were assigned according to their geographic positions: (i) southern part of Europe (Region 1: between 36°–43° latitudes), (ii) middle part of Europe (Region 2: between 43°–49° latitudes) and (iii) northern part of Europe, (Region 3: between 49°–56° latitudes). No significant differences were found between the natal and breeding philopatry in any Regions, except Region 3. The birds ringed as adults in Region 3 were less faithful to their breeding site than those of the other two regions. Natal philopatry of juveniles did not differ between Region 1 and Region 2, but both of them differed in this respect from Region 3. A method for choosing appropriate breeding periods in philopatry studies is also proposed.

A Novel MTHFR Isoform-based Biomarker for RA and SLE

Objective: Disease- and drug-related biomarkers are the basis of personalized medicine by guiding patient-specific clinical decisions. The methylene-tetrahydrofolate reductase (MTHFR) gene-associated C677T polymorphism has garnered particular attention because it can lead to an amino acid change resulting in a catalytically compromised enzyme. Here, we provide an alternative interpretation of C677T-associated MTHFR phenotypes that does not exclude the original hypothesis but rather places it in a different context. Our duon-based theory has practical implications as it facilitates the development of a new predictive biomarker for Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE).Methods: The new MTHFR promoter was identified using the 5’RACE method and functionally characterized in transient expression studies. Western blotting and confocal microscopy were used to investigate the subcellular localization of MTHFR isoforms. Expression of MTHFR transcript variants was monitored by qRT-PCR and a gene expression index (Li/Si score) was calculated from the Ct values.Results: A new MTHFR isoform was identified, driven by a novel promoter region that overlaps with the site of the C677T polymorphism. Quantitative monitoring of the catalytically active and the catalytically inactive isoforms’ expression revealed that the proportion of MTHFR isoforms could be altered in PBMCs in a disease-specific manner. The calculated Li/Si scores were found to be characteristic for specific subgroups of RA and SLE patients.Conclusion: Differential expression of MTHFR isoforms provides a foundation on which a predictive biomarker (Li/Si score) could be developed for RA and SLE reflecting disease susceptibility and drug response.

Transcription factor Zbtb38 downregulates the expression of anti-inflammatory IL1r2 in mouse model of rheumatoid arthritis

DNA methylation is a decisive regulator of gene expression. Differentially methylated promoters were described in rheumatoid arthritis (RA), but we do not know how these epimutations can trigger a proinflammatory cytokine milieu. B cell-focused DNA methylome studies identified a group of genes that had undergone disease-associated changes in a murine model of RA. An arthritis-specific epimutation (hypomethylation) was detected in the promoter region of the Zbtb38 gene, which encodes a transcriptional repressor. Gene expression studies revealed that hypomethylation of the Zbtb38 promoter was accompanied by disease-specific repressor expression, and two anti-inflammatory factors interleukin 1 receptor 2 gene (IL1r2) and interleukin-1 receptor antagonist (IL1rn) were among the downregulated genes. We hypothesized that Zbtb38 repressor could induce downregulated expression of these anti-inflammatory genes and that this could significantly contribute to arthritis pathogenesis. Our studies demonstrate that Zbtb38 forms a molecular bridge between an arthritis-associated epimutation (DNA hypomethylation in Zbtb38 promoter) and transcriptional silencing of the IL1r2 gene in B cells. In this way, disease-associated DNA hypomethylation can support autoimmune arthritis by interfering with an anti-inflammatory pathway.

Developmentally regulated autophagy is required for eye formation in Drosophila.

ABSTRACT The compound eye of the fruit fly Drosophila melanogaster is one of the most intensively studied and best understood model organs in the field of developmental genetics. Herein we demonstrate that autophagy, an evolutionarily conserved selfdegradation process of eukaryotic cells, is essential for eye development in this organism. Autophagic structures accumulate in a specific pattern in the developing eye disc, predominantly in the morphogenetic furrow (MF) and differentiation zone. Silencing of several autophagy genes (Atg) in the eye primordium severely affects the morphology of the adult eye through triggering ectopic cell death. In Atg mutant genetic backgrounds however genetic compensatory mechanisms largely rescue autophagic activity in, and thereby normal morphogenesis of, this organ. We also show that in the eye disc the expression of a key autophagy gene, Atg8a, is controlled in a complex manner by the anterior Hox paralog Lab (Labial), a master regulator of early development. Atg8a transcription is repressed in front of, while activated along, the MF by Lab. The amount of autophagic structures then remains elevated behind the moving MF. These results indicate that eye development in Drosophila depends on the cell death-suppressing and differentiating effects of the autophagic process. This novel, developmentally regulated function of autophagy in the morphogenesis of the compound eye may shed light on a more fundamental role for cellular self-digestion in differentiation and organ formation than previously thought. Abbreviations: αTub84B, α-Tubulin at 84B; Act5C, Actin5C; AO, acridine orange; Atg, autophagy-related; Ato, Atonal; CASP3, caspase 3; Dcr-2; Dicer-2; Dfd, Deformed; DZ, differentiation zone; eGFP, enhanced green fluorescent protein; EM, electron microscopy; exd, extradenticle; ey, eyeless; FLP, flippase recombinase; FRT, FLP recognition target; Gal4, gene encoding the yeast transcription activator protein GAL4; GFP, green fluorescent protein; GMR, Glass multimer reporter; Hox, homeobox; hth, homothorax; lab, labial; L3F, L3 feeding larval stage; L3W, L3 wandering larval stage; lf, loss-of-function; MAP1LC3, microtubule-associated protein 1 light chain 3; MF, morphogenetic furrow; PE, phosphatidylethanolamine; PBS, phosphate-buffered saline; PI3K/PtdIns3K, class III phosphatidylinositol 3-kinase; PZ, proliferation zone; Ref(2)P, refractory to sigma P, RFP, red fluorescent protein; RNAi, RNA interference; RpL32, Ribosomal protein L32; RT-PCR, reverse transcription-coupled polymerase chain reaction; S.D., standard deviation; SQSTM1, Sequestosome-1, Tor, Target of rapamycin; TUNEL, terminal deoxynucleotidyl transferase mediated dUTP nick end labeling assay; UAS, upstream activation sequence; qPCR, quantitative real-time polymerase chain reaction; w, white

Demographic decline and detection of genetic bottleneck in a population of Barn Owl Tyto alba in Hungary

AbstractThe effects of population bottlenecks, from both the population and conservation genetics point of view, have attracted great interest. Heterozygosity and allelic diversity are basic components of the evolutionary potential of populations. Many endangered species go through bottlenecks from time to time. The consequences are important because in the resulting small populations the stochastic processes are more pronounced and, by strengthening each other, they can lead to extinction. Within the framework of the global climate change the question emerges of how the different species, primarily susceptible ones and those depending on protection measures, react to the climate extremities. It is well known that a large proportion of Barn Owl Tyto alba populations die following an unfavourable period. In the study reported here we genotyped 24 microsatellite loci of 58 unrelated Barn Owl individuals originating from a continuous population of three neighbouring Hungarian counties. We then performed the Wilcoxon sign-rank test, the L test and Monte Carlo simulation of the loss of alleles and heterozygosity. We also attempted to infer past population dynamics using two likelihood-based Bayesian methods. Although a 74% reduction of this population is well documented following the harsh winter of 2002/2003 and the sampling and resolution of the methods used are standard and considered to be commonly satisfactory, none of the tests showed pronounced signs of a recent bottleneck. These results are discussed in terms of the imminent and apparent drawbacks of the models and methods used, the roles of absolute numbers of survivors versus genotype percentages and the conservation biological viewpoint.ZusammenfassungDemografische Verluste und Nachweis eines genetischen Flaschenhalses in einer Population von SchleiereulenTyto albain Ungarn Sowohl vom populationsgenetischen Standpunkt als auch von dem der Artenschutzgenetik aus ist die Untersuchung von Flaschenhalseffekten von großem Interesse. Heterozygotie und Alleldiversität sind grundlegende Bestandteile des evolutionären Potenzials von Populationen. Viele gefährdete Arten durchlaufen von Zeit zu Zeit einen Flaschenhals. Die Folgen sind von Bedeutung, da in den daraus resultierenden kleinen Populationen stochastische Prozesse stärkeres Gewicht haben und durch sich gegenseitiges Verstärken zum Aussterben führen können. Im Hinblick auf den globalen Klimawandel stellt sich die Frage, wie verschiedene Arten, speziell die sensiblen und solche, die von Schutzmaßnahmen abhängig sind, auf klimatische Extreme reagieren. Von Schleiereulen ist allgemein bekannt, dass nach einer Phase schlechter Bedingungen ein großer Teil der Population stirbt. 58 nicht verwandte Individuen dieser Art aus einer zusammenhängenden Population in drei benachbarten ungarischen Kreisen wurden für 24 Mikrosatelliten-Loci genotypisch charakterisiert. Wir führten einen „Wilcoxon-Vorzeichen-Rang-Test“ und einen L Test sowie eine Monte Carlo-Simulation für den Verlust von Allelen und Heterozygotie durch. Mittels zweier wahrscheinlichkeitsbasierter Bayes-Methoden versuchten wir zudem, Rückschlüsse auf die vergangene Populationsdynamik zu ziehen. Obwohl Populationsverluste von 74% im Winter von 2002/2003 gut dokumentiert sind und die Probennahme sowie die Auflösung der verwendeten Methoden zum gängigen Standard gehören und gemeinhin als zufriedenstellend gelten, zeigte keiner der Tests deutliche Hinweise auf einen kürzlich durchlaufenen Flaschenhals. Wir diskutieren die immanenten und scheinbaren Nachteile der verwendeten Modelle und Methoden, die jeweilige Rolle der absoluten Überlebendenzahlen im Unterschied zu Genotyp-Prozentanteilen sowie den Artenschutzaspekt der Ergebnisse.