Osman El-Maarri

Summary

Affiliation: University of Bonn
Country: Germany

Publications

  1. ncbi request reprint Methods: DNA methylation
    Osman El-Maarri
    Institute of experimental heamatology and transfusion medecine, Sigmund Freud strs 25, 53127 Bonn
    Adv Exp Med Biol 544:197-204. 2003
  2. ncbi request reprint SIRPH analysis: SNuPE with IP-RP-HPLC for quantitative measurements of DNA methylation at specific CpG sites
    Osman El-Maarri
    Institute of Experimental Haematology and Transfusion Medicine, Bonn, Germany
    Methods Mol Biol 287:195-205. 2004
  3. doi request reprint A systematic search for DNA methyltransferase polymorphisms reveals a rare DNMT3L variant associated with subtelomeric hypomethylation
    Osman El-Maarri
    Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Bonn, Germany
    Hum Mol Genet 18:1755-68. 2009
  4. ncbi request reprint Gender specific differences in levels of DNA methylation at selected loci from human total blood: a tendency toward higher methylation levels in males
    Osman El-Maarri
    Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Sigmund Freud Str 25, 53127, Bonn, Germany
    Hum Genet 122:505-14. 2007
  5. pmc Methylation at global LINE-1 repeats in human blood are affected by gender but not by age or natural hormone cycles
    Osman El-Maarri
    Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Bonn, Germany
    PLoS ONE 6:e16252. 2011
  6. ncbi request reprint Familial hydatidiform molar pregnancy: the germline imprinting defect hypothesis?
    O El-Maarri
    Institute of Experimental Hematology and Transfusion Medicine, Bonn, Germany
    Curr Top Microbiol Immunol 301:229-41. 2006
  7. ncbi request reprint Lack of F8 mRNA: a novel mechanism leading to hemophilia A
    Osman El-Maarri
    Institute of Experimental Hematology and Transfusion Medicine, Sigmund Freud Str 25, 53127 Bonn, Germany
    Blood 107:2759-65. 2006
  8. ncbi request reprint DNA methylation and human diseases
    Osman El-Maarri
    Institute of Experimental Haematology and Transfusion Medicine, Sigmund Freud Str 25, 53127 Bonn, Germany
    Adv Exp Med Biol 544:135-44. 2003
  9. pmc A rapid, quantitative, non-radioactive bisulfite-SNuPE- IP RP HPLC assay for methylation analysis at specific CpG sites
    Osman El-Maarri
    Institute of Experimental Haematology and Transfusion Medicine, Sigmund Freud Strasse 25, 53105 Bonn, Germany
    Nucleic Acids Res 30:e25. 2002
  10. ncbi request reprint Patients with familial biparental hydatidiform moles have normal methylation at imprinted genes
    Osman El-Maarri
    Institute of Experimental Haematology and Transfusion Medicine, Bonn, Germany
    Eur J Hum Genet 13:486-90. 2005

Collaborators

Detail Information

Publications27

  1. ncbi request reprint Methods: DNA methylation
    Osman El-Maarri
    Institute of experimental heamatology and transfusion medecine, Sigmund Freud strs 25, 53127 Bonn
    Adv Exp Med Biol 544:197-204. 2003
  2. ncbi request reprint SIRPH analysis: SNuPE with IP-RP-HPLC for quantitative measurements of DNA methylation at specific CpG sites
    Osman El-Maarri
    Institute of Experimental Haematology and Transfusion Medicine, Bonn, Germany
    Methods Mol Biol 287:195-205. 2004
    ..The ratio of the ddCTP to the ddTTP gives the fraction of the methylated cytosines at that specific CpG site...
  3. doi request reprint A systematic search for DNA methyltransferase polymorphisms reveals a rare DNMT3L variant associated with subtelomeric hypomethylation
    Osman El-Maarri
    Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Bonn, Germany
    Hum Mol Genet 18:1755-68. 2009
    ....
  4. ncbi request reprint Gender specific differences in levels of DNA methylation at selected loci from human total blood: a tendency toward higher methylation levels in males
    Osman El-Maarri
    Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Sigmund Freud Str 25, 53127, Bonn, Germany
    Hum Genet 122:505-14. 2007
    ..This observed difference could be due to the process of X chromosome inactivation or merely to the presence of an additional X chromosome in female cells or could be a result of downstream effects of sex determination...
  5. pmc Methylation at global LINE-1 repeats in human blood are affected by gender but not by age or natural hormone cycles
    Osman El-Maarri
    Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Bonn, Germany
    PLoS ONE 6:e16252. 2011
    ..In conclusion, neither natural cycle of hormones nor age has a detectable effect on the LINE-1 methylation in peripheral blood cells, while gender remains an important factor...
  6. ncbi request reprint Familial hydatidiform molar pregnancy: the germline imprinting defect hypothesis?
    O El-Maarri
    Institute of Experimental Hematology and Transfusion Medicine, Bonn, Germany
    Curr Top Microbiol Immunol 301:229-41. 2006
    ..In this chapter, we summarize what is known about methylation aberrations in HMs and examine more closely the proposed hypothesis of a maternal germline imprinting defect...
  7. ncbi request reprint Lack of F8 mRNA: a novel mechanism leading to hemophilia A
    Osman El-Maarri
    Institute of Experimental Hematology and Transfusion Medicine, Sigmund Freud Str 25, 53127 Bonn, Germany
    Blood 107:2759-65. 2006
    ..These findings strongly suggest that the cause of HA in this patient is either absence or rapid degradation of the F8 mRNA, which points to a novel mechanism leading to HA...
  8. ncbi request reprint DNA methylation and human diseases
    Osman El-Maarri
    Institute of Experimental Haematology and Transfusion Medicine, Sigmund Freud Str 25, 53127 Bonn, Germany
    Adv Exp Med Biol 544:135-44. 2003
  9. pmc A rapid, quantitative, non-radioactive bisulfite-SNuPE- IP RP HPLC assay for methylation analysis at specific CpG sites
    Osman El-Maarri
    Institute of Experimental Haematology and Transfusion Medicine, Sigmund Freud Strasse 25, 53105 Bonn, Germany
    Nucleic Acids Res 30:e25. 2002
    ..The assay is linear, highly reproducible and several sites can be measured simultaneously in one reaction. It can be semi-automated and eliminates the need for cloning and sequencing of individual bisulfite PCR products...
  10. ncbi request reprint Patients with familial biparental hydatidiform moles have normal methylation at imprinted genes
    Osman El-Maarri
    Institute of Experimental Haematology and Transfusion Medicine, Bonn, Germany
    Eur J Hum Genet 13:486-90. 2005
    ....
  11. pmc Association of COMT genotypes with S-COMT promoter methylation in growth-discordant monozygotic twins and healthy adults
    Felix Schreiner
    Pediatric Endocrinology Division, Children s Hospital, University of Bonn, Adenauerallee 119, Bonn 53113, Germany
    BMC Med Genet 12:115. 2011
    ..So far, studies investigating the epigenetic variability of the S-COMT (soluble COMT) promoter region mainly focused on phenotypical aspects, and results have been controversial...
  12. ncbi request reprint Maternal alleles acquiring paternal methylation patterns in biparental complete hydatidiform moles
    Osman El-Maarri
    Institute of Experimental Haematology and Transfusion Medicine, Bonn 53105, Germany
    Hum Mol Genet 12:1405-13. 2003
    ..The defective 19q13.4 locus may have led to the development of variable degrees of 'faulty' paternal marks on the maternal chromosomes...
  13. pmc Methylation of L1Hs promoters is lower on the inactive X, has a tendency of being higher on autosomes in smaller genomes and shows inter-individual variability at some loci
    Heike Singer
    Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Bonn, Germany
    Hum Mol Genet 21:219-35. 2012
    ..In summary, loci-specific LINE-1 methylation levels show considerable plasticity and depend on genomic position and constitution...
  14. pmc Measurements of DNA methylation at seven loci in various tissues of CD1 mice
    Laurynas Daugela
    Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Bonn, Germany
    PLoS ONE 7:e44585. 2012
    ..Additional studies that examine large numbers of loci may be required to further understand the factors that influence stability of DNA methylation...
  15. doi request reprint SIRPH: an HPLC-based SNuPE for quantitative methylation measurement at specific CpG sites
    Heike Singer
    Institute of Experimental Haematology and Transfusion Medicine, University of Bonn, Bonn, Germany
    Methods Mol Biol 791:89-100. 2011
    ..This method is highly accurate, reproducible, quantitative, and suitable for analysis of as little as 50 ng of PCR product derived from limited starting materials...
  16. pmc Optimization of quantitative MGMT promoter methylation analysis using pyrosequencing and combined bisulfite restriction analysis
    Thomas Mikeska
    Department of Neuropathology, University of Bonn Medical Center, Sigmund Freud Str 25, D 53105 Bonn, Germany
    J Mol Diagn 9:368-81. 2007
    ..The optimized pyrosequencing assay performed best and provides a sensitive, robust, and easy-to-use method for quantitative assessment of MGMT methylation, for both snap-frozen and paraffin-embedded specimens...
  17. ncbi request reprint Monitoring the progression of the in vitro selection of nucleic acid aptamers by denaturing high-performance liquid chromatography
    Jens Muller
    Institute of Experimental Haematology and Transfusion Medicine, University of Bonn, Sigmund Freud Str 25, 53127, Bonn, Germany
    Anal Bioanal Chem 390:1033-7. 2008
    ..We employ denaturing HPLC and describe for the first time an experimental set-up that is useful both for analysis of the progression of in-vitro selection experiments and for separation of distinct aptamer sequences...
  18. ncbi request reprint New insight into the molecular basis of hemophilia A
    Johannes Oldenburg
    Institute of Experimental Haematology and Transfusion Medicine, Bonn, Germany
    Int J Hematol 83:96-102. 2006
    ..Moreover, the proof of an absence of F8 messenger RNA (mRNA) in one patient points to either a defect in the expression of F8 mRNA or its rapid degradation, which may represent a novel mechanism leading to HA...
  19. doi request reprint Sensitive determination of BRAF copy number in clinical samples by pyrosequencing
    Prashanth Setty
    Department of Neuropathology, University of Bonn, Germany
    Diagn Mol Pathol 20:148-57. 2011
    ..In summary, we have established a pyrosequencing-based assay allowing precise detection of BRAF copy numbers in DNA extracted from clinical samples...
  20. ncbi request reprint Impact of the menstrual cycle on circulating cell-free DNA
    Martin Pölcher
    Department of Gynecology and Obstetrics, Center for Integrated Oncology, Bonn University Medical Center, Sigmund Freud Str 25, D 53105 Bonn, Germany
    Anticancer Res 30:2235-40. 2010
    ..To determine serum levels of circulating cell-free DNA (cfDNA) throughout the stages of endometrial proliferation and apoptosis during the menstrual cycle...
  21. ncbi request reprint Haemophilia A in a female caused by coincidence of a Swyer syndrome and a missense mutation in factor VIII gene
    Ralph M Loreth
    Thromb Haemost 95:747-8. 2006
  22. pmc Epimutations in Prader-Willi and Angelman syndromes: a molecular study of 136 patients with an imprinting defect
    Karin Buiting
    Institut fur Humangenetik, Universitatsklinikum Essen, Essen, Germany
    Am J Hum Genet 72:571-7. 2003
    ..These data suggest that this imprinting defect results from a failure to erase the maternal imprint during spermatogenesis...
  23. ncbi request reprint Epigenetic reprogramming in mouse primordial germ cells
    Petra Hajkova
    Universitat des Saarlandes, FR 8 2 Genetik, Postfach 151150, 66041 Saarbrucken, Germany
    Mech Dev 117:15-23. 2002
    ..Aberrant epigenetic reprogramming in the germ line would cause the inheritance of epimutations that may have consequences for human diseases as suggested by studies on mouse models...
  24. ncbi request reprint DNA-methylation analysis by the bisulfite-assisted genomic sequencing method
    Petra Hajkova
    Max Planck Institute for Molecular Genetics, Berlin, Germany
    Methods Mol Biol 200:143-54. 2002
  25. ncbi request reprint Detection of heterozygous large deletions in the antithrombin gene using multiplex polymerase chain reaction and denatured high performance liquid chromatography
    Anna Pavlova
    Institute of Transfusion Medicine and Immunohaematolgy, DRK Blood Donor Service Baden Württemberg Hessen, 60526 Frankfurt M, Germany
    Haematologica 91:1264-7. 2006
    ..Using this approach we identified heterozygous deletions in four patients: the deletions affected exons 1 and 2, exon 7 and the whole antithrombin gene...
  26. ncbi request reprint Familial molar tissues due to mutations in the inflammatory gene, NALP7, have normal postzygotic DNA methylation
    Ugljesa Djuric
    Departments of Human Genetics and Obstetrics and Gynecology, McGill University Health Center, Montreal, Canada, H3G 1A4
    Hum Genet 120:390-5. 2006
    ..The known role of NALP7 in apoptosis and inflammation pinpoints previously unrecognized pathways that could directly or indirectly underlie the abnormal methylation of imprinted genes in molar tissues...
  27. ncbi request reprint DNA methylation at promoter regions regulates the timing of gene activation in Xenopus laevis embryos
    Irina Stancheva
    Department of Biomedical Sciences, Genes and Development Group, The University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, United Kingdom
    Dev Biol 243:155-65. 2002
    ..Our results suggest that DNA methylation has a role in regulating the timing of gene activation at MBT in Xenopus laevis embryos...