The document discusses epigenetic factors that contribute to imprinting diseases. It describes how epigenetic modifications like DNA and histone methylation establish parental imprints and regulate gene expression in a parent-of-origin specific manner. Alterations in these epigenetic marks can lead to imprinting disorders like Prader-Willi syndrome and Angelman syndrome, which are associated with changes in imprinted genes on chromosome 15. The authors investigate these diseases using methods like MS-PCR to analyze DNA methylation patterns.

1. Epigenetic factors in imprinting diseases Natalia Cucu , PhD, Assisstant Prof, University of Bucharest Gabriela Anton , PhD, Senior Res, Institute of Virology”Stefan Nicolau” Bucharest Maria Puiu , PhD, Professor , UMF Timisoara

5. Key molecule of hereditary information is not free DNA, but rather a complex between DNA and histones called chromatin

7. Relationship between the chromatin structure and the epigenetic (DNA and histone) codes

9. DNA methylation in CpG repetitive sequences

10. Types of methylated deDNA and specific DNA methyltransferases

11. DNA methylation enzymology depends on SAM/SAH ratio and on the exogenous methyl pool provided by folates

12. The main biological role of DNA methylation-transcriptional repression

13. Key points of the histone code represented on the nucleosomal core histones

14. Specific epigenotypes for active and repressed (silenced) chromatin

16. DNA dynamics during reproduction steps (gametogenesis and embryogenesis) is critical for correct imprinting establishment and maintenance

17. Critical stages of DNA methylation process during developmental steps

18. DNA methylation during the imprinting process is controlled by a complex enzymology: there is an interplay between at least known 3 enzymes: DNMT3a/DNMT3b and DNMT3L

20. Erasure and reset of DNA methylation pattern are key processes in correct imprinting process

21. Genes on critical region of Chr15 involved in altered imprinting for PW and A syndromes

23. Classes of genetic and epigenetic alterations in PW and A syndromes

24. Control of allele specific expression is mediated by epigenetic factors (DNA methylation) The influence of the DNA methylation status on the transcriptional activity of the gene affected in the promoter sequences and the proximal exons

25. Alteration of specific allele DNA methylation in PW and A syndromes

28. Principle of the MS-PCR assay for the estimation of the DNAmethylation status in promoter gene regions

29. Normal, AS and PWS electrophoretic patterns after MS-PCR PWS AS

31. METABOLOMIC APPROACH