Study of X chromosome DNA methylation status in human reproduction

The purpose of this study was to examine the effect of DNA methylation on human reproduction. Our study included three groups of patients: Greek women with unexplained recurrent miscarriage (Group A), infertile men who will undergo in vitro fertilization procedure (Group B) and girls bornt after in vitro fertilization procedure and preimplantation genetic diagnosis (Group C). Group A methylation analysis demonstrate that there is association between recurrent miscarriage and skewed X-chromosome inactivation. Group C methylation analysis didn’t show any relation between those two phenomena. Finally, study of group B revealed that HUNARA and SNRPN genes can be used as molecular markers so as to examine the presence at germ cells in human testicular samples.Στόχος της παρούσης εργασίας ήταν η μελέτη του φαινόμενου της μεθυλίωσης του DNA στην ανθρώπινη αναπαραγωγή. Η μελέτη μας περιελάμβανε τις εξής ομάδες πληθυσμών: γυναίκες με καθέξιν αποβολές (Α), άνδρες με προβλήματα υπογονιμότητας που κατέφυγαν σε τεχνικές υποβοηθούμενης αναπαραγωγής (Β) και κορίτσια που γεννήθηκαν μετά από προεμφυτευτική γενετική διάγνωση (Γ). Όσον αφορά στην ομάδα (Α) στόχος μας να ελέγχουμε εάν το διαταραγμένο πρότυπο μεθυλίωσης του χρωμοσώματος Χ σχετίζεται με τις καθέξιν αποβολές. Πράγμα που βρέθηκε ότι ισχύει, όχι όμως και για κορίτσια με προεμφυτευτική διάγνωση. (Γ ομάδα). Η μελέτη της ομάδας (Γ) έδειξε ότι τα γονίδια HUNARA και SNRPN μπορούν να χρησιμοποιηθούν ως μοριακοί δείκτες στο DNA αρχικού ιστού για την ένδειξη περιεκτικότητας σε γαμετικά κύτταρα

Allelic imbalance of expression and epigenetic regulation within the alpha-synuclein wild-type and p.Ala53Thr alleles in Parkinson disease

Genetic alterations in the alpha-synuclein (SNCA) gene have been implicated in Parkinson Disease (PD), including point mutations, gene multiplications, and sequence variations within the promoter. Such alterations may be involved in pathology through structural changes or overexpression of the protein leading to protein aggregation, as well as through impaired gene expression. It is, therefore, of importance to specify the parameters that regulate SNCA expression in its normal and mutated state. We studied the expression of SNCA alleles in a lymphoblastoid cell line and in the blood cells of a patient heterozygous for p.Ala53Thr, the first mutation to be implicated in PD pathogenesis. Here, we provide evidence that: (1) SNCA shows monoallelic expression in this patient, (2) epigenetic silencing of the mutated allele involves histone modifications but not DNA methylation, and (3) steady-state mRNA levels deriving from the normal SNCA allele in this patient exceed those of the two normal SNCA alleles combined, in matching, control individuals. An imbalanced SNCA expression in this patient is thus documented, with silencing of the p.Ala53Thr allele and upregulation of the wild-type-allele. This phenomenon is demonstrated for a first time in the SNCA gene, and may have important implications for PD pathogenesis