Avtor/Urednik		Zagradišnik, Boris
Naslov		Hipometilacija alfoidne DNA in klasične satelitne DNA na kromosomih 1, 9, 16 in Y v celicah ekstraembrionalnih tkiv
Tip		monografija
Kraj izdaje		Ljubljana
Založnik		Univerza v Ljubljani, Medicinska fakulteta
Leto izdaje		2000
Obseg		str. 42
Jezik		slo
Abstrakt		Introduction. Regulation of DNA methylation is an elementary process in human genome. The pattern of 5-methylcytosines in normal somatic cells is tissue-specific and meticulously restored after each DNA replication. Both level and pattern of DNA methylation are set during early embryogenesis. After initial global demethylation there is a surge in "de novo" DNA methylation. The final level of DNA methylation is lower in extraembryonic cells and in gamete-progenitor cells than in somatic embryonic tissue. Therefore, analysis of DNA methylation with fluorescein labeled antibody against 5-methylcytosine on metaphase chromosomes shows lower intensities of immunofluorescence in extraembryonic tissue than in normal human lymphocytes. Extraembryonic cells have lower overall immunofluorescence and lower immunofluorescence from centromeric and pericentromeric regions on chromosomes 1, 9, 16 and from heterochromatin on chromosome Y in comparison with lymphocytes which exhibit very bright immunofluorescence. The main components of centromeric and pericentromeric regions of chromosomes are different types of non-coding repetitive DNA (i.e. classical satellite DNA). Hypomethylation of these repetitive sequences can be proposed to explain lower immunofluorescence from heterochromatin of metaphase chromosomes from human extraembryonic tissue. The aim of this study was to detect hipomethylation of alphoid DNA and classical satellite DNA on chromosomes 1, 9, 16 and Y in extraembyonic tissue in comparison with normal human leucocytes using Southern blot method. Also results from immunofluorescence analysis of DNA methylation with antibody against 5 methylcytosine were evaluated. Methods. DNA methylation analysis was performed on DNA from chorionic villi, from placental fibroblasts and from normal adult human leucocytes. Methylation sensitive restriction enzymes were used for Southern blot analysis of DNA methylation. Results. (Abstract truncated at 2000 characters.)
Deskriptorji		DNA METHYLATION CHROMOSOMES, HUMAN, PAIR 1 CHROMOSOMES, HUMAN, PAIR 9 CHROMOSOMES, HUMAN, PAIR 16 Y CHROMOSOME DNA, SATELLITE LEUKOCYTES BLOTTING, SOUTHERN CYTOSINE CHORIONIC VILLI FLUORESCENT ANTIBODY TECHNIQUE POLYMERASE CHAIN REACTION