Asynchronous DNA replication detected by fluorescence in situ hybridisation as a possible indicator of genetic damage in human lymphocytes.
The present study aimed to correlate the DNA replication timing of different genes with genetic damage and frequency of cancer. Using a fluorescence in situ hybridisation (FISH) approach, the replication timing of three loci, two human genes possessing transcriptional capability and involved in both the cellular response to genetic damage and cancer development (TP53 and RB1) and the non-coding locus D22S163, was evaluated. The data obtained show that normal human lymphocytes exposed in vitro to known DNA-damaging agents, e.g. H2O2, ionizing radiation and mitomycin C, exhibit an asynchronous replication of the genes TP53 and RB1. In vivo studies were performed in three different populations from Kazakhstan. In two of these populations that are living in polluted areas and have higher cancer mortalities than people living in a control area, a DNA replication behaviour similar to that observed in human lymphocytes exposed in vitro to known genotoxic agents was detected. The results obtained further indicate that DNA damage hampers replication and FISH represents a fast and accurate method of assessing asynchronous replication by providing an important tool to evaluate DNA damage at a populational level.
Brás
A
A
Department of Genetics, Faculty of Medical Sciences, New University of Lisbon, R. da Junqueira 96, Lisbon, Portugal.
Cotrim
C Z
CZ
Vasconcelos
I
I
Mexia
J
J
Léonard
A
A
Sanzhar
I
I
Akhmatullina
N
N
Rueff
J
J
D004249:DNA Damage; D004261:DNA Replication; D004785:Environmental Pollutants / Q000633:toxicity; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007623:Kazakhstan / Q000453:epidemiology; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D009369:Neoplasms / Q000139:chemically induced / Q000401:mortality*; D011153:Population / Q000235:genetics*; D016160:Retinoblastoma Protein / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
D004785:Environmental Pollutants; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53