ROLE OF DNA PACKAGING ON RARE FRAGILE SITE EXPRESSION Fragile sites classification Gaps, breaks and other chromosome aberrations are induced in cells cultured under specific conditions, generally in the presence of drugs inhibiting or delaying DNA replication. Regions that show a statistically significant increase in the frequency of such abnormalities, above that occurring by chance throughout the human genome, are defined as fragile sites (Sutherland et al., 1998). They were first described in 1965 and have been found on every chromosome with the exception of chromosome 21 (Sutherland et al., 1987). In recent years, fragile sites have raised considerable interest, because they appear to participate in chromosomal rearrangements involved in cancer, leukemia, mental retardation and aging (LeBeau and Rowley, 1984; Smith et al., 1998; Yunis and Soreng, 1984). Fragile sites are classified into two categories, rare and common or constitutive, depending on the frequency observed in the population and on the cell culture conditions inducing their expression. The 28 rare fragile sites are carried by less than 5% of the human population; they segregate in a Mendelian manner and are associate with CGG or AT repeats (Kremer et al., 1991; Sutherland et al., 1998). The majority of them are induced by a decrease in the concentration of folic acid and/or thymidine in the culture medium. Other rare fragile sites can be induced by distamycin A or bromodeoxyuridine (BrdU). The 89 common fragile sites, so far detected, are expressed constitutively in all individuals, and most of them (75 according to Genome Data Base) are induced by aphidicolin (Glover et al., 1984), a drug which inhibits DNA polymerases and , while other sites are induced by 5-azacytidine or BrdU .
Role of DNA packaging on rare fragile site expression.
MORELLI, Cristina;TOGNON, Mauro;
2006
Abstract
ROLE OF DNA PACKAGING ON RARE FRAGILE SITE EXPRESSION Fragile sites classification Gaps, breaks and other chromosome aberrations are induced in cells cultured under specific conditions, generally in the presence of drugs inhibiting or delaying DNA replication. Regions that show a statistically significant increase in the frequency of such abnormalities, above that occurring by chance throughout the human genome, are defined as fragile sites (Sutherland et al., 1998). They were first described in 1965 and have been found on every chromosome with the exception of chromosome 21 (Sutherland et al., 1987). In recent years, fragile sites have raised considerable interest, because they appear to participate in chromosomal rearrangements involved in cancer, leukemia, mental retardation and aging (LeBeau and Rowley, 1984; Smith et al., 1998; Yunis and Soreng, 1984). Fragile sites are classified into two categories, rare and common or constitutive, depending on the frequency observed in the population and on the cell culture conditions inducing their expression. The 28 rare fragile sites are carried by less than 5% of the human population; they segregate in a Mendelian manner and are associate with CGG or AT repeats (Kremer et al., 1991; Sutherland et al., 1998). The majority of them are induced by a decrease in the concentration of folic acid and/or thymidine in the culture medium. Other rare fragile sites can be induced by distamycin A or bromodeoxyuridine (BrdU). The 89 common fragile sites, so far detected, are expressed constitutively in all individuals, and most of them (75 according to Genome Data Base) are induced by aphidicolin (Glover et al., 1984), a drug which inhibits DNA polymerases and , while other sites are induced by 5-azacytidine or BrdU .I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
