Can sister chromatid intercrossings be considered as prelesions?
In a study of the expression of folate-sensitive fragile sites in five normal individuals using RPMI medium containing methotrexate (MTX), we observed a high frequency of "sister chromatid intercrossings" (SCI) that is, the intersection of sister chromatids. The location of SCIs corresponded to fragile sites in 54.2% of the cases. Of the SCIs observed in each individual, 43%-53% were located at the same bands as their expressed fragile sites. Furthermore when RPMI + MTX medium was used instead of F-10 medium, the incidence of SCIs increased tenfold. We suggest that SCIs could indicate the existence of a pre-lesion.
Fuster
C
C
Departament de Biologia Cel.lular i Fisiologia, Facultat de Medicina, Autònoma de Barcelona, Spain.
Mirò
R
R
Templado
C
C
Barrios
L
L
Egozcue
J
J
D002478:Cells, Cultured; D002871:Chromosome Banding; D043283:Chromosome Fragile Sites; D002873:Chromosome Fragility; D005492:Folic Acid / Q000494:pharmacology; D006801:Humans; D007621:Karyotyping; D008214:Lymphocytes / Q000648:ultrastructure; D008727:Methotrexate / Q000494:pharmacology; D012854:Sister Chromatid Exchange
D005492:Folic Acid; D008727:Methotrexate