Modification specifique des bandes Q et R par le 5-bromodeoxyuridine et l'actinomycine D

Abstract

When introduced into human lymphocyte culture, 5-bromodeoxyuridine (BUdR) and actinomycin D (AMD) induce chromosome differentiation by lack of condensation of segments corresponding to Q-bands (BUdR) and R-bands (BUdR and AMD). The total amount of DNA per cell is not modified by these treatments. The non-condensed segments partly keep their properties of R- or Q-banding after heat treatment or staining with quinacrine mustard. On the other hand, they lose their properties after ASG treatment (G-bands), and emit modified fluorescence after staining with acridine orange. With heat treatment or QM staining, it seems that BUdR or AMD elongate the R or Q segments in several ways—homogeneous repartition or fragmentation of various types. On the other hand, this elongation seems homogeneous after Feulgen staining. This suggests that the relation between Feulgen-revealed DNA and substratum of the R- and Q-bands might not be direct.