On the relevance of non-histone proteins to the production of Giemsa banding patterns on chromosomes

Staining properties of a benzimidazol derivative “33258 hoechst” and a simplified staining method for chromosome banding

“…An interaction of DNA-nonhistone protein complex was reported to play an important role on chromosome banding (Comings et al, 1973;Vogel et al, 1974), but "33258 Hoechst" binds to DNA bases and almost not to be affected (Comings, 1975b).…”

Studies on the Mechanism of Chromosome Banding

“…The detailed mechanisms that have been proposed for G-banding all contain a significant role for non-histone protein-DNA interactions Vogel et al, 1974;. This is because most of the histones are extracted from metaphase chromosomes by fixation Brody, 1974;Sivak & Wolman, 1974;Betief & Ruchel, 1977),because variations in chromosome base composition and mass distribution are probably not large enough to account for the contrast observed (Comings et al, 1973), and because there is no evidence of direct interactions of Giemsa dyes with chromosomal proteins .…”

Chromosomes

“…Both authors favour the hypothesis that differences in non-histones cause the differential stability against HCI. CoMINGS et al ( , 1974, RODMAN and TAHILIANI (1973), MEISNER et al (1974), VOGEL et al (1974 and others, favour the hypothesis that the treatments necessary to produce bands themselves (above all the fixation in acetic acidalcohol, the alkali, and the heat treatments) lead to a differential regional association of acid proteins to the DNA and in this way to differential increase in chromosomal condensation. They concluded therefore that histones cannot be responsible for the differential stainability.…”

“…McKAY (1973) and Ross and GORMLEY (1973) reported that the special treatment necessary to produce or enhance banding act first by an alteration of chromatin structure and then by a differential reconstitution. ), MEISNER et al (1973) and VOGEL et al (1974 have pointed out that due to the fixation and other treatments leading to banding, the protein-DNA complexes may be differentially altered and thus produce the staining differences. Giemsa itself may act reconstitutively because of its cationic nature.…”