✦ LIBER ✦

Mechanisms of chromosome banding

✍ Scribed by David E. Comings; Evangelita Avelino

Publisher: Springer
Year: 1975
Tongue: English
Weight: 892 KB
Volume: 51
Category: Article
ISSN: 0009-5915
DOI: 10.1007/bf00326323

No coin nor oath required. For personal study only.

✦ Synopsis

The binding of methylene blue to DNA and chromatin treated in various ways was examined by equilibrium dialysis. The maximum r value (moles of bound dye/mole of nucleotide) was 1.0 for DNA, 0.6 for unfixed chromatin, and 0.83 for chromatin fixed in methanol-acetic acid. When fixed chromatin was treated with saline-citrate at 60 degrees C for 3 hours, as used for G-banding chromosomes, the r value decreased from 0.83 to 0.55. When unfixed chromatin was treated as for R-banding the r values also dropped. Equilibrium dialysis indicated there was no disproportionate increase of dye binding as the concentration of DNA increased. -- These results, and others, suggest that some of the Giemsa negative regions of G- and R-banded chromosomes are due to the denaturation of non-histone proteins so that they more effectively cover the DNA and prevent side binding of the thiazin dyes.

📜 SIMILAR VOLUMES

Mechanisms of chromosome banding

✍ David E. Comings 📂 Article 📅 1975 🏛 Springer 🌐 English ⚖ 731 KB

The interaction of Hoechst 33258 with DNA has been examined to help clarify the mechanisms of banding. 1. In agreement with previous studies Hoechst fluorescence is enhanced to a greater degree in AT-rich compared to GC-rich DNA. 2. Hoechst causes an increase in the DNA Tm which is greater at the hi

Mechanisms of chromosome banding

✍ Tadashi A. Okada; David E. Comings 📂 Article 📅 1974 🏛 Springer 🌐 English ⚖ 933 KB

Mechanisms of chromosome banding

✍ David E. Comings; Maximo E. Drets 📂 Article 📅 1976 🏛 Springer 🌐 English ⚖ 779 KB

Prior studies on subfractions of mouse and Kangaroo rat DNA have suggested that variations in base concentration within a given genome may not be great enough to account for Q-banding. To examine this with another species, calf DNA was subfractionated by CsCl ultracentrifugation into GC-rich satelli

Mechanisms of Giemsa banding

✍ H. E. Wyandt; Ruth S. Anderson; S. R. Patil; F. Hecht 📂 Article 📅 1980 🏛 Springer 🌐 English ⚖ 416 KB

Molecular basis of chromosome banding

✍ K. Simola; R.-K. Selander; A. Chapelle; G. Corneo; E. Ginelli 📂 Article 📅 1975 🏛 Springer 🌐 English ⚖ 447 KB

The effects of mouse satellite, main band and total DNA on the fluorescence intensity of quinacrine and of the bibenzimidazole derivative Hoechst 33258 were tested in solution. No significant differences were noticed between the double-stranded DNAs in spite of the 5% difference in AT-content betwee

Molecular basis of chromosome banding

✍ K. Simola; R.-K. Selander; A. Chapelle 📂 Article 📅 1975 🏛 Springer 🌐 English ⚖ 325 KB

Silver and mercury ions are known to react with the bases of nucleic acids in solution. At low cation/base ratios Ag+ has an affinity for GC pairs in DNA, whereas Hg++ is preferentially bound to AT-rich nucleic acids. We have used fluorometry to measure the effect of these cations on the fluorescenc