Conformational constraints in nuclear DNA.
نویسندگان
چکیده
We have investigated DNA superstructure in a wide range of nuclei of higher cells by gently lysing cells to release structures that resemble nuclei but are depleted of nuclear proteins. The sedimentation properties of these structures, which we call nucleoids, have been examined in sucrose gradients containing the intercalating agent, ethidium. The sedimentation rate of nucleoids derived from the growing cells of mammals, birds, amphibians and insects varies in the manner characteristic of circular and superhelical molecules of DNA. These characteristic changes in sedimentation rate are abolished by irradiating the nucleoids with low doses of gamma-rays, a procedure known to introduce single-strand scissions into DNA. We have also investigated by similar means DNA superstructure in nucleoids derived from a variety of different chick cells. Nucleoids derived from adult hen erythrocytes differ from the other nucleoids studied in that their sedimentation rate does not vary in the manner characteristic of supercoiled DNA.
منابع مشابه
Knowledge-Based versus experimentally Acquired Distance and Angle Constraints for NMR Structure Refinement
Nuclear Overhauser effects (NOE) distance constraints and torsion angle constraints are major conformational constraints for nuclear magnetic resonance (NMR) structure refinement. In particular, the number of NOE constraints has been considered as an important determinant for the quality of NMR structures. Of course, the availability of torsion angle constraints is also critical for the formati...
متن کاملInsights into the Human Glycan Receptor Conformation of 1918 Pandemic Hemagglutinin–Glycan Complexes Derived from Nuclear Magnetic Resonance and Molecular Dynamics Studies
The glycan receptor binding and specificity of influenza A viral hemagglutinin (HA) are critical for virus infection and transmission in humans. However, ambiguities in the interpretation of the receptor binding specificity of hemagglutinin from human- and avian-adapted viruses have prevented an understanding of its relationship with aerosol transmissibility, an exclusive property of human-adap...
متن کاملRegulation of chromatin binding by a conformational switch in the tail of the Ran exchange factor RCC1
RCC1 is the only known exchange factor for the Ran guanosine triphosphatase and performs essential roles in nuclear transport, spindle organization, and nuclear envelope formation. RCC1 binds to chromatin through a bimodal attachment to DNA and histones, and defects in binding cause chromosome missegregation. Chromatin binding is enhanced by apo-Ran. However, the mechanism underlying this regul...
متن کاملP-37: Effect of Gibberellic Acid on Sperm DNA Double Strand Integrity, Nuclear Maturity and Motility
Background: Plant growth regulators gave entry into animals and human cells through diet. Gibberellic acid (GA3) is an extensively prevalent plant growth regulator due to its use in agriculture. Therefore current study was designed to investigate the effect of GA3 compound on sperm DNA integrity, nuclear maturity and motility. Materials and Methods: To follow-up current study 12 mature male s r...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of cell science
دوره 22 2 شماره
صفحات -
تاریخ انتشار 1976