Bifractal structure of chromatin in rat lymphocyte nuclei

The small-angle neutron scattering (SANS) on the rat lymphocyte nuclei demonstrates the bifractal nature of the chromatin structural organization. The scattering intensity from rat lymphocyte nuclei is described by power law Q(-D) with fractal dimension approximately 2.3 on smaller scales and 3 on larger scales. The crossover between two fractal structures is detected at momentum transfer near 10(-1) nm(-1). The use of contrast variation (D2O-H2O) in SANS measurements reveals clear similarity in the structural organizations of nucleic acids (NA) and proteins. Both chromatin components show bifractal behavior with logarithmic fractal structure on the large scale and volume fractal with slightly smaller than 2.5 structure on the small scale. Scattering intensities from chromatin, protein component, and NA component demonstrate an extremely extensive range of logarithmic fractal behavior (from 10(-3) to approximately 10(-1) nm(-1)). We compare the fractal arrangement of rat lymphocyte nuclei with that of chicken erythrocytes and the immortal HeLa cell line. We conclude that the bifractal nature of the chromatin arrangement is inherent in the nuclei of all these cells. The details of the fractal arrangement-its range and correlation/interaction between nuclear acids and proteins are specific for different cells and is related to their functionality.

Automated summary

The study on rat lymphocyte nuclei using small-angle neutron scattering (SANS) revealed the bifractal nature of chromatin structural organization with different fractal dimensions on varying scales. The contrast variation in SANS measurements showed similarity in the structural organizations of nucleic acids (NA) and proteins, both exhibiting bifractal behavior. The details of fractal arrangement and interaction between nuclear acids and proteins were found to be specific to different cells and related to their functionality.