Changes in chromatin structure during rat liver regeneration as demonstrated by thermal melting analyses.

Chromatin was isolated from regenerating rat livers at different times after 2/3 hepatectomy and enriched with respect to active sequences. Thermal melting analyses of the material resulted in profiles reflecting the specific structural organization of the chromatin during different phases of the regeneration process: The high transcriptional activity of the chromatin 1, 16, and 36 hours after hepatectomy is demonstrated by a high proportion of DNA-protein complexes melting between 80 degrees C and 85 degrees C, while the period of active DNA synthesis 24 hours after hepatectomy is reflected by high amounts of components with Tm around 90 degrees C.

Early alterations in rat liver chromatin structure after a single dose of diethylnitrosamine.

In the chromatin of 24-h regenerating rat livers, derivative melting profiles are characterized by a high proportion of transitions above 90 degrees C. After the injection of diethylnitrosamine there is a rapid shift to lower melting temperatures. This is due to a rearrangement of the chromatin to higher amounts of nucleosomal components but possibly also a consequence of chemical modifications and conformational alterations of the DNA.