Nuclear structure and higher order gene structure: their role in the control of chemically-induced neoplastic...

An overview is hereby given of the physical and physicochemical alterations at the level of nuclear structures in rat liver cells, following a chemically-induced neoplastic transformation. These alterations refer to chromatin-DNA structure, from secondary (B- versus A- and Z-form) to tertiary-quanternary up to quinternary (in situ), and to the physical state of water. Possible molecular mechanisms-linking global chromatin changes to single gene expression in the control of neoplastic transformation-are discussed in terms of the degree of negative superhelicity of fibrosomes, recently identified single repeating structural subunits and hereby associated with single functional genes.