DNA conformational transitions induced by supercoiling control transcription in chromatin.

Regulation of transcription in eukaryotes is considered in the light of recent findings demonstrating the presence of negative and positive superhelical tension in chromatin. This tension induces conformational transitions in DNA duplex. Particularly, the transition into A-form renders DNA accessible and waylaying for initiation of transcription producing RNA molecules long known to belong to the A-conformation.

A model of self-maintenance of in vivo malignant growth not dependent on tumour type or origin: syndrome of everlasting wound healing.

The common mechanism of permanent growth maintenance in all types of malignant tumours is proposed. According to the model, the main event, stimulating tumour growth is the stochastic but permanent death of a proportion of tumour cells as a result of inherent genetic instability of tumour cell genome (chromosome fragility). Dead cells trigger the complex and multicomponent process of wound healing, manifesting in stimulation of cell proliferation, angiogenesis, cell migration and other events.