Cockayne syndrome B protein: connection between repair, transcription and chromatin structure

DNA is the carrier of the genetic instructions in all living organisms. Its integrity is of vital importance for a faithful transmission of the genetic information and for the proper fimctioning of cellular processes. However, the DNA molecule is susceptible to alterations caused by both intrinsic chemical instability (e.g. deatninatioll, depurinatioll etc.) and by a wide variety of environmental and endogenous compounds. The most prominent DNAwdamaging physical agents arc ultraviolet (UV) light and ionizing radiation (X-rays and y-rays). DNA damage can disturb cellular processes and can have severe consequences on human health. Its direct effect at the cellular level is inhibition of vital processes, most notably transcription, replication and cell cycle progression. Accumulation of lesions in DNA can either lead to cell death by apoptosis or to permanent mutations in the genetic code which can cause inborn diseases and contribute to premature aging. Importantly, mutations in proto-oncogenes and tumor suppressor genes are involved in the initial stages and subsequential progression of the multi-step process of carcinogenesis.