ERCC6/CSB [D7]

DNA excision repair protein ERCC6, also known as Cockayne syndrome protein (CSB), is encoded by the ERCC6 gene in human. ERCC6 is the homolog of the yeast Rad26 protein. ERCC6 belongs in the SWI/SNF family of proteins as it contains helicase motifs and ATPase activity. It is a part of a complex that contains RNA pol I, TFIIH, and XPG, all of which are active in transcription and/or DNA repair. Hence, it is an essential factor involved in transcription-coupled nucleotide excision repair, which allows RNA polymerase II-blocking lesions to be rapidly removed from the transcribed strand of active genes. Upon DNA-binding, it locally modifies DNA conformation by wrapping the DNA around itself, thereby modifying the interface between stalled RNA polymerase II and DNA. It is shown to be essential for transcription-coupled repair complex formation. It recruits the CSA complex (ERCC8 complex), nucleotide excision repair proteins and EP300 to the sites of RNA polymerase II-blocking lesions. Mutations in CSB gene are known to cause age related macular degeneration and Cockayne syndrome B that is characterized by delayed neural development and severe progressive neurologic degeneration and mental retardation.