Jamming the transcription machinery

Abstract

Nucleotide excision repair (NER) removes bulky DNA adducts from the genome, but, when an elongating RNA polymerase II (RNA polII) complex is stalled by DNA damage, a special task force is required. In a process called transcription-coupled nucleotide excision repair (TC-NER), two gene products, CSA and CSB, are thought to be involved in clearing the RNA polII complex, allowing access for the NER machinery. A defect in either protein causes Cockayne syndrome (CS), a disease that shows some striking symptoms of premature aging. Because completely NER-defective xeroderma pigmentosum (XP) patients lack these symptoms, a transcriptional rather than a DNA repair defect might underlie CS.