Gloable gene expression is affected by loss of CSB function in the rat model for Cockayne syndrome

Cockayne syndrome (CS) is a rare genetic neurodevelopmental disorder, characterized by a deficiency in the transcription-coupled nucleotide excision repair pathway. Mutation of Cockayne syndrome B (CSB) affects basal transcription which is considered a major cause of CS neurological dysfunction. Here, we generated a rat model by mimicking a nonsense mutation in the CSB(ERCC6) gene of CS-B patients. CSB-deficient rats exhibit the well-known CS repair characteristics: inability to resume RNA synthesis from stalled RNA polymerase II (RNAP II) and persistent gamma H2AX overexpression after UV damage. In contrast to that of the Csb-/- mouse models, the cerebella of the CSB-deficient rats are more profoundly affected. Both the molecular and the granular layers of the cerebellum cortex showed significant atrophy. The white matter of the cerebellum demonstrated high GFAP staining indicative of reactive astrogliosis. RNA-seq analysis of CSB-deficient rat cerebella revealed that even in the absence of UV damage, CSB affects the expression of hundreds of genes, many of which are neuronal genes, suggesting that transcription dysregulation could contribute to the neurological features in CSB rat models.