NIPBL Controls RNA Biogenesis to Prevent Activation of the Stress Kinase PKR
CELL REPORTS
Authors: Yuen, Kobe C.; Xu, Baoshan; Krantz, Ian D.; Gerton, Jennifer L.
Abstract
NIPBL, a cohesin loader, has been implicated in transcriptional control and genome organization. Mutations in NIPBL, cohesin, and its deacetylase HDAC8 result in Cornelia de Lange syndrome. We report activation of the RNA-sensing kinase PKR in human lymphoblastoid cell lines carrying NIPBL or HDAC8 mutations, but not SMC1A or SMC3 mutations. PKR activation can be triggered by unmodified RNAs. Gene expression profiles in NIPBL-deficient lymphoblastoid cells and mouse embryonic stem cells reveal lower expression of genes involved in RNA processing and modification. NIPBL mutant lymphoblastoid cells show reduced proliferation and protein synthesis with increased apoptosis, all of which are partially reversed by a PKR inhibitor. Non-coding RNAs from an NIPBL mutant line had less m(6) A modification and activated PKR activity in vitro. This study provides insight into the molecular pathology of Cornelia de Lange syndrome by establishing a relationship between NIPBL and HDAC8 mutations and PKR activation.
Genetic and clinical variations in a Norwegian sample diagnosed with Rett syndrome
BRAIN & DEVELOPMENT
Authors: Henriksen, Mari Wold; Breck, Hilde; Sejersted, Yngve; Diseth, Trond; von Tetzchner, Stephen; Paus, Benedicte; Skjeldal, Ola H.
Abstract
Background and purpose: Rett syndrome (RTT) is a neurodevelopmental disorder mainly caused by mutations in MECP2. The diagnostic criteria of RTT are clinical; mutations in MECP2 are neither diagnostic nor necessary, and a mutation in another gene does not exclude RTT. We attempted to correlate genotype and phenotype to see if there are significant clinical associations. Methods: All available females diagnosed with RTT in Norway were invited to the study. Parents were interviewed, the girl or woman with RTT examined and medical records reviewed. All diagnoses were revisited according to the current diagnostic criteria and exome-based sequencing analyses were performed in individuals without an identified causative mutation. Participants were categorized according to genotypes and RTT diagnosis. Individuals with RTT with and without mutations in MECP2 were compared. Results: Ninety-one individuals were included. A presumed causative mutation was identified in 86 individuals, of these, mutations in MECP2 in 77 individuals and mutations in SMC1A, SYNGAP1, SCN1A, CDKL5, FOXG1 or chromosome 13q in nine. Seventy-two individuals fulfilled the diagnostic criteria for classic and 12 for atypical RTT. Significant differences in early development, loss of hand use and language, intense eye gaze and the presence of early onset epilepsy were revealed in individuals with RTT according to their MECP2 genotypic status. Conclusion: Using the current diagnostic criteria, genetic and clinical variation in RTT is considerable. Significant differences between individuals with RTT with and without MECP2 mutations indicate that MECP2 is a major determinant for the clinical phenotype in individuals with RTT. (C) 2020 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.