Project description:Prader-Willi syndrome (PWS), a genetic cause of childhood obesity, is characterized by intellectual disabilities and sleep abnormalities. PWS-causing deletions include a neuronal long, non-coding RNA (lncRNA) processed into small nucleolar RNAs and a spliced lncRNA,116HG. We show that 116HG forms a subnuclear RNA cloud that co-purifies with the transcriptional activator RBBP5 and active metabolic genes, remains tethered to the site of its transcription and increases in size in postnatal neurons. Snord116del mice lacking 116HG exhibited increased energy expenditure corresponding to dysregulation of diurnally expressed Mtor and circadian genes Clock, Cry1, and Per2. Genomic and metabolic analyses demonstrate altered diurnal energy regulation in the Snord116del mouse cortex and link the loss of 116HG to the energy imbalance observed in PWS.
Project description:Prader-Willi syndrome (PWS), a genetic cause of childhood obesity, is characterized by intellectual disabilities and sleep abnormalities. PWS-causing deletions include a neuronal long, non-coding RNA (lncRNA) processed into small nucleolar RNAs and a spliced lncRNA,116HG. We show that 116HG forms a subnuclear RNA cloud that co-purifies with the transcriptional activator RBBP5 and active metabolic genes, remains tethered to the site of its transcription and increases in size in postnatal neurons. Snord116del mice lacking 116HG exhibited increased energy expenditure corresponding to dysregulation of diurnally expressed Mtor and circadian genes Clock, Cry1, and Per2. Genomic and metabolic analyses demonstrate altered diurnal energy regulation in the Snord116del mouse cortex and link the loss of 116HG to the energy imbalance observed in PWS. Examination of lncRNA binding sites by ChIRP-seq using an oligo-based purification method from WT and Snord116del (+/-) mouse brain with specific and nonspecific control oligos. Transcript abundance levels by RNA-seq analysis of 3 adult WT and 2 adult Snord116del (+/-) mouse brain cortices at Zt+6 and 2 adult WT and 2 adult Snord116del (+/-) mouse brain cortices at Zt+16.
Project description:Parental imprinting is a form of epigenetic regulation that results in parent-of-origin differential gene expression. To study Prader-Willi syndrome (PWS), a developmental imprinting disorder, we generated patient-derived induced pluripotent stem cells (iPSCs) harboring distinct deletions in the affected region on chromosome 15. Studying PWS-iPSCs and human parthenogenetic iPSCs unexpectedly revealed substantial upregulation of virtually all maternally expressed genes (MEGs) in the imprinted DLK1-DIO3 locus on chromosome 14. Subsequently, we identified IPW, a long noncoding RNA in the critical region of the PWS locus, as a regulator of the DLK1-DIO3 region, as its over-expression in PWS and parthenogenetic iPSCs results in downregulation of the MEGs in this locus. We further show that gene expression changes in the DLK1-DIO3 region coincide with chromatin modifications, rather than DNA methylation levels. Our results suggest that a subset of PWS phenotypes may arise from dysregulation of an imprinted locus distinct from the PWS region. Gene expression analysis was performed on a total of 4 human cell lines, including 3 Prader-Willi Syndrome indcued pluripotent stem cell lines - derived from 3 affected individuals and one of their parental fibroblast cell line.
Project description:Rhythmic oscillations of physiological processes depend on integrating the circadian clock and diurnal environment. DNA methylation is epigenetically responsive to daily rhythms, as a subset of CpG dinucleotides in brain exhibit diurnal rhythmic methylation. A major genetic effect on rhythmic methylation was identified in a mouse Snord116 deletion model of the imprinted disorder Prader-Willi syndrome (PWS). > 23,000 diurnally rhythmic CpGs were identified in wild-type cortex, with nearly all lost or phase-shifted in PWS. Circadian dysregulation of a second imprinted Snord cluster at the Temple/Kagami-Ogata syndrome locus was observed at the level of methylation, transcription, and chromatin, providing mechanistic evidence of cross-talk. Genes identified by diurnal epigenetic changes in PWS mice overlapped rhythmic and PWS-specific genes in human brain and were enriched for PWS-relevant phenotypes and pathways. These results support the proposed evolutionary relationship between imprinting and sleep, and suggest possible chronotherapy in the treatment of PWS and related disorders.
Project description:Prader-Willi syndrome (PWS) is a genetic disorder caused by deficiency of imprinted gene expression from the paternal chromosome 15q11-15q13 and clinically characterized by neonatal hypotonia, short stature, cognitive impairment, hypogonadism, hyperphagia, morbid obesity and diabetes. Previous clinical studies suggest that a defect in energy metabolism may be involved in the pathogenesis of PWS. Assessment of enzyme activities of mitochondrial oxidative phosphorylation (OXPHOS) complexes in the brain, heart, liver and muscle were assessed. We used microarrays to detail the global programme of gene expression underlyingthe PWS and identified distinct classes of disregulated genes during this process. Skeletal (quadriceps) muscle Vastus Lateralis and whole brain samples from the mutant mice and their wild-type age-matched littermates were analyzed by microarray technology using the Mouse Genome 430 2.0 arrays (Affymetrix).
Project description:Prader-Willi syndrome (PWS) is a genetic disorder caused by deficiency of imprinted gene expression from the paternal chromosome 15q11-15q13 and clinically characterized by neonatal hypotonia, short stature, cognitive impairment, hypogonadism, hyperphagia, morbid obesity and diabetes. Previous clinical studies suggest that a defect in energy metabolism may be involved in the pathogenesis of PWS. Assessment of enzyme activities of mitochondrial oxidative phosphorylation (OXPHOS) complexes in the brain, heart, liver and muscle were assessed. We used microarrays to detail the global programme of gene expression underlyingthe PWS and identified distinct classes of disregulated genes during this process.
Project description:Mice with a congenital Snord116 deletion model aspects of the Prader-Willi Syndrome. In this study, we examine the gene expression changes in four hypothalamic nuclei across 24-hour food deprived versus ad libitum fed mice.
Project description:The dysregulation of genes in neurodevelopmental disorders that lead to social and cognitive phenotypes is a complex, multilayered process involving both genetics and epigenetics. Parent-of-origin effects of deletion and duplication of the 15q11-q13 locus leading to Angelman, Prader-Willi, and Dup15q syndromes are due to imprinted genes, including UBE3A, which is maternally expressed exclusively in neurons. UBE3A encodes a ubiquitin E3 ligase protein with multiple downstream targets, including RING1B, which in turn monoubiquitinates histone variant H2A.Z. To understand the impact of neuronal UBE3A levels on epigenome-wide marks of DNA methylation, histone variant H2A.Z positioning, active H3K4me3 promoter marks, and gene expression, we took a multi-layered genomics approach. We performed an siRNA knockdown of UBE3A in two human neuroblastoma cell lines, including parental SH-SY5Y and the SH(15M) model of Dup15q. Genes differentially methylated across cells with differing UBE3A levels were enriched for functions in gene regulation, DNA binding, and brain morphology. Importantly, we found that altering UBE3A levels had a profound epigenetic effect on the methylation levels of up to half of known imprinted genes. Genes with differential H2A.Z peaks in SH(15M) compared to SH-SY5Y were enriched for ubiquitin and protease functions and associated with autism, hypoactivity, and energy expenditure. Together, these results support a genome-wide epigenetic consequence of altered UBE3A levels in neurons and suggest that UBE3A regulates an imprinted gene network involving DNA methylation patterning and H2A.Z deposition.