Project description:To investigate the changes in circRNAs expression after SVA infection in PK-15 cells, we established a model of SVA-infected PK-15 cells.
Project description:X-linked dystonia parkinsonism (XDP) is an inherited neurodegenerative disease characterized by the antisense insertion of an SVA retrotransposon into the TAF1 gene, encoding for the largest subunit of the basal transcription factor TFIID, which is essential for RNA polymerase II activity. This SVA insertion has been associated with altered TAF1 expression levels, but the cause of this outcome and its link to the development of XDP remain unknown. Unique to the XDP SVA compared to other SVA retrotransposons in the human genome is the amplification of the (GGGAGA)n repeat domain, creating a unique G4-prone region, whose length correlates with age at onset and disease severity. By ChIP-seq and ChIP-qPCR with the anti-G4 antibody BG4, we assessed that G4s are present in the folded state in the XDP SVA of these cells. Using available G4 ligands, we demonstrated that stabilization of the XDP SVA G4s reduces TAF1 transcripts in the exons around and downstream of the SVA, while increasing the transcription of the upstream exons, possibly through a positive feedback loop.
Project description:SVA retrotransposons remain active in humans and contribute to individual genetic variation. Polymorphic SVA alleles harbor gene-regulatory potential and can cause genetic disease. However, how SVA insertions are controlled and functionally impact human disease is unknown. Here, we dissect the epigenetic regulation and influence of SVAs in cellular models of X-linked dystonia-parkinsonism (XDP), a neurodegenerative disorder caused by an SVA insertion at the TAF1 locus. We demonstrate that the KRAB zinc finger protein ZNF91 establishes H3K9me3 and DNA methylation over SVAs, including polymorphic alleles, in human neural progenitor cells. The resulting mini-heterochromatin domains attenuate the cis-regulatory impact of SVAs. This is critical for XDP pathology; removal of local heterochromatin severely aggravates the XDP molecular phenotype, resulting in increased TAF1 intron retention and reduced expression. Our results provide unique mechanistic insights into how human polymorphic transposon insertions are recognized, and their regulatory impact constrained by an innate epigenetic defense system.
Project description:We have performed microarray hybridization studies on forty clinical isolates from twelve common serovars within Salmonella enterica subspecies I (sspI) to identify the conserved gene pool present.
Project description:The Genotype-Tissue Expression (GTEx) project is a collaborative effort that aims to identify correlations between genotype and tissue-specific gene expression levels that will help identify regions of the genome that influence whether and how much a gene is expressed. GTEx is funded through the Common Fund, and managed by the NIH Office of the Director in partnership with the National Human Genome Research Institute, National Institute of Mental Health, the National Cancer Institute, the National Center for Biotechnology Information at the National Library of Medicine, the National Heart, Lung and Blood Institute, the National Institute on Drug Abuse, and the National Institute of Neurological Diseases and Stroke, all part of NIH. This series of 837 samples represents multiple tissues collected from 102 GTEX donors and 1 control cell line. In total, 30 tissue sites are represented including Adipose, Artery, Heart, Lung, Whole Blood, Muscle, Skin, and 11 brain subregions. RNA-seq expression data, robust clinical data, pathological annotations, and genotypes are also available for these samples from dbGaP (http://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?study_id=phs000424.v2.p1) and the GTEx portal (www.broadinstitute.org/gtex). While GTEx is no longer generating Affymetrix expression data, donor enrollment continues and is expected to reach 1,000 by the end of 2015. Updates to the GTEx data in dbGaP and the GTEx Portal will be made periodically. contributor: GTEx Laboratory, Data Analysis, and Coordinating Center (LDACC) contributor: The Broad Institute of MIT and Harvard (LDACC PIs: Kristin Ardlie and Gaddy Getz)