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dc.contributor.authorChen, Frances
dc.date.accessioned2018-10-23T13:35:10Z
dc.date.available2020-08-22T06:00:22Z
dc.date.issued2018-08-30
dc.identifier.otherChen_cornellgrad_0058F_11110
dc.identifier.otherhttp://dissertations.umi.com/cornellgrad:11110
dc.identifier.otherbibid: 10489806
dc.identifier.urihttps://hdl.handle.net/1813/59710
dc.description.abstractThe genome contains the code of life: conservation of DNA sequence ensures proper stereotypical patterning and precise formation of the body’s tissues replicated in members of the same species, while variation in DNA sequence contributes to unique individual and species’ differences in physical form, function, and susceptibility to disease. Genome wide association studies (GWAS) have shown that most sequence variation linked to disease is located not in protein coding genes but in noncoding sequence. The noncoding genome is known to play important roles in regulating chromatin structure and gene expression, and understanding its function will translate to improved understanding of genetic disease and health outcomes. In this dissertation, I have used CRISPR/Cas9 genome editing to perturb noncoding regulatory elements at the critical developmental Pitx2 locus to investigate their function in organogenesis and human disease. The transcription factor Pitx2 patterns the left-right (LR) embryonic axis and regulates LR asymmetric organogenesis. Loss of left-specific Pitx2 expression is linked to life threatening congenital defects of the heart and intestines. Importantly, mutations affecting noncoding sequence upstream of Pitx2 while leaving the Pitx2 gene intact are associated with Pitx2-mediated disease, suggesting that cis-regulatory elements may regulate Pitx2 expression. Here we have investigated differences in chromatin structure and transcription underlying LR asymmetric organogenesis at the Pitx2 locus. We use transcriptional profiling to identify a novel conserved long noncoding RNA, Playrr, that is expressed asymmetric and complementary to Pitx2 and participates in mutually antagonistic transcriptional regulation with Pitx2. In addition to its essential roles in LR organ development, Pitx2 and its genomic locus have been linked to atrial fibrillation (AF), the most common arrhythmia worldwide in humans. Despite multiple GWAS identifying noncoding variants at the Pitx2 locus in association with the most significant genetic contribution to AF risk, the function of these variants and mechanisms by which they may mediate cis-regulation of Pitx2 and AF pathophysiology remain unknown. Here, using CRISPR/Cas9 genome editing in mice to target the Playrr RNA transcript, I demonstrate that Playrr mutant mice have evidence of pacemaker dysfunction and are predisposed to AF, mirroring arrhythmia phenotypes found in Pitx2 loss-of-function mutants and Pitx2 heterozygous mice, suggesting a relationship between Playrr, Pitx2, and AF. In conclusion, my work uncovers a role for the lncRNA Playrr in arrhythmia and provides multiple novel noncoding mouse models to investigate functions of the cis-regulatory genome and the chromatin level mechanisms in the context of Pitx2-related disease.
dc.language.isoen_US
dc.rightsAttribution-NoDerivatives 4.0 International*
dc.rights.urihttps://creativecommons.org/licenses/by-nd/4.0/*
dc.subjectLR asymmetry
dc.subjectPitx2
dc.subjecttranscriptional regulation
dc.subjectDevelopmental biology
dc.subjectGenetics
dc.subjectatrial fibrillation
dc.subjectintestinal morphogenesis
dc.subjectlncRNA
dc.titleGENOMIC REGULATORY ELEMENTS IN TRANSCRIPTION, DEVELOPMENT, AND DISEASE: GENERATING MOUSE MODELS FOR LATERALITY DEFECTS USING CRISPR/CAS9 GENOME ENGINEERING AT THE PITX2 LOCUS
dc.typedissertation or thesis
thesis.degree.disciplineComparative Biomedical Sciences
thesis.degree.grantorCornell University
thesis.degree.levelDoctor of Philosophy
thesis.degree.namePh. D., Comparative Biomedical Sciences
dc.contributor.chairKurpios, Natasza
dc.contributor.committeeMemberSoloway, Paul
dc.contributor.committeeMemberSchimenti, John C.
dc.contributor.committeeMemberFortier, Lisa Ann
dcterms.licensehttps://hdl.handle.net/1813/59810
dc.identifier.doihttps://doi.org/10.7298/X42Z13QK


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