title: Functional Implications of the CLOCK 3111T/C Single-Nucleotide Polymorphism.
abstract: Circadian rhythm disruptions are prominently associated with bipolar disorder (BD). Circadian rhythms are regulated by the molecular clock, a family of proteins that function together in a transcriptional-translational feedback loop. The CLOCK protein is a key transcription factor of this feedback loop, and previous studies have found that manipulations of the Clock gene are sufficient to produce manic-like behavior in mice (1). The CLOCK 3111T/C single-nucleotide polymorphism (SNP; rs1801260) is a genetic variation of the human CLOCK gene that is significantly associated with increased frequency of manic episodes in BD patients (2). The 3111T/C SNP is located in the 3'-untranslated region of the CLOCK gene. In this study, we sought to examine the functional implications of the human CLOCK 3111T/C SNP by transfecting a mammalian cell line (mouse embryonic fibroblasts isolated from Clock(-/-) knockout mice) with pcDNA plasmids containing the human CLOCK gene with either the T or C SNP at position 3111. We then measured circadian gene expression over a 24-h time period. We found that the CLOCK3111C SNP resulted in higher mRNA levels than the CLOCK 3111T SNP. Furthermore, we found that Per2, a transcriptional target of CLOCK, was also more highly expressed with CLOCK 3111C expression, indicating that the 3'-UTR SNP affects the expression, function, and stability of CLOCK mRNA.
authors.affiliation: Department of Psychiatry and Translational Neuroscience Program, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA; Portland Alcohol Research Center, VA Medical Center, Portland, OR, USA.
authors.forename: Angela R
authors.initials: AR
authors.lastname: Ozburn
authors.affiliation: Department of Psychiatry and Translational Neuroscience Program, University of Pittsburgh School of Medicine , Pittsburgh, PA , USA.
authors.forename: Kush
authors.initials: K
authors.lastname: Purohit
authors.affiliation: Department of Psychiatry and Translational Neuroscience Program, University of Pittsburgh School of Medicine , Pittsburgh, PA , USA.
authors.forename: Puja K
authors.initials: PK
authors.lastname: Parekh
authors.affiliation: Department of Psychiatry and Translational Neuroscience Program, University of Pittsburgh School of Medicine , Pittsburgh, PA , USA.
authors.forename: Gabrielle N
authors.initials: GN
authors.lastname: Kaplan
authors.affiliation: Department of Pharmacology, University of Pennsylvania , Philadelphia, PA , USA.
authors.forename: Edgardo
authors.initials: E
authors.lastname: Falcon
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center , Dallas, TX , USA.
authors.forename: Shibani
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA; Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Hannah M
authors.initials: HM
authors.lastname: Cates
authors.affiliation: Department of Psychiatry and Translational Neuroscience Program, University of Pittsburgh School of Medicine , Pittsburgh, PA , USA.
authors.forename: Colleen A
authors.initials: CA
authors.lastname: McClung
keywords: bipolar disorder; cell culture; circadian; clock; gene expression; single-nucleotide polymorphism