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The Transcriptome of the Suprachiasmatic Nucleus and its Response to Photic Stimuli

Porterfield, Veronica Marie
http://rave.ohiolink.edu/etdc/view?acc_num=kent1228167654

Abstract Details

2008, PHD, Kent State University, College of Arts and Sciences / School of Biomedical Sciences.
Circadian rhythms in mammals are driven by a clock located in the suprachiasmatic nucleus of the hypothalamus (SCN). The transmission of information about the photic environment to the circadian clock involves a complex array of neurotransmitters, receptors, and second messenger systems. Light pulses given during early subjective night cause phase delays of circadian rhythms of behavior in mice and hamsters. Identification of novel light induced genes in the SCN of hamsters and mice was done using a combination of laser capture microscopy and expression microarray analysis. While the hamsters yielded no novel genes, a total of 12 genes were identified in mice as significantly upregulated, with 4 novel light induced genes, Egr2, Pim3, Gadd45b, and Tiparp. Next, comparative genomic analysis was performed to ask whether all of the light-inducible genes in the SCN contained conserved CRE elements in their promoters. The genes identified as being light-induced share the common feature of CRE elements within their promoter regions that are conserved across multiple mammalian orders. The time course of light-induced genes was examined to determine whether all genes followed the same expression pattern. Three patterns of mRNA expression were observed; (1) high induction at the first time point and decrease to baseline levels by the last time point, as exemplified by Fos, (2) low induction of mRNA at the first time point, followed by an increase in expression up to the last time point as seen in Per2, and (3) quick induction of expression at the first time point that remains elevated throughout the course of the study, as seen in Rrad. Due to the high light-induced expression level of Rrad two hours after the end of photic stimulation, an attempt to localize Rrad was made using in situ hybridization and the mRNA was sequenced. A meta-analysis comparing previously published microarray studies in the SCN of mice and rats was performed to compare neurotransmitter and neuropeptide systems in the SCN. Taken together, these data expand our current knowledge of the transcriptome of the SCN and its response to photic stimulation.
Eric Mintz, PhD (Committee Chair)
155 p.
Biology; Biomedical Research; Cellular Biology; Molecular Biology
circadian; suprachiasmatic; microarray; laser capture; light-induced genes

Recommended Citations

Citations

  • Porterfield, V. M. (2008). The Transcriptome of the Suprachiasmatic Nucleus and its Response to Photic Stimuli [Doctoral dissertation, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1228167654

    APA Style (7th edition)

  • Porterfield, Veronica. The Transcriptome of the Suprachiasmatic Nucleus and its Response to Photic Stimuli. 2008. Kent State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1228167654.

    MLA Style (8th edition)

  • Porterfield, Veronica. "The Transcriptome of the Suprachiasmatic Nucleus and its Response to Photic Stimuli." Doctoral dissertation, Kent State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=kent1228167654

    Chicago Manual of Style (17th edition)

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© 2008, all rights reserved.
This open access ETD is published by Kent State University and OhioLINK.