Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


ucin1083358247.pdf (924.62 KB)

ETD Abstract Container

Abstract Header

THE REGULATION OF THE CATECOLAMINERGIC PHENOTYPE IN PC12 CELLS BY HYPOXIA: THE RELATIONSHIP BETWEEN TYROSINE HYDROXYLASE, von HIPPEL-LINDAU TUMOR SUPPRESSOR PROTEIN AND HYPOXIA-INDUCIBLE FACTOR

BAUER, AMY LYNNE
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1083358247

Abstract Details

2004, PhD, University of Cincinnati, Medicine : Molecular and Cellular Physiology.
The cellular response to hypoxia involves changes in ion channel conductance, intracellular calcium ([Ca2+]i) fluxes, and activation of various signaling pathways, especially those involving the hypoxia inducible factor, HIF. HIF regulates the expression of various genes during hypoxia. In normoxia, the alpha-subunit of HIF is rapidly degraded via the ubiquitin-proteasome pathway. The von Hippel-Lindau protein (pVhl) mediates this degradation. Mutations and loss of heterozygosity of the VHL gene are linked to a familial cancer syndrome characterized by hemangioblastomas, renal cell carcinomas, and pheochromocytomas. Pheochromocytomas are tumors derived from chromaffin cells of the adrenal medulla that express increased amounts of tyrosine hydroxylase (TH), the rate limiting enzyme in catecholamine biosynthesis. The first aim of this study was to determine the role of endogenous pVhl in the regulation of TH gene expression, and the molecular mechanisms involved in this regulation. In PC12 cells expressing reduced endogenous pVhl due to the transfection of a VHL antisense RNA construct, levels of TH protein and mRNA were increased. Nuclear run-on analysis of the TH gene revealed enhanced efficiency of TH gene transcription during both normoxia and hypoxia in cells with decreased pVhl levels. This provides evidence that pVhl is a physiological regulator of the catecholaminergic phenotype. The second aim of this study was to characterize the role of the hypoxia-inducible transcription factors (HIFs) in TH gene expression. The hypoxic induction of TH gene expression was shown to involve HIFs, which interacted with a specific hypoxia-responsive element in the TH promoter. Levels of pVhl in part mediated the effects of HIFs on TH promoter activity. This indicates that HIFs play a role in regulating TH gene expression in oxygen-sensitive cells. The third aim was to determine the role Ca2+ plays in regulating HIF in PC12 cells. The hypoxic accumulation HIF-1 alpha protein is dependent on the presence of calcium in both PC12 and HepG2 cells. Calcium chelation did not affect the expression of HIF-1 alpha mRNA or protein degradation during hypoxia. The regulation of HIF-1 alpha by Ca2+ seemed to involve a PKC alpha pathway and regulation at the level of HIF-1 alpha protein translation.
Dr. Maria Czyzyk-Krzeska (Advisor)
121 p.
Biology, Molecular
Tyrosine Hydroxylase; von Hippel-Lindau protein; hypoxia-inducible factor; calcium; transcription elongation

Recommended Citations

Citations

  • BAUER, A. L. (2004). THE REGULATION OF THE CATECOLAMINERGIC PHENOTYPE IN PC12 CELLS BY HYPOXIA: THE RELATIONSHIP BETWEEN TYROSINE HYDROXYLASE, von HIPPEL-LINDAU TUMOR SUPPRESSOR PROTEIN AND HYPOXIA-INDUCIBLE FACTOR [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1083358247

    APA Style (7th edition)

  • BAUER, AMY. THE REGULATION OF THE CATECOLAMINERGIC PHENOTYPE IN PC12 CELLS BY HYPOXIA: THE RELATIONSHIP BETWEEN TYROSINE HYDROXYLASE, von HIPPEL-LINDAU TUMOR SUPPRESSOR PROTEIN AND HYPOXIA-INDUCIBLE FACTOR. 2004. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1083358247.

    MLA Style (8th edition)

  • BAUER, AMY. "THE REGULATION OF THE CATECOLAMINERGIC PHENOTYPE IN PC12 CELLS BY HYPOXIA: THE RELATIONSHIP BETWEEN TYROSINE HYDROXYLASE, von HIPPEL-LINDAU TUMOR SUPPRESSOR PROTEIN AND HYPOXIA-INDUCIBLE FACTOR." Doctoral dissertation, University of Cincinnati, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1083358247

    Chicago Manual of Style (17th edition)

ucin1083358247
748
© 2004, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.