EXPRESSION AND POST-TRANSLATIONAL MODIFICATION OF HUMAN 4-HYDROXY-PHENYLPYRUVATE DIOXYGENASE

Authors

  • Lene Aarenstrup,

    1. Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
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  • Anne-Marie Falch,

    1. Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
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  • Kirsten K. Jakobsen,

    1. Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
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  • Søren Neve,

    1. Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
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  • Linda Ø Henriksen,

    1. Institute of Human Genetics, Aarhus University, Wilhelm Meyers Allé, DK-8000, Aarhus, Denmark
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  • Niels Tommerup,

    1. Department of Medical Genetic, Building 24, Panum Institute, Blegdamsvej 3b, University of Copenhagen, DK-2200, Copenhagen N, Denmark
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  • Henrik Leffers,

    1. Department of Growth and Reproduction, Section GR-5064, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen Ø Denmark
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  • Karsten Kristiansen

    Corresponding author
    1. Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
      To whom correspondence should be addressed: Dr Karsten Kristiansen, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5320 Odense M, Denmark. Tel.: (+45) 6550 2408; Fax: (+45) 6550 2467; E-mail: kak@bmb.sdu.dk
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To whom correspondence should be addressed: Dr Karsten Kristiansen, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5320 Odense M, Denmark. Tel.: (+45) 6550 2408; Fax: (+45) 6550 2467; E-mail: kak@bmb.sdu.dk

Abstract

4-hydroxyphenylpyruvate dioxygenase (HPD) (EC 1.13.11.27) is a key enzyme involved in tyrosine catabolism. Congenital HPD deficiency is a rare, relatively benign condition known as hereditary type III tyrosinemia. The severe type I tyrosinemia, caused by a deficiency of fumarylacetoacetate hydrolase which functions downstream of HPD in the tyrosine degradation pathway, is often associated with decreased expression of HPD, and interestingly, inhibition of HPD activity seems to ameliorate the clinical symptoms of type I tyrosinemia. The HPD gene was previously mapped to the chromosomal region 12q24→5;qter. In the present study high-resolution chromosome mapping localized the HPD gene to 12q24.31. DNase I footprinting, revealed that four regions of the HPD promoter were protected by rat liver nuclear proteins. Computer-assisted analyses suggested that these elements might bind Sp1/AP2, HNF4, HNF3/CREB, and C/EBP, respectively. In transient transfection experiments, the proximal 271bp of the promoter conferred basal transcriptional activation in human Chang cells. Sequences in intron 1 were able to enhance the activity of this basal promoter. Finally, vaccinia virus-based expression provided evidence that HPD is subject to phosphorylation, and furthermore, allowed mapping of the HPD protein in the human keratinocyte 2D database.

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