Expression and regulation of rat 6-pyruvoyl tetrahydropterin synthase mRNA.
6-Pyruvoyl tetrahydropterin synthase catalyzes the second step in the biosynthesis of tetrahydrobiopterin. In the present study, the reverse transcription-polymerase chain reaction technique was used to clone a portion of 6-pyruvoyl tetrahydropterin synthase cDNA from rat pineal gland RNA. The sequence of this cDNA was found to be essentially identical to that previously reported for the rat liver. 6-Pyruvoyl tetrahydropterin synthase mRNA levels in various rat tissues, including the brain, were then analyzed by Northern blot and nuclease protection assay. A single 1.35 kb transcript of 6-pyruvoyl tetrahydropterin synthase mRNA was detected by Northern blot analysis in the rat adrenal gland, brain-stem, and liver. Quantitation by nuclease protection assay demonstrated that 6-pyruvoyl tetrahydropterin synthase mRNA was most abundant in the adrenal gland, kidney, and pineal gland (19.5-25.5 amol/microgram RNA). Relatively homogeneous levels of 6-pyruvoyl tetrahydropterin synthase mRNA were found in various brain regions including the cerebellum, substantia nigra and locus coeruleus (4.12-12 amol/microgram RNA). In the adrenal gland, 6-pyruvoyl tetrahydropterin synthase and tyrosine hydroxylase mRNAs were elevated between 3 and 4-fold 24 h after a single dose of reserpine (10 mg/kg), a treatment known to increase tetrahydrobiopterin levels in this tissue. This result suggests that although 6-pyruvoyl tetrahydropterin synthase is not believed to be rate-limiting in the tetrahydrobiopterin biosynthetic pathway, control of gene expression for this enzyme may play an essential role in regulating the synthesis of this important cofactor.
Hirayama
K
K
Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI 48201, USA.
Kapatos
G
G
D015720:5'-Nucleotidase / Q000378:metabolism; D000429:Alcohol Oxidoreductases / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D001345:Autoradiography; D001483:Base Sequence; D015152:Blotting, Northern; D018076:DNA, Complementary / Q000096:biosynthesis; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D008297:Male; D008969:Molecular Sequence Data; D019761:Phosphorus-Oxygen Lyases; D010870:Pineal Gland / Q000187:drug effects / Q000201:enzymology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D012194:RNA-Directed DNA Polymerase; D051381:Rats; D017207:Rats, Sprague-Dawley; D012110:Reserpine / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D018076:DNA, Complementary; D012333:RNA, Messenger; D012110:Reserpine; D000429:Alcohol Oxidoreductases; D014446:Tyrosine 3-Monooxygenase; D012194:RNA-Directed DNA Polymerase; D015720:5'-Nucleotidase; D019761:Phosphorus-Oxygen Lyases; C043497:6-pyruvoyltetrahydropterin synthase