ZANGER Ulrich M. Universitat Basel, Biozentrum, Research Associate, バイオセンター, 研究員
WALTER Peter University of California San Francisco, Medical School, Professor, 医学部, 教授
VON HEIJNE Gunnar Karolinska Institute, Department of Molecular Biology, Associate Prof., 準教授
PARKER Keith L. Duke University, Medical Center, Professor, 医学部, 教授
WATERMAN Mic バンデルビルト大学, 医学部, 教授
SAKAGUCHI Masao Kyushu University, Graduate School of Medical Science, Instructor, 大学院医学系研究科, 助手 (30205736)
MOROHASHI Ken-ichirou Kyushu University, Graduate School of Medical Science, Instructor, 大学院医学系研究科, 助手 (30183114)
ITO Akio Kyushu University, Faculty of Science, Professor, 理学部, 教授 (30037379)
MIHARA Katsuyoshi Kyushu University, Graduate School of Medical Science, Associate Professor, 大学院医学系研究科, 助教授 (40029963)
WATERMAN Michael R. Vanderbilt University, School of Medicine, Professor
Six forms of cytochrome P-450, three mitochondrial and three microsomal P-450s, participate in the biosynthesis of steroid hormones in animal organs. This research was designed to investigate the basic mechanism regulating the expression of these steroidogenic P-450s in the cells, and focused on the following two topics.
1. Regulation of expression of steroidogenic P-450 genes.
The main object of the research was the regulation of P-450(11beta), which expresses only in adrenal cortex cells. P-450(SCC), which expresses in all steroidogenic organs, was also examined for comparison. The research was carried out in collaboration with Dr.M.R.Waterman (University of Texas) and Dr.K.L.Parker (Duke University).
Four cis-acting elements, Ad1-Ad4, were identified in the promoter region of P-450(11beta). A protein factor binding to Ad4 was purified from the nuclear extract of adrenal cortex cells, and its amino acid sequence was deduced from the cloned cDNA. Ad4 is present in the promoter region of all steroidogenic P-450s including P-450(SCC) and Ad4BP expresses only in steroidogenic organs. Ad4-Ad4B& system seems to be functional in the expression of steroidogenic P-450s in steroid hormone-producing. cells.
2. Integration of P-450 proteins into microsomal and mitochondrial membranes.
The main object of the research was the mechanism of correct integration of newly synthesized P-450 molecules into the membrane of endoplasmic reticulum. The research was carried out in collaboration with Dr.P.Walter (University of California) and Dr.G. von Heijne (Karolinska Institute).
The function of the amino-terminal signal anchor sequence of P-450 molecule in the integration of newly synthesized molecules was analyzed by the introduction of amino acid mutations into the sequence. The correct insertion of the amino terminal sequence was dependent on the balance between the electric charge at the amino temrinus and the hydrophobicity of the following sequence.