Molecular Biological Studies on new regulatory factors in the control of blood pressure and body fluid with reference to the pathogenesis of hypertension

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D-Amino acid oxidase (EC1.4.3.3, DAO) is a flavoenzyme with FAD as its prosthetic group that catalyzes the oxidative deamination of a wide range of Damino acids. This enzyme was reported to be intracellularly localized in peroxisomes and DAO is regarded as a characteristic marker enzyme of the peroxisomes. The human genome contains a single copy of DAO gene, comprising 11 exons and spanning 20kb. The human DAO locus was assigned to chromosome 12 by screening a panel of Chinese hamster and human somatic cell hybrids with unique sequence primers for PCR analysis. Two sequences of alternating pyrimidine and purine nucleotides, (CA) 20 and (CA) 17, are present in the first intron. In order to search for heterogeneity in the sequences around the CA repeat microsatellite DNA in the human DAO gene, 21 independent human genomic DNAs, comprising Caucasian, Black and Oriental populations were analyzed, and the human DAO gene was found to be an abundant source of polymorphic markers. There are th … More ree other potential sequences for genetic polymorphism in the first intron, namely pentanucleotide ATTTT and 2 poly T tract.Renin-binding protein (RnBP) is a protein that binds to renin, forming a protein complex called high molecular weight renin. In search of its physiological function, gene expression of RnBP in rat aorta were examined by Northern blot hybridization. RnBP gene expression was observed in rat aorta, in addition to kidney, adrenal gland, brain and ovary. The arterial endothelial cells derived from porcine aorta exhibited high level of RnBP gene expression, 40% of the level observed in the kidney. In order to study renin gene expression in relation to that of RnBP,porcine renin cDNA fragment was isolated by RT-PCR analysis of porcine kidney mRNA,followed by determination of the nucleotide sequence for porcine renin. Finally, the RT-PCR analysis of porcine renin mRNA in endothelial cells has shown that renin gene is also expressed in the same endothelium. RnBP gene expression was shown to be up-regulated by Angiotens in II and 8-bromo cAMP in cultured endothelial cells. RnBP,therefore, may participate in blood pressure regulation at vascular endothelium as a member of vascular reninangiotensin system. Less