Regulation of MAO-A and MAO-B gene expression.
MAO A and B genes are made of 15 exons with identical exon-intron organization. They are located on X-chromosome organized in opposite direction, tail to tail with 24 kb apart. Both promoters are GC-rich and regulated by transcription factor Sp1. However, they have distinctly different features. MAO B gene, but not MAO A gene, has TATA box. MAO B promoter contains two clusters of overlapping Sp1 sites, the CACCC repressor element. Transcription factors Sp1 and Sp4 can activate MAO B promoter activity through the proximal cluster of Sp1 sites and its activation can be repressed by the over-expression of Sp3 and a related family member, BTEB2. Decreased methylation and transcription repressor Sp3 upregulate human MAO B, but not MAO A, gene expression during Caco-2 differentiation. MAO B, but not MAO A gene, could be activated by PMA (phorbol 12-myristate 13-acetate) by protein kinase C, MAPkinase signal transduction pathway involves cJun and Egr-1. The differences in MAO A and B gene regulation may explain the different tissue-specific expression and functions of these two important isoenzymes.
Department of Molecular Pharmacology and Toxicology, Pharmaceutical Science Center, University of Southern California, 1985 Zonal Ave. Los Angeles, California 90033, USA. jcshih@usc.edu
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D000818:Animals; D001483:Base Sequence; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008969:Molecular Sequence Data; D008995:Monoamine Oxidase / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid
D008995:Monoamine Oxidase