Title: Characterization of the in vitro transcriptional activity of polymorphic alleles of the human monoamine oxidase-B gene.
Authors: Costa-Mallen, Paola; Kelada, Samir N; Costa, Lucio G; Checkoway, Harvey
Published In Neurosci Lett, (2005 Jul 22-29)
Abstract: The activity of monoamine oxidase-B (MAO-B) enzyme has a high degree of heritability, although no common genetic polymorphisms are present in the MAO-B coding region. The only known polymorphisms in MAO-B gene are a C-1,114T in the 5' region, a variable number of GT repeats in intron 2, and a G/A change in intron 13. The genetically determined differences in MAO-B activity among subjects most likely derive from functional differences conferred by these three MAO-B genetic polymorphisms, or by polymorphisms in trans-acting factors that regulate MAO-B expression. In order to identify differences in transcriptional activity conferred by the MAO-B genetic variants, we cloned alternative alleles at the three polymorphic loci in -1,114, intron 2 and intron 13, and tested them in transfection-luciferase assays in HepG2 hepatoma and 1321N1 astrocytoma cells. The mutant -1,114 allele T had higher activity than allele C in both cell lines, when cloned in pGL3Enhancer. Significant differences in trascriptional activity by intron 2 GT repeat allele were also observed, and varied by cell type and reporter construct. Allele G of intron 13 had significantly higher activity than allele A in both cell lines. These results indicate transcriptional activity differences between MAO-B variant alleles that are naturally occurring in the population.
PubMed ID: 15936531
MeSH Terms: Alleles*; Astrocytoma; Carcinoma, Hepatocellular; Cell Line, Tumor; Comparative Study; Gene Expression/physiology*; Humans; In Vitro; Introns; Monoamine Oxidase/genetics*; Monoamine Oxidase/metabolism; Polymorphism, Genetic*; RNA, Messenger/biosynthesis; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, P.H.S.; Reverse Transcriptase Polymerase Chain Reaction/methods; Trans-Activation (Genetics)/physiology*; Transfection/methods