title: The 5'UTR Intron of Arabidopsis GGT1 Aminotransferase Enhances Promoter Activity by Recruiting RNA Polymerase II.
abstract: Photorespiration is essential for the detoxification of glycolate and recycling of carbon to the Calvin Benson Bassham cycle. Enzymes participating in the pathway have been identified, and investigations now focus on the regulation of photorespiration by transporters and metabolites. However, regulation of photorespiration on the gene level has not been intensively studied. Here, we show that maximum transcript abundance of Glu:glyoxylate aminotransferase 1 (GGT1) is regulated by intron-mediated enhancement (IME) of the 5' leader intron rather than by regulatory elements in the 5' upstream region. The intron is rich in CT-stretches and contains the motif TGTGATTTG that is highly similar to the IME-related motif TTNGATYTG. The GGT1 intron also confers leaf-specific expression of foreign promoters. Quantitative PCR analysis and GUS activity measurements revealed that IME of the GGT1 5'UTR intron is controlled on the transcriptional level. IME by the GGT1 5'UTR intron was at least 2-fold. Chromatin immunoprecipitation experiments showed that the abundance of RNA polymerase II binding to the intron-less construct is reduced.
authors.affiliation: Leibniz University Hannover, Institute of Botany, 30419 Hannover, Germany m.laxa@botanik.uni-hannover.de.
authors.forename: Miriam
authors.initials: M
authors.lastname: Laxa
authors.affiliation: Leibniz University Hannover, Institute of Botany, 30419 Hannover, Germany.
authors.forename: Kristin
authors.initials: K
authors.lastname: Müller
authors.affiliation: Leibniz University Hannover, Institute of Botany, 30419 Hannover, Germany.
authors.forename: Natalie
authors.initials: N
authors.lastname: Lange
authors.affiliation: Leibniz University Hannover, Institute of Botany, 30419 Hannover, Germany.
authors.forename: Lennart
authors.initials: L
authors.lastname: Doering
authors.affiliation: Leibniz University Hannover, Institute of Botany, 30419 Hannover, Germany.
authors.forename: Jan Thomas
authors.initials: JT
authors.lastname: Pruscha
authors.affiliation: Leibniz University Hannover, Institute of Botany, 30419 Hannover, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Peterhänsel
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D007438:Introns / Q000235:genetics*; D059372:Nucleotide Motifs / Q000235:genetics; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D012319:RNA Polymerase II / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D000637:Transaminases / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D020121:5' Untranslated Regions; C520630:At1g23310 protein, Arabidopsis; D000637:Transaminases; D012319:RNA Polymerase II