title: Lovastatin insensitive 1, a Novel pentatricopeptide repeat protein, is a potential regulatory factor of isoprenoid biosynthesis in Arabidopsis.
abstract: Higher plants have two metabolic pathways for isoprenoid biosynthesis: the cytosolic mevalonate (MVA) pathway and the plastidal non-mevalonate (MEP) pathway. Despite the compartmentalization of these two pathways, metabolic flow occurs between them. However, little is known about the mechanisms that regulate the two pathways and the metabolic cross-talk. To identify such regulatory mechanisms, we isolated and characterized the Arabidopsis T-DNA insertion mutant lovastatin insensitive 1 (loi1), which is resistant to lovastatin and clomazone, inhibitors of the MVA and MEP pathways, respectively. The accumulation of the major products of these pathways, i.e. sterols and chlorophyll, was less affected by lovastatin and clomazone, respectively, in loi1 than in the wild type. Furthermore, the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity analysis showed higher activity of HMGR in loi1-1 treated with lovastatin than that in the WT. We consider that the lovastatin-resistant phenotype of loi1-1 was derived from this post-transcriptional up-regulation of HMGR. The LOI1 gene encodes a novel pentatricopeptide repeat (PPR) protein. PPR proteins are thought to regulate the expression of genes encoded in organelle genomes by post-transcriptional regulation in mitochondria or plastids. Our results demonstrate that LOI1 is predicted to localize in mitochondria and has the ability to bind single-stranded nucleic acids. Our investigation revealed that the post-transcriptional regulation of mitochondrial RNA may be involved in isoprenoid biosynthesis in both the MVA and MEP pathways.
authors.affiliation: RIKEN Plant Science Center, 1-7-22, Suehirocho, Tsurumi-ku, Yokohama, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Masashi
authors.initials: M
authors.lastname: Suzuki
authors.forename: Jianwei
authors.initials: J
authors.lastname: Tang
authors.forename: Noriko
authors.initials: N
authors.lastname: Nagata
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ohyama
authors.forename: Hikaru
authors.initials: H
authors.lastname: Seki
authors.forename: Reiko
authors.initials: R
authors.lastname: Kiuchi
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Kaneko
authors.forename: Miki
authors.initials: M
authors.lastname: Nakazawa
authors.forename: Minami
authors.initials: M
authors.lastname: Matsui
authors.forename: Shogo
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Shigeo
authors.initials: S
authors.lastname: Yoshida
authors.forename: Toshiya
authors.initials: T
authors.lastname: Muranaka
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D017931:DNA Primers; D004269:DNA, Bacterial; D011106:Polyisoprenyl Phosphates / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic
chemical_list: D029681:Arabidopsis Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D011106:Polyisoprenyl Phosphates; C036483:T-DNA