title: Translation initiation factor 5A in Picrorhiza is up-regulated during leaf senescence and in response to abscisic acid.
abstract: Translation initiation, the first step of protein synthesis process is the principal regulatory step controlling translation and involves a pool of translation initiation factors. In plants, from recent studies it is becoming evident that these translation initiation factors impact various aspects of plant growth and development in addition to their role in protein synthesis. Eukaryotic translation initiation factor eIF5A is one such factor which functions in start site selection for the eIF2-GTP-tRNAi ternary complex within the ribosomal-bound preinitiation complex and also stabilizes the binding of GDP to eIF2. In the present study we have cloned and analysed a gene (eIF5a) encoding eIF5A from Picrorhiza (Picrorhiza kurrooa Royle ex Benth.) a medicinal plant of the western Himalayan region. The full length eIF5a cDNA consisted of 838 bp with an open reading frame of 480 bp, 88 bp 5' untranslated region and 270 bp 3' untranslated region. The deduced eIF5A protein contained 159 amino acids with a molecular weight of 17.359 kDa and an isoelectric point of 5.59. Secondary structure analysis revealed eIF5A having 24.53% α-helices, 8.81% β-turns, 23.27% extended strands and 43.40% random coils. pk-eIF5a transcript was found to be expressing during the active growth phase as well as during leaf senescence stage, however, highest expression was observed during leaf senescence stage. Further, its expression was up-regulated in response to exogenous application of abscisic acid. Both high intensity as well as low intensity light decreased the expression of pk-eIF5a. The findings suggest eIF5a to be an important candidate to develop genetic engineering based strategies for delaying leaf senescence.
authors.affiliation: Academy of Scientific and Innovative Research-IHBT (AcSIR-IHBT), India; Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh 176061, India.
authors.forename: Jai
authors.initials: J
authors.lastname: Parkash
authors.affiliation: Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh 176061, India.
authors.forename: Tanmay
authors.initials: T
authors.lastname: Vaidya
authors.affiliation: Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh 176061, India.
authors.forename: Shruti
authors.initials: S
authors.lastname: Kirti
authors.affiliation: Academy of Scientific and Innovative Research-IHBT (AcSIR-IHBT), India; Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh 176061, India. Electronic address: sd_bio@yahoo.com.
authors.forename: Som
authors.initials: S
authors.lastname: Dutt
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D005818:Genetic Engineering; D008027:Light; D008969:Molecular Sequence Data; D010442:Peptide Chain Initiation, Translational / Q000235:genetics*; D010448:Peptide Initiation Factors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D032261:Picrorhiza / Q000235:genetics / Q000254:growth & development*; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development*; D017433:Protein Structure, Secondary; D016601:RNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D000040:Abscisic Acid; D010448:Peptide Initiation Factors; D010937:Plant Growth Regulators; D016601:RNA-Binding Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A
keywords: Abscisic acid; Eukaryotic translation initiation factor 5A; Leaf senescence; Picrorhiza; Translation