title: Modulation of eIF5A1 expression alters xylem abundance in Arabidopsis thaliana.
abstract: Eukaryotic translation initiation factor 5A (eIF5A) is thought to facilitate protein synthesis by participating in the nuclear export of specific mRNAs. In Arabidopsis, there are three isoforms of eIF5A. One of them, AteIF5A1, has been shown to be expressed in vascular tissue, specifically developing vessel members, using GUS as a reporter. In order to determine whether AteIF5A1 plays a role in xylem formation, its full-length cDNA was constitutively over-expressed in transgenic Arabidopsis plants. Microscopic analysis revealed that the cross-sectional area of the xylem in the main inflorescence stems of transgenic plants was 1.9-fold higher than those of corresponding inflorescence stems of wild-type plants. In wild-type stems, the primary xylem typically comprised six cell layers and was approximately 105 mum thick, but increased to 9-11 cell layers, 140-155 mum thick, in transgenic stems. Similarly, the secondary xylem increased from six cell layers, approximately 70 mum thick, in control stems to approximately 9 cell layers, 95-105 mum thick, in transgenic stems. Moreover, constitutive down-regulation of AteIF5A1 using antisense technology resulted in the major suppression of xylem formation compared with control plants, and the antisense transgenic plants were also stunted. These data collectively indicate that eIF5A1 plays a role in xylogenesis.
authors.affiliation: Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Zhongda
authors.initials: Z
authors.lastname: Liu
authors.forename: Jeremy
authors.initials: J
authors.lastname: Duguay
authors.forename: Fengshan
authors.initials: F
authors.lastname: Ma
authors.forename: Tzann-Wei
authors.initials: TW
authors.lastname: Wang
authors.forename: Ruth
authors.initials: R
authors.lastname: Tshin
authors.forename: Marianne T
authors.initials: MT
authors.lastname: Hopkins
authors.forename: Linda
authors.initials: L
authors.lastname: McNamara
authors.forename: John E
authors.initials: JE
authors.lastname: Thompson
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D008969:Molecular Sequence Data; D010448:Peptide Initiation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018547:Plant Stems / Q000166:cytology / Q000378:metabolism; D030821:Plants, Genetically Modified; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation; D052584:Xylem / Q000378:metabolism*; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D029681:Arabidopsis Proteins; D010448:Peptide Initiation Factors; D016601:RNA-Binding Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A