title: Overproduction of translation elongation factor 1-alpha (eEF1A) suppresses the peroxisome biogenesis defect in a Hansenula polymorpha pex3 mutant via translational read-through.
abstract: In eukaryotes, elongation factor 1-alpha (eEF1A) is required during the elongation phase of translation. We observed that a portion of the cellular eEF1A colocalizes with purified peroxisomes from the methylotrophic yeast Hansenula polymorpha. We have isolated two genes (TEF1 and TEF2) that encode eEF1A, and which are constitutively expressed. We observed that overproduction of eEF1A suppressed the peroxisome deficient phenotype of an H. polymorpha pex3-1 mutant, which was not observed in a strain deleted for PEX3. The pex3-1 allele contains a UGG to UGA mutation, thereby truncating Pex3p after amino acid 242, suggesting that the suppression effect might be the result of translational read-through. Consistent with this hypothesis, overexpression of the pex3-1 gene itself (including its now untranslated part) partly restored peroxisome biogenesis in a PEX3 null mutant. Subsequent co-overexpression of TEF2 in this strain fully restored its peroxisome biogenesis defect and resulted in the formation of major amounts of full-length Pex3p, presumably via translational read-through.
authors.affiliation: Eukaryotic Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, The Netherlands. j.a.k.w.kiel@rug.nl
authors.forename: Jan A K W
authors.initials: JA
authors.lastname: Kiel
authors.forename: Vladimir I
authors.initials: VI
authors.lastname: Titorenko
authors.forename: Ida J
authors.initials: IJ
authors.lastname: van der Klei
authors.forename: Marten
authors.initials: M
authors.lastname: Veenhuis
mesh_terms: D001483:Base Sequence; D018389:Codon, Nonsense; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000235:genetics*; D046529:Microscopy, Electron, Transmission; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D020648:Peptide Elongation Factor 1 / Q000096:biosynthesis* / Q000235:genetics*; D020675:Peroxisomes / Q000000981:diagnostic imaging / Q000235:genetics / Q000502:physiology*; D010843:Pichia / Q000235:genetics* / Q000648:ultrastructure; D014176:Protein Biosynthesis / Q000235:genetics*; D013489:Suppression, Genetic; D014463:Ultrasonography
chemical_list: D018389:Codon, Nonsense; D004271:DNA, Fungal; D005656:Fungal Proteins; D020648:Peptide Elongation Factor 1