title: Molecular control of copper homeostasis in filamentous fungi: increased expression of a metallothionein gene during aging of Podospora anserina.
abstract: The lifespan of the ascomycete Podospora anserina was previously demonstrated to be significantly increased in a copper-uptake mutant, suggesting that copper is a potential stressor involved in degenerative processes. In order to determine whether changes in copper stress occur in the cells during normal aging of cultures, we cloned and characterized a gene coding for a component of the molecular machinery involved in the control of copper homeostasis. This gene, PaMt1, is a single-copy gene that encodes a metallothionein of 26 amino acids. The coding sequence of PaMt1 is interrupted by a single intron. The deduced amino acid sequence shows a high degree of sequence identity to metallothioneins of the filamentous ascomycete Neurospora crassa and the basidiomycete Agaricus bisporus, and to the N-terminal portion of mammalian metallothioneins. Levels of PaMt1 transcript increase in response to elevated amounts of copper in the growth medium and during aging of wild-type cultures. In contrast, in the long-lived mutant grisea, transcript levels first increase but then decrease again. The ability of wild-type cultures to respond to exogenous copper stress via the induction of PaMt1 transcription is not affected as they grow older.
authors.affiliation: Molekulare Entwicklungsbiologie und Biotechnologie, Johann Wolfgang Goethe-Universität, Botanisches Institut, Frankfurt am Main, Germany.
authors.forename: N B
authors.initials: NB
authors.lastname: Averbeck
authors.forename: C
authors.initials: C
authors.lastname: Borghouts
authors.forename: A
authors.initials: A
authors.lastname: Hamann
authors.forename: V
authors.initials: V
authors.lastname: Specke
authors.forename: H D
authors.initials: HD
authors.lastname: Osiewacz
mesh_terms: D000364:Agaricus / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D003300:Copper / Q000378:metabolism*; D019327:Copper Sulfate / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015723:Gene Library; D006706:Homeostasis; D007438:Introns; D008668:Metallothionein / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009492:Neurospora crassa / Q000235:genetics; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D020037:Sordariales / Q000502:physiology*; D013997:Time Factors; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D003300:Copper; D004247:DNA; D008668:Metallothionein; D001616:beta-Galactosidase; D019327:Copper Sulfate