title: Carotenoid synthesis and phytoene synthase activity during mating of Blakeslea trispora.
abstract: Carotenoid formation was investigated in wild type and carotenogenic mutants of Blakeslea trispora after mating (-) and (+) strains. The highest yields of carotenoids, especially β-carotene was observed following mating. In vitro incorporation of geranylgeranyl pyrophosphate into phytoene and β-carotene corresponded to increased carotenogenesis in the mated strains. Immuno determination of phytoene synthase protein levels revealed that the amounts of this enzyme is concurrent with the increases in carotenoid content. In fungi, phytoene synthase together with lycopene cyclase are encoded by a fusion gene crtYB or carRA with two individual domains. These domains were both heterologously expressed in an independent manner and antisera raised against both. These antisera were used, to assess protein levels in mated and non-mated B. trispora. The phytoene synthase domain was detected as an individual soluble protein with a molecular weight of 40 kDa and the lycopene cyclase an individual protein of mass about 30 kDa present in the membrane fraction following sub-cellular fractionation. This result demonstrates a post-translational cleavage of the protein transcribed from a single mRNA into independent functional phytoene synthase and lycopene cyclase.
authors.affiliation: Molecular Biosciences 213, JW Goethe Universität, Frankfurt, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Breitenbach
authors.forename: Paul D
authors.initials: PD
authors.lastname: Fraser
authors.forename: Gerhard
authors.initials: G
authors.lastname: Sandmann
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics / Q000378:metabolism*; D002338:Carotenoids / Q000096:biosynthesis* / Q000302:isolation & purification; D002462:Cell Membrane / Q000378:metabolism; D004789:Enzyme Activation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D007106:Immune Sera / Q000378:metabolism; D019753:Intramolecular Lyases / Q000235:genetics / Q000378:metabolism; D008970:Molecular Weight; D009090:Mucorales / Q000201:enzymology* / Q000235:genetics; D011106:Polyisoprenyl Phosphates / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012995:Solubility
chemical_list: D005656:Fungal Proteins; D007106:Immune Sera; D011106:Polyisoprenyl Phosphates; D012333:RNA, Messenger; D002338:Carotenoids; D019883:Alkyl and Aryl Transferases; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D019753:Intramolecular Lyases; C070925:lycopene cyclase-isomerase; C002963:geranylgeranyl pyrophosphate