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Molecular Genetics and Genomics

, Volume 267, Issue 5, pp 593–602 | Cite as

A carotenoid biosynthesis gene cluster in Fusarium fujikuroi: the genes carB and carRA

  •  P. Linnemannstöns
  •  M. Prado
  •  R. Fernández-Martín
  •  B. Tudzynski
  •  J. Avalos
Original Paper

Abstract.

Phytoene synthase, phytoene dehydrogenase and carotene cyclase are three of the four enzyme activities needed to produce the acidic carotenoid neurosporaxanthin from the precursor geranylgeranyl pyrophosphate. In the filamentous fungus Fusarium fujikuroi, these three enzyme activities are encoded by two closely linked genes, carRA and carB, oriented in the same direction in the genome. The two genes are separated by 548 bp and code for two polypeptides of 612 and 541 amino acids, respectively, which are highly similar to the homologous proteins from other filamentous fungi. The ORF of carRA contains a 96-bp insertion that is absent in the other fungal homologues. The 32 additional residues are located in one of the two repeated domains responsible for the cyclase activity in the homologous fungal proteins. We have determined the function of carRA by gene disruption. The resulting mutants were albino and had lost the ability to produce phytoene, as expected from the simultaneous loss of phytoene synthase and carotene cyclase. In the same experiments, we also found transformants in which carB had been deleted. These mutants accumulate phytoene, confirming the function of the gene previously shown by gene-targeted mutagenesis. Expression of carRA and carB is strongly induced by light. Loss of carB or disruption of the carRA ORF led to enhanced expression of the carRA gene, suggesting the existence of a feedback regulatory mechanism.

Carotenoid synthesis Phytoene synthase Phytoene dehydrogenase Carotene cyclase Gene cluster 

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  •  P. Linnemannstöns
    • 1
  •  M. Prado
    • 2
  •  R. Fernández-Martín
    • 2
  •  B. Tudzynski
    • 1
  •  J. Avalos
    • 2
  1. 1.Institut für Botanik, Westfalische Wilhelms-Universität, Schlossgarten 3, D-48149, Münster, Germany
  2. 2.Departamento de Genética, Universidad de Sevilla, Apartado 1095, E-41080 Sevilla, Spain

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