The Involvement of Mig1 from Xanthophyllomyces dendrorhous in Catabolic Repression: An Active Mechanism Contributing to the Regulation of Carotenoid Production.
The red yeast X. dendrorhous is one of the few natural sources of astaxanthin, a carotenoid used in aquaculture for salmonid fish pigmentation and in the cosmetic and pharmaceutical industries for its antioxidant properties. Genetic control of carotenogenesis is well characterized in this yeast; however, little is known about the regulation of the carotenogenesis process. Several lines of evidence have suggested that carotenogenesis is regulated by catabolic repression, and the aim of this work was to identify and functionally characterize the X. dendrorhous MIG1 gene encoding the catabolic repressor Mig1, which mediates transcriptional glucose-dependent repression in other yeasts and fungi. The identified gene encodes a protein of 863 amino acids that demonstrates the characteristic conserved features of Mig1 proteins, and binds in vitro to DNA fragments containing Mig1 boxes. Gene functionality was demonstrated by heterologous complementation in a S. cerevisiae mig1- strain; several aspects of catabolic repression were restored by the X. dendrorhous MIG1 gene. Additionally, a X. dendrorhous mig1- mutant was constructed and demonstrated a higher carotenoid content than the wild-type strain. Most important, the mig1- mutation alleviated the glucose-mediated repression of carotenogenesis in X. dendrorhous: the addition of glucose to mig1- and wild-type cultures promoted the growth of both strains, but carotenoid synthesis was observed only in the mutant strain. Transcriptomic and RT-qPCR analyses revealed that several genes were differentially expressed between X. dendrorhous mig1- and the wild-type strain when cultured with glucose as the sole carbon source. The results obtained in this study demonstrate that catabolic repression in X. dendrorhous is an active process in which the identified MIG1 gene product plays a central role in the regulation of several biological processes, including carotenogenesis.
Laboratorio de Genética, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Jennifer
J
Alcaíno
Laboratorio de Genética, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Natalia
N
Bravo
Laboratorio de Genética, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Pamela
P
Córdova
Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Andrés E
AE
Marcoleta
Laboratorio de Genética, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Gabriela
G
Contreras
Laboratorio de Genética, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Salvador
S
Barahona
Laboratorio de Genética, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Dionisia
D
Sepúlveda
Centro de Biología Molecular Severo Ochoa, Departamento de Biología Molecular (UAM-CSIC), Universidad Autónoma, Madrid, Cantoblanco, España.
María
M
Fernández-Lobato
Laboratorio de Genética, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Marcelo
M
Baeza
Laboratorio de Genética, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Víctor
V
Cifuentes
D000595:Amino Acid Sequence; D001487:Basidiomycota / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000235:genetics; D002338:Carotenoids / Q000096:biosynthesis*; D057465:Catabolite Repression / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D005947:Glucose / Q000378:metabolism; D009154:Mutation; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D024341:Xanthophylls / Q000096:biosynthesis
D005656:Fungal Proteins; D012097:Repressor Proteins; D024341:Xanthophylls; D002338:Carotenoids; C005948:astaxanthine; D005947:Glucose