Expression of the carG gene, encoding geranylgeranyl pyrophosphate synthase, is up-regulated by blue light in Mucor circinelloides.
A new structural gene, carG, involved in the biosynthesis of carotenoids in the fungus Mucor circinelloides was isolated by heterologous hybridisation, using a probe derived from the Gibberella fujikuroi ggs1 gene. Functional analyses in Escherichia coli showed that the encoded protein has geranylgeranyl pyrophosphate (GGPP) synthase activity. A comparison of the deduced protein with other GGPP synthases suggested that the carG gene might have evolved from other larger genes present in some fungi. The analysis of carG mRNA accumulation after blue light irradiation showed that the expression of this gene is up-regulated by blue light, as happens with the other structural genes involved in carotenogenesis in M. circinelloides. Analysis of the promoter region revealed the presence of several APE-like sequences, which participate in the blue-light regulation of the expression of different fungal genes. These sequences are also present in the above-mentioned Mucor genes and strongly support the idea that this gene plays an important role in the regulation of carotenoid synthesis, despite belonging to a more general metabolic pathway.
Velayos
Antonio
A
Area de Genética, Departamento de Microbiología y Genética, Universidad de Salamanca, Avenida del Campo Charro s/n, 37007 Salamanca, Spain.
Papp
Tamás
T
Aguilar-Elena
Raúl
R
Fuentes-Vicente
Mónica
M
Eslava
Arturo P
AP
Iturriaga
Enrique A
EA
Alvarez
María Isabel
MI
D019883:Alkyl and Aryl Transferases / Q000235:genetics; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002338:Carotenoids / Q000737:chemistry; D017931:DNA Primers; D004122:Dimethylallyltranstransferase / Q000235:genetics*; D051231:Farnesyltranstransferase; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D005816:Genetic Complementation Test; D008027:Light; D008969:Molecular Sequence Data; D009089:Mucor / Q000235:genetics*; D009693:Nucleic Acid Hybridization / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D015854:Up-Regulation
D017931:DNA Primers; D002338:Carotenoids; D019883:Alkyl and Aryl Transferases; D004122:Dimethylallyltranstransferase; D051231:Farnesyltranstransferase