title: D-galactose catabolism in Penicillium chrysogenum: Expression analysis of the structural genes of the Leloir pathway.
abstract: In this study, we analyzed the expression of the structural genes encoding the five enzymes comprising the Leloir pathway of D-galactose catabolism in the industrial cell factory Penicillium chrysogenum on various carbon sources. The genome of P. chrysogenum contains a putative galactokinase gene at the annotated locus Pc13g10140, the product of which shows strong structural similarity to yeast galactokinase that was expressed on lactose and D-galactose only. The expression profile of the galactose-1-phosphate uridylyl transferase gene at annotated locus Pc15g00140 was essentially similar to that of galactokinase. This is in contrast to the results from other fungi such as Aspergillus nidulans, Trichoderma reesei and A. niger, where the ortholog galactokinase and galactose-1-phosphate uridylyl transferase genes were constitutively expressed. As for the UDP-galactose-4-epimerase encoding gene, five candidates were identified. We could not detect Pc16g12790, Pc21g12170 and Pc20g06140 expression on any of the carbon sources tested, while for the other two loci (Pc21g10370 and Pc18g01080) transcripts were clearly observed under all tested conditions. Like the 4-epimerase specified at locus Pc21g10370, the other two structural Leloir pathway genes - UDP-glucose pyrophosphorylase (Pc21g12790) and phosphoglucomutase (Pc18g01390) - were expressed constitutively at high levels as can be expected from their indispensable function in fungal cell wall formation.
authors.affiliation: Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen , H-4032, P.O. Box 64, Debrecen , Hungary.
authors.forename: Ágota
authors.initials: Á
authors.lastname: Jónás
authors.affiliation: Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen , H-4032, P.O. Box 64, Debrecen , Hungary.
authors.forename: Erzsébet
authors.initials: E
authors.lastname: Fekete
authors.affiliation: Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen , H-4032, P.O. Box 64, Debrecen , Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Németh
authors.affiliation: Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen , H-4032, P.O. Box 64, Debrecen , Hungary.
authors.forename: Michel
authors.initials: M
authors.lastname: Flipphi
authors.affiliation: Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen , H-4032, P.O. Box 64, Debrecen , Hungary.
authors.forename: Levente
authors.initials: L
authors.lastname: Karaffa
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004798:Enzymes / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation; D005686:Galactokinase / Q000235:genetics / Q000378:metabolism; D005690:Galactose / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D009713:Nucleotidyltransferases / Q000235:genetics / Q000378:metabolism; D010408:Penicillium chrysogenum / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D010733:Phosphoglucomutase / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D013997:Time Factors; D014534:UDPglucose 4-Epimerase / Q000235:genetics / Q000378:metabolism; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004798:Enzymes; D005686:Galactokinase; D009713:Nucleotidyltransferases; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase; D014534:UDPglucose 4-Epimerase; D010733:Phosphoglucomutase; D005690:Galactose
keywords: D-galactose; Leloir pathway; Penicillium chrysogenum; lactose