ThefaeA gene fromAspergillus niger encoding a feruloyl esterase with activity on xylan and pectin is subject to a complex system of regulation
✍ Scribed by de Vries, Ronald P; Faulds, Craig B; Visser, Jaap
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 98 KB
- Volume
- 79
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
Cinnamoyl esterases play a role in the complete degradation of plant cell wall polysaccharides (xylan and pectin) by micro-organisms. The induction and repression of a gene encoding a feruloyl esterase from Aspergillus niger (faeA), which encodes an enzyme with activity on both xylan and pectin, has been studied using activity measurements and Northern analysis. The gene was expressed on xylan as well as on pectin. The expression on xylan was much higher than on pectin, suggesting that xylan is the preferred substrate. Northern analysis demonstrated that the gene is expressed on xylose and ferulic acid. This indicates the presence of two systems for induction, a xylan/ xylose speciüc system (XlnR) and a ferulic acid speciüc system. Addition of ferulic acid enhanced the induction on xylan, indicating a positive interaction between the two inducing systems. Glucose represses the induction of faeA on xylose and ferulic acid. A comparison of the expression of faeA in the A niger wild-type strain and in a carbon catabolite derepressed mutant of A niger demonstrated that repression of faeA expression is indeed mediated by CreA.