Article Figures & Data
Figures
- Fig. 1.
Northern blot analysis of expression of A. niger genes encoding cellulose- and xylan-degrading enzymes. (A) Time course of induction in A. nigerNW205::130 (wt) and NXA1-4 (xlnR1) (a loss-of-function mutant). Both strains were cultured for 18 h in medium containing 3% d-fructose (Fr), and mycelia were subsequently transferred to medium containing 1% xylan (Xa) or 1%d-xylose (Xo) and incubated for the times indicated. Each lane contained 10 μg of total RNA, which was checked by hybridization with the 18S rRNA probe. Blots were hybridized with gene-specific probes as indicated. (B) Comparison of expression of genes encoding cellulose- and xylan-degrading enzymes in A. niger N902 (wt), NXA1-4 (xlnR1), and N902-pIM230-25.12 (XlnR+) (N902 with multiple copies of xlnR) upon transfer to medium containing 1% d-xylose for 6 h after growth for 18 h in medium containing 1%d-fructose. A Northern blot analysis was performed exactly as described above. The signal intensities of the different blots cannot be compared to each other due to the unknown specific activities of the probes used and the different exposure times used for the various blots.
Tables
- Table 1.
Probes used in Northern blot analysis
Gene EMBL accession no. Enzyme encoded Fragment used Reference abfB X74777 α-l-Arabinofuranosidase B 1.7-kb EcoRI-XhoI 15 aguA Y15405 α-Glucuronidase A 0.8-kbEcoRV-KpnIa 12 axeA A22880 Acetylxylan esterase A 1.5-kbHindIIIa,b 9 axhA Z78011 Arabinoxylan hydrolase A 1.2-kbEcoRI-XhoI 17 bglA β-Glucosidase A 1.0-kbNcoI-SstI This study eglA AJ224451 Endoglucanase A 0.9-kbXhoI This study eglB AJ224452 Endoglucanase B 1.1-kbEcoRI-XhoI This study faeA Y09330 Feruloyl esterase A 0.5-kbEcoRV-XhoIa 11 xlnB D38071 Endoxylanase B 0.9-kbEcoRI-XhoI 24 xlnC Endoxylanase C 1.2-kbEcoRI-XhoI 18 xlnD Z84377 β-Xylosidase D 2.8-kbPstI-NsiIa 43 18S rRNA X78538 18S rRNA subunit 0.7-kbEcoRI 33 - Table 2.
Putative XlnR binding sites in the upstream region of XlnR-controlled genes
Gene XlnR binding site Position(s)a aguA GGCTAAa −276 axeA GGCTAAt −261 (R) axhA GGCTAAt −340 GGCTAAg −850 (R) eglA GGCTAAg −710 eglB GGCTAAg −128 faeA GGCTAAa −265, −225 xlnB GGCTAAa −124, −216 xlnC GGCTAAt −290 GGCTAAg −500 xlnD GGCTAAa −133, −147 ↵a Position relative to the ATG translation start codon. (R) indicates the opposite orientation of the putative XlnR binding site.
