Functional analysis of the egl3 upstream region in filamentous fungus Trichoderma reesei.
In the filamentous fungus Trichoderma reesei, endoglucanase III (EGIII) is coordinately expressed with other cellulases during growth on cellulose, its derivatives, and L-sorbose. To elucidate EGIII induction mechanism, we cloned and sequenced the upstream region of egl3 encoding EGIII. Two GGCTAA motifs, a putative binding site for ACEII and xylanase regulator Xyr1, were found on the template strand of the egl3 upstream region. Deletion analysis of the egl3 upstream region using the beta-glucuronidase (GUS) reporter system revealed that removal of regions containing the GGCTAA motifs and the region between -1,045 and -1,002 bp containing GGCTAT motif severely affected GUS inducibility. Furthermore, mutation of the two GGCTAA motifs and the GGCTAT motif of this region led to a significant decrease in GUS activity. These data indicate that both GGCTAA and GGCTAT are key motifs for egl3 expression, and that egl3 induction may also be controlled by Xyr1. This hypothesis was supported by in vitro electrophoretic mobility shift assay, in which heterologously expressed Xyr1 specifically bound not only GGCTAA but also GGCTAT motif.
Shida
Yosuke
Y
Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, 940-2188, Japan.
Furukawa
Takanori
T
Ogasawara
Wataru
W
Kato
Masashi
M
Kobayashi
Tetsuo
T
Okada
Hirofumi
H
Morikawa
Yasushi
Y
D024509:3' Flanking Region; D024506:5' Flanking Region; D001483:Base Sequence; D002480:Cellulase / Q000235:genetics*; D003001:Cloning, Molecular; D016384:Consensus Sequence; D024202:Electrophoretic Mobility Shift Assay; D015971:Gene Expression Regulation, Enzymologic; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D020218:Response Elements; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D015533:Transcriptional Activation; D014242:Trichoderma / Q000235:genetics*
D002480:Cellulase