Abstract:To study the native promoter of xylanase II of Trichoderma asperellum,cloning and sequence analysis of xylanase II structural gene and its 5’ flanking region was performed.On the basis of the genomic conserved sequence of Trichoderma spp.,degenerate PCR was designed to amplify the xylanase II structural gene and its 5′flanking region of Trichoderma asperellum.The product was cloned into T vector and confirmed by EcoR I digestion.Sequence analysis showed that cloned fragment was 1 875 bp long,comprising the 795 bp xylanase II structure gene and its 1 080 bp 5’flanking region.The structure gene encoded a polypeptide of 223 amino acids,where the Glyco-hydro-11 superfamily domains were detected.In the 5’ flanking region,core promoter region,transcriptional start site,CAAT-Box and TATA-Box were detected.Several typical transcriptional factor binding domain,such as CreI,AreA,XlnR,Ace1,AlcR were also found.The 1080 bp 5’ flanking region was a typical promoter.The isolation of this native promoter can benefit the development of an efficient Trichoderma asperellum host system for gene expression.
