Portal de Periódicos da CAPES

Isolation and analysis of xln R, encoding a transcriptional activator co‐ordinating xylanolytic expression in Aspergillus niger

1998; Wiley; Volume: 27; Issue: 1 Linguagem: Inglês

10.1046/j.1365-2958.1998.00666.x

1365-2958

Noël N. M. E. van Peij, Jaap Visser, Leo H. de Graaff,

Enzyme Production and Characterization

Complementation by transformation of an Aspergillus niger mutant lacking xylanolytic activity led to the isolation of the xln R gene. The xln R gene encodes a polypeptide of 875 amino acids capable of forming a zinc binuclear cluster domain with similarity to the zinc clusters of the GAL4 superfamily of transcription factors. The XlnR‐binding site 5′‐GGCTAAA‐3′ was deduced after electrophoretic mobility shift assays, DNase I footprinting and comparison of various xylanolytic promoters. The importance of the second G within the presumed XlnR binding site 5′‐GGCTAAA‐3′ was confirmed in vitro and in vivo . The 5′‐GGCTAAA‐3′ consensus sequence is found within several xylanolytic promoters of various Aspergillus species and Penicillium chrysogenum . Therefore, this sequence may be an important and conserved cis ‐acting element in induction of xylanolytic genes in filamentous fungi. Our results indicate that XlnR is a transcriptional activator of the xylanolytic system in A . niger .