Cloning and sequencing of phenol oxidase 1 (pox1) gene from Pleurotus ostreatus

Abstract

The gene (pox1) encoding a phenol oxidase 1 from Pleurotus ostreatus was sequenced and the corresponding pox1-cDNA was also synthesized, cloned and sequenced. The isolated gene is flanked by an upstream region called the promoter (399 bp) prior to the start codon (ATG). The putative metalresponsive elements (MREs) were determined in the promoter region, where MRE 1, 2 and 3 were located in positions -20, -62 and -389, respectively. Functional TATA consensus sequences were recognized in positions -78 and -245, while CAAT consensus sequence was recognized in position -171. The putative GC boxes consensus sequences were recognized in positions -175 and -344, and xenobiotic-responsive elements (XREs) in positions -100 and -270. The pox1-DNA gene consists of 2656 bp, with the coding sequence being interrupted by 19 introns. The nucleotide sequence of cDNA (pox1- cDNA) was found to contain an ORF of 1590 bp capable of coding for a protein of 529 amino acid residues. The signal peptide was predicted to be 23 amino acids in length using SIGNALP 3.0 program. Northern blot analysis revealed that strong transcriptional induction was observed in the coppersupplemented cultures for pox1 gene.

Key words: Pleurotus, cDNA, pox1, gene promoter, putative sequences, northern blot analysis, copper.