MOLECULAR-CLONING OF THE SECRETED BETA-GALACTOSIDASE GENE FROM THE MYCELIAL FUNGUS PENICILLIUM-CANESCENS

The secreted beta-galactosidase gene from Penicillium canescens was cloned by using synthetic oligonucleotide probes, and its nucleotide sequence was partially determined. The gene was found to be present in the genome as a single copy. Amino acid sequences of the signal peptide (39 residues) and the first 25 amino acid residues of the mature protein were deduced from the nucleotide sequence. Structural analysis of the nucleotide sequence of the beta-galactosidase gene showed that the gene contains an intron 64 bp in length. The site of transcription initiation was found to be located 89 bp ups from the ATG codon. Some characteristics of the signal peptide cleavage mechanism are discussed.