Cloning, characterization, and expression of two alpha-amylase genes from Aspergillus niger var. awamori

• Published in: Current genetics Vol. 17; no. 3; pp. 203 - 212
• Main Authors: Korman, D.R, Bayliss, F.T, Barnet, C.C, Carmona, C.L, Kodama, K.H, Royer, T.J, Thompson, S.A, Ward, M, Wilson, L.J, Berka, R.M
• Format: Journal Article
• Language: English
• Published: United States 01.03.1990
• Subjects: alpha-amylase; alpha-Amylases - biosynthesis; alpha-Amylases - genetics; Amino Acid Sequence; Aspergillus niger; Aspergillus niger - enzymology; Aspergillus niger - genetics; Base Sequence; Blotting, Southern; characterization; cloning; Cloning, Molecular; Codon; DNA, Fungal - genetics; Exons; Gene Expression; genes; Genes, Fungal; Introns; Molecular Sequence Data; nucleotide sequences; Restriction Mapping; Sequence Homology, Nucleic Acid; Transformation, Genetic
• ISSN: 0172-8083; 1432-0983
• DOI: 10.1007/BF00312611

Using synthetic oligonucleotide probes, we cloned genomic DNA sequences encoding an alpha-amylase gene from Aspergillus niger var. awamori (A. awamori) on a 5.8 kb EcoRI fragment. Hybridization experiments, using a portion of this cloned fragment to probe DNA from A. awamori, suggested the presence of two alpha-amylase gene copies which were subsequently cloned as 7 kb (designated as amyA) and 4 kb (amyB) HindIII fragments. DNA sequence analysis of the amyA and amyB genes revealed the following: (1) Both genes are arranged as nine exons and eight introns; (2) The nucleotide sequences of amyA and amyB are identical throughout all but the last few nucleotides of their respective coding regions; (3) The amyA and amyB genes from A. awamori share extensive homology (greater than or equal to 98% identity) with the genes encoding Taka-amylase from A. oryzae. In order to test whether both amyA and amyB were functional in the genome, we constructed vectors containing gene fusions of either amyA and amyB to bovine prochymosin cDNA and used these vectors to transform A. awamori. Transformants which contained either the amyA- or amyB-prochymosin gene fusions produced extracellular chymosin, suggesting that both genes are functional.