Clone And Expression Of The Mel Gene In Saccharomyces Cerevisiae And Detect Angel Dry Yeast

The mel gene encodes tyrosinase, which is the key enzyme of melanin synthesis. The enzyme catalyzes the conversion of L-tyrosine via L-dopa to melanin. There has been growing interest in the melanin in the last few years. Because the expression of mel gene can show black phenotype, the mel gene has been used as a new report gene in research of embryo development of animal, expression and regulation of eukaryotic genome. Our lab has isolated a novel mel gene from Pseudomonas maltophilia, which is the smallest structure gene of mel gene (GenBank Accession No: AF064072). Previous experiments demonstrated that the mel gene could be expressed in Escherichia coli and Bacillus thuringiensis.In this research, we constructed a recombinant plasmid containing mel gene and transformed it into Saccharomyces cerevisiae. The tyrosinase in recombinant strain is determined by SDS-PAGE. This indicates that melanin producted by S. cerevisiae/pAJM relies on the expression of mel gene carried by the recombinant plasmid pAJM. Moreover, we detect the concentration of L-DOPA and melanin in the culture and demonstrate that the melanin produced by S. cerevisiae/pAJM is an L-DOPA-melanin.We also find that the growth of S. cerevisiae/pAJM is always faster than that of S. cerevisiae/pAJ401 in the medium containing tyrosine. By the further experiment, we believe that the mel gene can improve the growth of the strain.We detect two angel dry yeasts and make a conclusion that two yeasts have no recombinant plasmid by abstracting chromosomal DNA and plasmid and PCR.