Isolation and characterization of a gene specific to lager brewing yeast that encodes a branched-chain amino acid permease.
We found two types of branched-chain amino acid permease gene (BAP2) in the lager brewing yeast Saccharomyces pastorianus BH-225 and cloned one type of BAP2 gene (Lg-BAP2), which is identical to that of Saccharomyces bayanus (by-BAP2-1). The other BAP2 gene of the lager brewing yeast (cer-BAP2) is very similar to the Saccharomyces cerevisiae BAP2 gene. This result substantiates the notion that lager brewing yeast is a hybrid of S. cerevisiae and S. bayanus. The amino acid sequence homology between S. cerevisiae Bap2p and Lg-Bap2p was 88%. The transcription of Lg-BAP2 was not induced by the addition of leucine to the growth medium, while that of cer-BAP2 was induced. The transcription of Lg-BAP2 was repressed by the presence of ethanol and weak organic acid, while that of cer-BAP2 was not affected by these compounds. Furthermore, Northern analysis during beer fermentation revealed that the transcription of Lg-BAP2 was repressed at the beginning of the fermentation, while cer-BAP2 was highly expressed throughout the fermentation. These results suggest that the transcription of Lg-BAP2 is regulated differently from that of cer-BAP2 in lager brewing yeasts.
Kodama
Y
Y
Institute for Fundamental Research, Suntory Research Center, Mishima-gun, Osaka 618-8503, Japan. Yukiko_Kodama@suntory.co.jp
Omura
F
F
Ashikari
T
T
D000595:Amino Acid Sequence; D026905:Amino Acid Transport Systems; D001515:Beer / Q000382:microbiology*; D003001:Cloning, Molecular; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D012440:Saccharomyces / Q000201:enzymology* / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D026905:Amino Acid Transport Systems; C097094:BAP2 protein, S cerevisiae; D026901:Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins