Cruz, USA). Oligonucleotides were synthesized by Invitrogen or Takara. The kits for DNA purification, gel recovery, plasmid miniprep and A-Tailing modification were obtained from Tiangen (Beijing, China) or Takara (Dalian, China). The kit for yeast plasmid DNA isolation was from Omega Biotech (Victoria BC, Canada). Sequencing was performed by Invitrogen or by SinoGenoMax (Beijing, China). Escherichia. coli DH5a was obtained from Takara. Yeast strain Saccharomyces cerevisiae EBY100 was obtained from Invitrogen.