title: PCR-mediated seamless gene deletion and marker recycling in Saccharomyces cerevisiae.
abstract: Repeated gene manipulations can be performed in yeast by excision of an introduced marker. Cassette modules containing a marker flanked by two direct repeat sequences of hisG or loxP have often been used for marker recycling, but these leave one copy of the repeats in the chromosome after excision. Genomic copies of a repeat can cause increased mistargeting of constructs containing the same repeats or unexpected chromosomal rearrangements via intra- or interchromosomal recombinations. Here, we describe a novel marker recycling procedure that leaves no scar in the genome, which we have designated seamless gene deletion. A 40 base sequence derived from an adjacent region to the targeted locus was placed in an integrating construct to generate direct repeats after integration. Seamless HIS3 deletion was achieved via a PCR fragment that consisted of a URA3 marker attached to a 40 base repeat-generating sequence flanked by HIS3 targeting sequences at both ends. Transformation of the designed construct resulted in his3 disruption and the generation of 40 base direct repeats on both sides of URA3 in the targeted locus. The resulting his3::URA3 disruptants were plated on 5-fluoroorotic acid medium to select for URA3 loss. All the selected colonies had lost URA3 precisely by recombination between the repeats, resulting in his3 deletion without any extraneous sequences left behind in the chromosome.
authors.affiliation: Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube 755-8611, Japan. rinji@yamaguchi-u.ac.jp
authors.forename: Rinji
authors.initials: R
authors.lastname: Akada
authors.forename: Takao
authors.initials: T
authors.lastname: Kitagawa
authors.forename: Shohei
authors.initials: S
authors.lastname: Kaneko
authors.forename: Daiso
authors.initials: D
authors.lastname: Toyonaga
authors.forename: Sachiko
authors.initials: S
authors.lastname: Ito
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Kakihara
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hoshida
authors.forename: Shigeru
authors.initials: S
authors.lastname: Morimura
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kondo
authors.forename: Kenji
authors.initials: K
authors.lastname: Kida
mesh_terms: D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics; D017353:Gene Deletion; D005819:Genetic Markers; D016254:Mutagenesis, Insertional / Q000379:methods; D009963:Orotic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics*
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D005819:Genetic Markers; D009963:Orotic Acid; C001242:5-fluoroorotic acid