A set of yeast strains based on Saccharomyces cerevisiae S288C in which commonly used selectable marker genes are deleted by design based on the yeast genome sequence has been constructed and analysed. These strains minimize or eliminate the homology to the corresponding marker genes in commonly used vectors without significantly affecting adjacent gene expression. Because the homology between ...

Transgene technology provides a powerful tool for developing traits that are otherwise difficult to achieve through conventional methods. The development of transgenic plants requires the use of selectable marker genes, as the efficiency of plant transformation is less than optimal for many important species, especially for monocots such as durum wheat (Triticum turgidum var. durum). Many conce...

The fission yeast Schizosaccharomyces pombe is an attractive model organism for studying eukaryotic biology due to the ease of genetic and molecular manipulations (3). In recent years, several selectable markers and promoters have been developed to enhance our ability to manipulate gene expression in this yeast. Recently, Invitrogen (Carlsbad, CA, USA) has developed the SpECTRA S. pombe Expres...

The introduction of defined mutations into open reading frames (ORF) or non-translated regions of the genome is important to study of the structure-function relationship of amino acid residues in proteins or that of sequence motifs at the genome level. We describe a simple two-step method for the introduction of defined single or multiple point mutations into the genome of Saccharomyces cerevis...

Phosphinothricin (PPT) is the active ingredient in bialaphos, which specifically inhibits glutamine synthetase in land plants. We isolated a novel PPT-resistant gene from a soil bacterium, Nocardia sp., and characterized it. The encoded protein, consisting of 177 amino acids, showed significant similarity to bacterial N-acetyltransferases, and we originally designated the gene MAT (methionine s...

Allelic replacement in the Burkholderia genus has been problematic due to the lack of appropriate counter-selectable and selectable markers. The counter-selectable marker sacB, commonly used in gram-negative bacteria, is nonselective on sucrose in many Burkholderia species. In addition, the use of antibiotic resistance markers of clinical importance for the selection of desirable genetic traits...

Gene targeting was used to introduce nonselectable genetic changes into chromosomal loci in mouse embryo-derived stem cells. The nonselectable markers were linked to a selectable marker in both insertion- and replacement-type vectors, and the transfer of the two elements to the Hprt locus was assayed. When insertion vectors were used as substrates, the frequency of transfer was highly dependent...