When fused to the ligand binding domain (LBD) of steroid hormone nuclear receptors, site-specific recombinases (SSRs) acquire a ligand-dependent activity. Here, we describe the use of SSR-LBD fusion proteins in an inducible expression system, introduced into cells in a single step. A single transgene contains a constitutively active, bi-directional enhancer/promoter, which directs expression, o...

Chlorimuronethyl resistance gene is increasingly used as a selectable marker for transformation, especially fungal transformation. Magnaporthe grisea is an important model organism for investigating fungal pathogenicity, and Agrobacterium tumefaciens-mediated transformation (ATMT) is used for functional mutagenesis of the fungus. However, our results showed that rice blast strains collected fro...

Efficient homologous recombination permits the directed introduction of specific mutations into the yeast genome. Here we describe a cloning-free, PCR-based allele replacement method that simplifies allele transfer between yeast strains. The desired allele from one strain is amplified by PCR, along with a selectable/counterselectable marker. After transformation, the resident allele in the targ...

Background: The objective of this study was to develop an efficient selectable marker for transgenic Dunaliella salina. Results: Tests of the sensitivity of D. salina to the antibiotic chloramphenicol and the herbicide Basta® showed that cells (1.0 × 10 cells/ml) treated with 1000 or 1500 μg/ml chloramphenicol died in 8 or 6 days, respectively, whereas D. salina cells (1.0 × 10 cells/ml) treate...

Transformation-associated recombination (TAR) is a cloning technique that allows specific chromosomal regions or genes to be isolated directly from genomic DNA without prior construction of a genomic library. This technique involves homologous recombination during spheroplast transformation between genomic DNA and a TAR vector that has 5' and 3' gene targeting sequences (hooks). Typically, TAR ...

The Janus cassette permits marker-free allelic replacement or knockout in streptomycin-resistant Streptococcus pneumoniae (pneumococcus) through sequential positive and negative selection. Spontaneous revertants of Janus can lead to high level of false-positives during negative selection, which necessitate a time-consuming post-selection screening process. We hypothesized that an additional cou...

Stable cell transfection is used for the expression of exogenous genes or cDNAs in eukaryotic cells. Selection of these transfectants requires a dominant selectable marker. A variety of such markers has been identified and is currently in use. However, many of these are not suitable for all cell types or require unique conditions. Here we describe a simple and versatile dominant selectable mark...