Current mouse gene targeting technology is unable to introduce somatic mutations at a chosen time and/or in a given tissue. We report here that conditional site-specific recombination can be achieved in mice using a new version of the Cre/lox system. The Cre recombinase has been fused to a mutated ligand-binding domain of the human estrogen receptor (ER) resulting in a tamoxifen-dependent Cre r...

Abstract Background: Selectable marker gene (SMG) systems are critical for generation of transgenic crops. Transgenic crop production Background: Selectable marker gene (SMG) systems are critical for generation of transgenic crops. Transgenic crop production without using SMG is not economically feasible. However, SMGs are non-essential once an intact transgenic plant has been established. Eli...

Stimulation of recombination by ultraviolet (UV) irradiation was discovered by Jacob and Wollmanl using the phage a. Subsequently recombination in both prokaryotic and eukaryotic organisms has been shown to be stimulated by W light and other agents acting on DNA. A close relationship between the repair of damaged DNA and recombination was established directly by the isolation of ret mutants of ...

Null mutations in three recombination and DNA repair genes were studied to determine their effects on mitotic recombination between the duplicate AdoMet (S-adenosylmethionine) synthetase genes (SAM1 and SAM2) in Saccharomyces cerevisiae. SAM1 and SAM2, located on chromosomes XII and IV, respectively, encode functionally equivalent although differentially regulated AdoMet synthetases. These simi...

HK022, a temperate coliphage related to lambda, forms lysogens by inserting its DNA into the bacterial chromosome through site-specific recombination. The Escherichia coli Fis and phage Xis proteins promote excision of HK022 DNA from the bacterial chromosome. These two proteins also act during lysogenization to prevent a prophage rearrangement: lysogens formed in the absence of either Fis or Xi...

The virally encoded site-specific recombinase Int collaborates with its accessory DNA bending proteins IHF, Xis, and Fis to assemble two distinct, very large, nucleoprotein complexes that carry out either integrative or excisive recombination along regulated and essentially unidirectional pathways. The core of each complex consists of a tetramer of Integrase protein (Int), which is a heterobiva...

Tirapazamine (3-amino-1,2,4-benzotriazine-1,4-dioxide) is a promising hypoxia-selective cytotoxin that has shown significant activity in advanced clinical trials in combination with radiotherapy and cisplatin. The current study aimed to advance our understanding of tirapazamine-induced lesions and the pathways involved in their repair. We show that homologous recombination plays a critical role...

A prophage lambda inserted by homologous recombination near dif, the chromosome dimer resolution site of Escherichia coli, is excised at a frequency that depends on its orientation with respect to dif. In wild-type cells, terminal hyper- (TH) recombination is prophage specific and undetectable by a test involving deletion of chromosomal segments between repeats identical to those used for proph...

Molecular evidence is provided for genomic recombinations in maize cells induced by the yeast FLP/FRT site-specific recombination system. The FLP protein recombined FRT sites previously integrated into the maize genome leading to excision of a selectable marker, the neo gene. NPTII activity was not observed after the successful recombination process; instead, the gusA gene was activated by the ...