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. elim...

In September 1998 the workshop for “Conditional Genome Alterations” in Cold Spring Harbor had a simple but important take-home message: “Cre works” (Rossant and McMahon, 1999). After several years of careful investigations, geneticists are now certain that the Cre recombinase of the P1 bacteriophage efficiently catalyzes recombination between two of its consensus 34 base pair DNA recognition si...

The prokaryotic beta recombinase catalyzes site-specific recombination between two directly oriented minimal six sites in chromatin-integrated substrates. Here, we demonstrate that an enhanced green fluorescent protein (EGFP)-fused version of beta recombinase (beta-EGFP) is fully active, retaining most specific activity. It is used to develop a recombination-dependent activatable gene expressio...

Common lymphoid progenitors (CLPs) are the first bone marrow precursors in which V(D)J recombinase activity is up-regulated. Here, we show that loss of the transcription factor E47 produces a reduced CLP population that lacks V(D)J recombinase activity and D-J H rearrangements in vivo. Apart from a profound arrest before the pro–B cell stage, other downstream lymphoid progeny of CLPs are still ...

Site-specific recombinases are enzymes that promote precise rearrangements of DNA sequences. They do this by cutting and rejoining the DNA strands at specific positions within a pair of target sites recognized and bound by the recombinase. One group of these enzymes, the serine recombinases, initiates strand exchange by making double-strand breaks in the DNA of the two sites, in an intermediate...

PURPOSE To establish a transgenic mouse line that expresses Cre-recombinase in retinal rod bipolar cells for the generation of rod bipolar cell-specific knockout mutants. METHODS The IRES-Cre-cDNA fragment was inserted into a 173-kb bacterial artificial chromosome (BAC) carrying the intact Pcp2 gene, by using red-mediated recombineering. Transgenic mice were generated with the modified BAC an...

The Xer site-specific recombination system of Escherichia coli is involved in the stable inheritance of circular replicons. Multimeric replicons, produced by homologous recombination, are converted to monomers by the action of two related recombinases XerC and XerD. Site-specific recombination at a locus, dif, within the chromosomal replication terminus region is thought to convert dimeric chro...