How does the Cre system work?
How does the Cre system work?
The Cre protein is a site-specific DNA recombinase that can catalyse the recombination of DNA between specific sites in a DNA molecule. These sites, known as loxP sequences, contain specific binding sites for Cre that surround a directional core sequence where recombination can occur.
What is Cre structure?
The structure of the Cre–loxA complex reveals two Cre molecules bound to a single loxA site (Fig. 2). Each Cre molecule contacts the outermost 15 base pairs of one loxA half-site, which includes the 13-base-pair inverted-repeat sequence and the first two base pairs of the central strand-exchange region.
How the CRE LOX system works?
General principle of Cre-loxP system Concerning the mechanism of Cre-loxP system, a single Cre recombinase recognizes two directly repeated loxP site, then the Cre excises the loxP flanked (floxed) DNA, thus creating two types of DNA with circular, excised and inactivated gene Y (Figure 1A).
What does Cre enzyme do?
Cre Recombinase is a Type I topoisomerase from bacteriophage P1 that catalyzes the site-specific recombination of DNA between loxP sites (1). The enzyme requires no energy cofactors and Cre-mediated recombination quickly reaches equilibrium between substrate and reaction products (2).
What is a Cre line?
Cre-driver lines: A special type of transgenic mouse As different neurons have different cellular machinery to activate and express certain genes, Cre-recombinase was targeted to specific neuronal (or other brain cell types) with this in mind.
What are Cre mouse lines?
Cre-expressing mouse lines are thus often referred to as “drivers” because they will mediate recombination and drive genomic alterations as well as corresponding functional consequences.
What is a Cre driver?
What is Cre mouse?
A Cre mouse contains a Cre recombinase transgene under the direction of a tissue-specific promoter; a loxP mouse contains two loxP sites that flank a genomic segment of interest, the “floxed” locus. Typically, Cre and loxP mice are produced by using transgenic technology (Nagy 2000).
What is Cre in biology?
Cre recombinase is a tyrosine recombinase isolated from the bacteriophage P1 that catalyzes the cleavage and ligation of DNA at specific nucleotide recognition sites, loxP sites, via phosphoryl transfer (Hoess et al., 1990). From: Methods in Cell Biology, 2009.
Is Cre a restriction enzyme?
Cre recom- bines the short linear segment into the circular DNA episomes, thereby lin- earizing the episome (Figure 1). Hence, Cre can act like a restriction enzyme that recognizes a 34-bp recognition se- quence.
What is CD4 Cre?
CD4-Cre transgenic mice contain CD4 enhancer, promoter and silencer sequences driving the expression of a Cre recombinase gene. Hemizygotes are viable and fertile. Specifically, Cre recombinase expression is observed in CD4-expressing T cells during sequential stages of T cell development in lymphoid tissues.
How are Cre mice generated?
In this system, a region of interest flanked by two lox sites (floxed) is deleted or inverted by Cre-mediated recombination, leading to gene knockout only in a Cre-expressing cell. In general, Cre/lox mice are generated by mating a Cre-driver mouse with a flox mouse.