What does Cre inducible mean?

Inducible Cre activation is achieved using CreER (estrogen receptor) variant, which is only activated after delivery of tamoxifen. This is done through the fusion of a mutated ligand binding domain of the estrogen receptor to the Cre recombinase, resulting in Cre becoming specifically activated by tamoxifen.

Are microglia M1 or M2?

Microglia can be categorized into two opposite types: classical (M1) or alternative (M2), though there’s a continuum of different intermediate phenotypes between M1 and M2, and microglia can transit from one phenotype to another.

What is tamoxifen inducible Cre?

Introduction. Tamoxifen (TAM)-inducible Cre/loxP is one of the most widely used inducible systems for gene regulation. This is in part due to the fact that it enables gene control both spatially and temporally.

Why is tamoxifen used in mice?

Tamoxifen is widely used for the induction of genomic recombination in mice (double-)transgenic for floxed genes and Tamoxifen specific estrogen receptors (ER) coupled to Cre-recombinase (supplemental Table 1) (Hayashi and McMahon 2002).

What is a leaky Cre?

Inducible Cre can be leaky Cre is sequestered in the cytoplasm when it is fused to the ligand binding domain of the estrogen receptor, and enters the nucleus when exposed to tamoxifen.

Are microglia monocytes?

Monocytes and microglia are distinct myeloid components of the innate immune system1,2,3,4. Both cell types are actively involved in neuropathological processes, but their respective contributions to neuronal damage and repair remain poorly resolved5.

How does Cre LOX work?

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).

How long does tamoxifen stay in a mouse?

Our results revealed that tamoxifen and its metabolites were completely degraded within 8 days in young adult C57BL/6J mice, while the age-matched FVB/NJ male mice displayed more effective degradation. Moreover, aged C57BL/6J mice were unable to metabolize all substances within 8 days.

Is Cre toxic?

Cre alone can produce a phenotype Cre toxicity can also occur when expression is high enough to affect cell physiology, or when Cre recognizes genomic sequences that resemble loxP sites. Cre can damage DNA in fibroblasts, gastric cells, and sperm in the absence of any floxed sequence.

Is the constitutive cx3cr1-cre line microglia specific?

No leakiness was reported in those studies. If the YFP reporter line has no spontaneous leakiness, then the constitutive Cx3cr1-Cre line developed by Jung et al. (2000), and which is now available at The Jackson Laboratory, is not microglia specific.

Are microglia involved in epileptogenesis in TSC1 cx3cr1-crecko mice?

However, Cre reporter studies demonstrated that constitutive Cx3cr1 expression affected not only microglia, but also a large percentage of cortical neurons, confounding the role of microglia in epileptogenesis in Tsc1 Cx3cr1-CreCKO mice.

How do microglia influence normal brain function and disease progression?

There is growing interest in understanding how microglia influence normal brain function and disease progression. Several microglia-specific Cx3cr1-Cre lines have been developed and have become indispensable tools in many investiga … Microglia play a pivotal role in maintaining homeostasis of the CNS.

Does pilocarpine cause CX3CR1 expression in microglia?

Yeo et al. (2011)reported that pilocarpine-triggered SE induced very moderate expression of Cx3cr1 in astrocytes, but again the IHC data are puzzling. Nearly 100% of the Cx3cr1-positive cells were astrocytes. Then, where were the microglia? In the absence of a reliable anti-Cx3cr1 antibody, it is hard to draw any conclusions from these studies.

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