The TAG stop codon was replaced with "3xGGGGS-EGFP" cassette. Enhanced green fluorescent protein (EGFP) is expressed under the regulatory control of Adgrg3 gene elements, without impacting the endogenous expression of the Adgrg3 gene. This model enables EGFP fluorescence protein tracing studies.

Adgrl2-3xGGGGS-mCherry mice are constructed by replacing the partial exon 1 coding region of the mouse Adgrl2 gene with HA signal peptide - HA tag - Mouse Adgrl2 CDS (without signal peptide) - 3xGGGGS - mCherry - rBG pA cassette using gene editing technology. The Adgrl2-3xGGGGS-mCherry mouse carries a red fluorescent protein (mCherry) expression cassette, making it a precise research model that maintains protein function while offering fluorescence visualization. This model is valuable for several key areas of study. For instance, it can be used for the spatio-temporal dynamic analysis of the Adgrl2 gene expression profile. Researchers can also utilize it for investigating neuronal development and synapse formation mechanisms. Furthermore, it enables live-animal dynamic tracking and real-time imaging observation, providing invaluable insights. Lastly, this model is well-suited for systematic studies of protein interaction networks and downstream signaling pathways.

The AGRP gene encodes Agouti-related protein (AgRP), a neuropeptide produced by AgRP/NPY neurons in the brain, primarily expressed in the arcuate nucleus of the hypothalamus, kidneys, and adrenal glands. Studies have shown that AGRP gene expression significantly increases during starvation and rapidly decreases after feeding. AgRP is synthesized exclusively in the ventromedial part of the arcuate nucleus in cells containing neuropeptide Y (NPY) and is co-expressed with NPY, playing a role in increasing appetite, reducing metabolism, and decreasing energy expenditure. The Agrp-IRES-CreERT2-P2A-tdTomato mouse model was created by integrating the IRES-CreERT2-P2A-tdTomato gene expression cassette into the mouse Agrp gene. Under the control of the mouse endogenous Agrp gene regulatory elements, this mouse expresses tamoxifen-inducible CreERT2 recombinase. Additionally, the expression cassette includes a red fluorescent protein (tdTomato) expression element for lineage tracing of Agrp-positive cells. When Agrp-IRES-CreERT2-P2A-tdTomato mice are crossed with mice containing loxP sites, tamoxifen induction can trigger Cre recombinase-mediated sequence recombination between loxP sites in AgRP-positive neurons of the offspring.

The TAA stop codon was replaced with the "P2A-EGFP-T2A-iCre" cassette. Cre recombinase and enhanced green fluorescent protein (EGFP) are expressed under the regulatory control of Alas2 gene elements, without impacting the endogenous expression of the Alas2 gene. In addition to studies of Cre recombinase-mediated gene recombination, this model can also be used for EGFP fluorescent protein tracing studies.

The P2A-3xSV40 NLS-mScarlet cassette was inserted upstream of TGA stop codon. Nuclear-localized mScarlet is expressed under the regulatory control of Alpl gene elements in this mouse model, without impacting endogenous Alpl gene expression. This localization is achieved through the Nuclear Localization Signal (NLS), which efficiently targets mScarlet to the cell nucleus. This enables mScarlet fluorescence protein nuclear tracing studies.

The TAG stop codon was replaced with the T2A-dgCre (DHFR-EGFP-Cre) cassette. Cre recombinase and enhanced green fluorescent protein (EGFP) are expressed under the regulatory control of Calb1 gene elements, without impacting the endogenous expression of the Calb1 gene. The DHFR (dihydrofolate reductase) fragment, derived from the N-terminal 159 amino acids of E. coli ecDHFR, functions as a destabilizing domain (DD). In the absence of specific ligands like TMP (Trimethoprim), this fragment leads to the rapid proteasomal degradation of Cre recombinase. This mechanism allows for the temporal-specific induction of Cre recombinase activity by regulating DHFR-Cre stability with small molecules such as TMP. In addition to studies of Cre recombinase-mediated gene recombination, this model can also be used for EGFP fluorescent protein tracing studies.

The IRES-CreERT2-P2A-EGFP-WPRE-BGH pA cassette was inserted 60~100bp downstream of the TGA stop codon. CreERT2 recombinase and enhanced green fluorescent protein (EGFP) are expressed under the regulatory control of Car1 gene elements. This model is a Tamoxifen-inducible Cre mouse, and when crossed with mice containing loxP sites, the offspring mice are expected to undergo sequence recombination between loxP sites mediated by Cre recombinase in Car1-positive cells following Tamoxifen induction. In addition to studies of Cre recombinase-mediated gene recombination, this model can also be used for EGFP fluorescent protein tracing studies.

The TAG stop codon was replaced with “P2A-EGFP-IRES-loxP-6xSV40 pA-loxP-DTR” cassette. Upstream of the DTR (diphtheria toxin receptor) gene lies a loxP-Stop-loxP cassette that blocks DTR transcription and expression. In the absence of Cre recombinase, the Ccr7 promoter drives EGFP expression, labeling Ccr7-positive cells with green fluorescence. Upon Cre recombination, Cre-mediated deletion of the loxP-flanked stop (LSL) element enables DTR expression in Cre-positive cells. Intravenous administration of diphtheria toxin (DT) then selectively ablates these cells.

The region approximately 60~100 bp downstream of the TGA stop codon was replaced with the "IRES-iCreERT2-P2A-EGFP-WPRE-BGH pA" cassette. CreERT2 recombinase and enhanced green fluorescent protein (EGFP) are expressed under the regulatory control of Cd209a gene elements.

The "IRES-Cre-P2A-EGFP-rBG pA" cassette was inserted downstream of the TGA of mouse Col10a1 gene.