Lysozyme (LYZ) gene-encoded lysozyme is an antibacterial agent found in human milk and also exists in the spleen, lung, kidney, white blood cells, plasma, saliva, and tears. The protein has antibacterial activity against a variety of bacteria. Mutations in LYZ are associated with hereditary renal amyloidosis. Lyz2 is the ortholog of LYZ in mice, and its expressed tissues include the hematopoietic system, liver, mesothelium, small intestine, and yolk sac. Lyz2-IRES-iCre mice carry an insertion of the IRES-iCre expression element, and when this strain of mice is crossed with mice containing the loxP locus, sequence recombination between loxP loci mediated by Cre recombinase can occur in the bone marrow lineage cells (monocytes, mature macrophages, and granulocytes) of the offspring mice. The homozygous Lyz2-IRES-iCre mice are viable and fertile.

Lysozyme, encoded by the LYZ gene, is an integral component of the innate immune system. Its primary function is to disrupt bacterial cell walls by cleaving the β-1,4-glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine in bacterial peptidoglycan, leading to bacterial lysis. Lysozyme is abundant in various secretions, including tears, saliva, human milk, and mucus, as well as in the cytoplasmic granules of macrophages and polymorphonuclear neutrophils. Cytoplasmic lysozyme expression is high in bone marrow cells, Paneth cells, and a subset of salivary gland cells ^[1-2]. Mice have two lysozyme-encoding genes, Lyz1 and Lyz2, which are highly homologous to the human LYZ gene. Lyz1 is primarily expressed in Paneth cells, while Lyz2 is mainly expressed in myeloid cells. Myeloid-specific expression of Lyz2 is associated with cell-type-specific demethylation of its downstream enhancer. The Lyz2 protein also has lysozyme activity and participates in defense responses against both Gram-negative and Gram-positive bacteria. Lyz2 is expressed in the hematopoietic system, liver, mesothelium, small intestine, and yolk sac of mice ^[3-4]. Lyz2-IRES-CreERT2 mice were generated using gene editing technology to integrate the tamoxifen-inducible CreERT2 recombinase expression element into the 3’UTR of the mouse Lyz2 gene. This mimics the expression pattern of the endogenous gene while maintaining Lyz2 expression. When bred with mice carrying a loxP site-flanked sequence, Cre recombinase-mediated recombination of the flanked sequence occurs in myeloid cells, including monocytes, mature macrophages, and granulocytes, following tamoxifen induction.

Gdf2 is located on chromosome 14 of mice. Nuclease Technology will be used to design sgRNA; Gdf2 knockout mice will be obtained by applying high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.

Lyz2 is located on chromosome 10 of mice. Nuclease Technology will be used to design sgRNA; Lyz2 knockout mice will be obtained by applying high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.

Lyz2 is located on chromosome 10 of mice. SgRNA and ssDNA were designed using Nuclease Technology; Lyz2 conditional knockout mice were obtained by high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.

Pi4k2a is located on chromosome 19 of mice. SgRNA and ssDNA will be designed using Nuclease Technology; Pi4k2a conditional knockout mice will be obtained by high-throughput electroporation of fertilized eggs. After sexual maturity, sperm will be collected for cryopreservation.