The CIITA (Class II Major Histocompatibility Complex Transactivator) gene acts as the "master control switch" for the adaptive immune system. It does not bind DNA directly but functions as a transcriptional coactivator, encoding the CIITA protein, which assembles a multi-protein complex (the enhanceosome) to initiate the expression of MHC class II genes. While constitutively expressed in professional antigen-presenting cells like B cells and dendritic cells, its expression can be induced by interferon-gamma (IFN-γ) in almost any nucleated cell type, such as epithelial or endothelial cells ^[1]. Mutations in CIITA lead to Bare Lymphocyte Syndrome Type II (BLS II), a severe combined immunodeficiency characterized by the absence of MHC II molecules, resulting in a failure of CD4+ T cell development and a compromised immune response ^[2]. Ciita-iCre mice were generated using gene editing technology to replace the TGA stop codon with the P2A-iCre cassette. Under the control of the Ciita gene's regulatory elements, the iCre recombinase (a codon-optimized Cre recombinase) is expressed. When Ciita-iCre mice are crossed with mice containing loxP sites, Cre recombinase-mediated recombination between loxP sites is expected to occur in the antigen-presenting cells (APCs) and Ciita-positive cells in the offspring.

Rbms1 is located on chromosome 2 of mice. SgRNA and ssDNA were designed using Nuclease Technology; Rbms1 conditional knockout mice were obtained by high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.

Ciita is located on chromosome 16 of mice. Nuclease Technology was used to design sgRNA; Ciita knockout mice were obtained by applying high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.

Ciita is located on chromosome 16 of mice. Nuclease Technology was used to design sgRNA; Ciita knockout mice were obtained by applying high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.

Armh4 is located on chromosome 14 of mice. Nuclease Technology will be used to design sgRNA; Armh4 knockout mice will be obtained by applying high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.

Ciita is located on chromosome 16 of mice. SgRNA and ssDNA were designed using Nuclease Technology; Ciita conditional knockout mice were obtained by high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.