The FGFR1 gene provides instructions for the synthesis of the fibroblast growth factor receptor 1, a member of the receptor tyrosine kinase (RTK) family. This protein is characterized by an extracellular region with three immunoglobulin-like domains for ligand binding, a single transmembrane segment, and an intracellular tyrosine kinase domain that triggers downstream signaling cascades like the MAPK/ERK and PI3K/AKT pathways. FGFR1 is widely expressed across diverse tissues, with particularly high levels in the developing mesoderm, skeletal system, and the central nervous system, where it is essential for the migration of gonadotropin-releasing hormone (GnRH) neurons and olfactory bulb development ^[1]. Functionally, it acts as a master regulator of cell proliferation, differentiation, and survival, playing a pivotal role in embryonic limb induction and adult tissue homeostasis ^[2]. Mutations or chromosomal aberrations in FGFR1 are linked to a diverse array of diseases: gain-of-function mutations cause craniosynostosis syndromes like Pfeiffer and Jackson-Weiss syndromes, while loss-of-function variants lead to Kallmann syndrome (characterized by delayed puberty and an absent sense of smell) ^[3]. Additionally, FGFR1 gene amplifications and rearrangements are significant oncogenic drivers in various cancers, including squamous cell lung cancer, certain breast cancers, and 8p11 myeloproliferative syndrome ^[4]. The B6-huFGFR1 mouse is a humanized model constructed through gene-editing technology, in which the mouse Fgfr1 endogenous extracellular domain genomic DNA is replaced with the human FGFR1 extracellular domain genomic DNA. This model can be used for research on craniosynostosis syndromes, Kallmann syndrome, and various cancers, as well as for screening, development, and preclinical evaluation of FGFR1-targeted therapeutics.

The FGFR1 gene encodes fibroblast growth factor receptor 1 (FGFR1), a pivotal transmembrane receptor tyrosine kinase widely expressed across diverse cell types, including epithelial, mesenchymal, and neuronal lineages, playing fundamental roles in development, angiogenesis, cell proliferation, differentiation, and migration through activation of intracellular signaling cascades like MAPK/ERK, PI3K/AKT, and STAT ^[1]. Aberrant FGFR1 expression or mutations are associated with developmental syndromes and various cancers, driving tumor growth, metastasis, and therapeutic resistance; its expression is tightly regulated by diverse cellular signals ^[2]. A key splice isoform is FGFR1c, predominantly expressed in epithelial cells and characterized by a specific extracellular immunoglobulin-like domain III, conferring high-affinity binding to a subset of FGF ligands crucial for epithelial-mesenchymal interactions during development and adult tissue homeostasis ^[3]. Dysregulation of FGFR1c signaling is implicated in the pathogenesis of cancers such as breast, prostate, and lung carcinomas, contributing to tumor initiation, progression, angiogenesis, and potentially therapy resistance, highlighting the importance of understanding isoform-specific functions for targeted therapeutic interventions ^[3-4]. B6-hFGFR1c mice are humanized models generated by gene editing technology, in which the p.22R to partial intron 2 of the mouse Fgfr1 gene was replaced in situ with p.22R to 376E from the coding sequence of the human FGFR1 gene, p.377I to 823X from the coding sequence of the mouse Fgfr1 gene, and the 3'UTR of the mouse Fgfr1 gene. This model can be used to study the pathological mechanisms and therapeutic methods of cancers, metabolic diseases such as obesity, diabetes, and metabolic-associated steatohepatitis (MASH), as well as the screening and development of FGFR1c-targeted drugs, and preclinical efficacy and safety evaluations.

Glra4 is located on chromosome X of mice. Nuclease Technology was used to design sgRNA; Glra4 knockout mice were obtained by applying high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.

Gnb1l is located on chromosome 16 of mice. SgRNA and ssDNA were designed using Nuclease Technology; Gnb1l conditional knockout mice were obtained by high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.