Background: The PLXNA1 gene encodes Plexin A1 (neuropilin-plexin A1), a type I transmembrane protein that serves as a receptor for semaphorin-3A and -6D. This protein plays crucial roles in neuronal axon guidance, cytoskeletal organization, invasive growth, and cell migration.Elevated PLXNA1 expression is strongly associated with the pathogenesis and progression of various malignancies, including prostate cancer, gastric cancer, and esophageal squamous cell carcinoma. Genetic knockout of PLXNA1 significantly suppresses tumor growth in mouse models. Consequently, PLXNA1 inhibitors represent promising therapeutic candidates for cancer treatment.

Targeting strategy: The exons 2-20 of mouse Plxna1 gene that encode signal peptide and extracellular domain are replaced by human counterparts in B-hPLXNA1 mice. The genomic region of mouse Plxna1 gene that encodes cytoplasmic portion and transmembrane domain is retained. The promoter, 5’UTR and 3’UTR region of the mouse gene are also retained. The chimeric PLXNA1 expression is driven by endogenous mouse Plxna1 promoter, while mouse Plxna1 gene transcription and translation will be disrupted.

Validation: Human PLXNA1 protein was detectable in homozygous B-hPLXNA1 mice. Mouse Plxna1 mRNA was exclusively detectable in C57BL/6JNifdc. Human PLXNA1 mRNA was exclusively detectable in homozygous B-hPLXNA1 mice.

Application：Applicable for pharmacodynamic and safety assessment of oncology drug candidates.

Gene targeting strategy for B-hPLXNA1 mice. The exons 2-20 of mouse Plxna1 gene that encode signal peptide and extracellular domain are replaced by human counterparts in B-hPLXNA1 mice. The genomic region of mouse Plxna1 gene that encodes cytoplasmic portion and transmembrane domain is retained. The promoter, 5’UTR and 3’UTR region of the mouse gene are also retained. The chimeric PLXNA1 expression is driven by endogenous mouse Plxna1 promoter, while mouse Plxna1 gene transcription and translation will be disrupted.

Western blot analysis of PLXNA1 protein expression in homozygous B-hPLXNA1 mice. Various tissue lysates were collected from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hPLXNA1 mice (H/H) (male, 6-week-old), and then analyzed by western blot with anti-PLXNA1 antibody (R&D, AF4309). 40 μg total proteins were loaded for western blotting analysis. PLXNA1 was detectable in testis, lung, brain, kidney and spleen of B-hPLXNA1 mice. This antibody is cross-recognized by human and mouse PLXNA1.

Strain specific analysis of PLXNA1 mRNA expression in wild-type C57BL/6JNifdc and B-hPLXNA1 mice by RT-PCR. Brain RNA were isolated from wild-type C57BL/6JNifdc (+/+) and homozygous B-hPLXNA1 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse and human PLXNA1 primers. Mouse Plxna1 mRNA was exclusively detectable in C57BL/6JNifdc. Human PLXNA1 mRNA was exclusively detectable in homozygous B-hPLXNA1 mice.