• CD171, also known as L1CAM or L1, is a transmembrane glycoprotein. It is a 200-220 kDa neuronal cell adhesion molecule and a member of the L1 protein family belonging to the immunoglobulin superfamily.
• This cell adhesion molecule plays an important role in nervous system development, including neuron-neuron adhesion, signal transduction, axon guidance, cell migration and differentiation. CD171 also has a strong implication in treatment-resistant cancers. Mutations in the gene cause three X-linked neurological syndromes known by the acronym CRASH (corpus callosum hypoplasia, retardation, aphasia, spastic paraplegia and hydrocephalus). Alternative splicing of a neuron-specific exon is thought to be functionally relevant.

Gene targeting strategy for B-hL1CAM mice. The exons 1-29 of mouse L1cam gene that encode the whole molecule (ATG to STOP codon), including 5’UTR and 3’UTR are replaced by human counterparts in B-hL1CAM mice. The human L1CAM expression is driven by endogenous human L1CAM promoter, while mouse L1cam gene transcription and translation will be disrupted. 

Strain specific L1CAM expression analysis in homozygous B-hL1CAM mice by flow cytometry. Brain were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hL1CAM mice (H/H), and analyzed by flow cytometry with species-specific anti-CD171/L1CAM antibody (R&D, FAB5674P; Invitrogen, 17-1719-41). mCD171/L1CAM was exclusively detectable in wild-type C57BL/6 mice, hCD171/L1CAM was exclusively detectable in homozygous B-hL1CAM mice.