• SEZ6 (Seizure protein 6, also BSRP-C, Brain-specific receptor-like protein C) is a 150 kDa member of the BSRP family of proteins. It is expressed on neurons and exerts an anti branching effect relative to neurite extension. 
• Mature mouse SEZ6 is a 974 amino acid (aa) type I transmembrane glycoprotein. It contains an extracellular domain (ECD) of at least 876 amino acids (aa 18‑893). The ECD shows three CUB domains and five short consensus repeats (SCRs). 
• There are two splice variants for SEZ6. One is soluble, and shows an 18 aa substitution for aa 588‑991, while a second shows a deletion of aa 895‑907 plus a 9 aa substitution for aa 982‑991. Over aa 19‑902, mouse SEZ6 is 91% aa identical to human SEZ6.

Strain specific analysis of SEZ6 mRNA expression in wild-type C57BL/6 mice and B-hSEZ6 mice by RT-PCR. Cerebral cortex RNA were isolated from wild-type C57BL/6 mice (+/+) and homozygous B-hSEZ6 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human SEZ6 primers. Mouse Sez6 mRNA was detectable only in wild-type C57BL/6 mice. Human SEZ6 mRNA was detectable only in homozygous B-hSEZ6 mice but not in wild-type mice. 

Western blot analysis of SEZ6 protein expression in homozygous B-hSEZ6 mice. Various tissue lysates were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hSEZ6 mice (H/H), and then analyzed by western blot with anti-SEZ6 antibody (Abcam, ab314233). 40 μg total proteins were loaded for western blotting analysis. SEZ6 was detected in cerebral cortex, as the antibody is cross-reactive between human and mouse SEZ6. (The arrow above indicates the glycosylated SEZ6 protein, the arrows below indicates the SEZ6 protein 1,2)