• Tetraspanin-8 (TSPAN8), also known as TM4SF3 and human tumor-associated antigen CO-0029, is a member of the transmembrane 4 superfamily. It is a cell surface 27‑34 kDa glycoprotein with 4 transmembrane segments.
• TSPAN8 is expressed in the gastrointestinal tract, including the esophagus, stomach, small and large intestines, and some reproductive organs such as the ovary and testis.
• TSPAN8 would appear to remove Integrins from the cell surface, facilitating cell motility which, in the case of tumor cells, results in metastasis.

Gene targeting strategy for B-hTSPAN8 mice. The entire encoding reigon of mouse Tspan8 gene are replaced by human counterparts in B-hTSPAN8 mice. The promoter, 5’UTR and 3’UTR region of the mouse gene are retained. The human TSPAN8 expression is driven by endogenous mouse TSPAN8 promoter, while mouse TSPAN8 gene transcription and translation will be disrupted.

Western blot analysis of TSPAN8 protein expression in homozygous B-hTSPAN8 mice. Various tissue lysates were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hTSPAN8 mice (H/H), and then analyzed by western blot with anti-TSPAN8 antibody (abcam, ab70007). 40 μg total proteins were loaded for western blotting analysis. hTSPAN8 was detected in stomach, small intestine, colon, kidney and brain. HCT116 cell is positive control. KO tissues are negative control.

Strain specific analysis of TSPAN8 mRNA expression in wild-type C57BL/6 mice and B-hTSPAN8 mice by RT-PCR. Small intestine RNA were isolated from wild-type C57BL/6 mice (+/+) and homozygous B-hTSPAN8 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human TSPAN8 primers. Mouse Tspan8 mRNA were detectable only in wild-type C57BL/6 mice. Human TSPAN8 mRNA was detectable only in homozygous B-hTSPAN8 mice but not in wild-type mice.