Description

• Epcam, also known as CD326, belongs to the GA733 protein family. It is a type I transmembrane glycoprotein and a homotypic Ca2+-independent cell adhesion molecule. It is expressed at low levels in the basal membrane of various normal epithelial cells (with the highest expression in the colon) but is widely expressed on the membranes of cancer cells, particularly in squamous cell carcinoma and adenocarcinoma.
• Rat Epcam mRNA was only detectable in wild-type SD rats. Human EPCAM mRNA was exclusively detectable in homozygous B-hEPCAM rats but not in wild-type SD rats.
• Rat EPCAM was detectable in lung, kidney, small intestine and large intestine of wild-type SD rats. Human EPCAM was detectable in lung, kidney, small intestine, large intestine and skin of B-hEPCAM rats.
• B-hEPCAM rats can be used for toxicology and drug safety evaluation.

Targeting strategy

Gene targeting strategy for B-hEPCAM rats.

The exons 2-7 of rat Epcam gene that encode extracellular domain and part of transmembrane domain were replaced by human counterparts in B-hEPCAM rats. The genomic region of rat Epcam gene that encode signal peptide, cytoplasmic portion and part of transmembrane domain were retained. The promoter, 5’UTR and 3’UTR region of the rat gene were also retained. The chimeric EPCAM expression was driven by endogenous rat Epcam promoter, while rat Epcam gene transcription and translation will be disrupted.

mRNA expression analysis

Strain specific analysis of EPCAM mRNA expression in wild-type SD rats and B-hEPCAM rats by RT-PCR. Lung RNA were isolated from wild-type SD rats (+/+) and homozygous B-hEPCAM rats (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with rat or human EPCAM primers. Rat Epcam mRNA was only detectable in wild-type SD rats. Human EPCAM mRNA was exclusively detectable in homozygous B-hEPCAM rats but not in wild-type SD rats.

Protein expression analysis

Immunohistochemical (IHC) analysis of EPCAM expression in homozygous B-hEPCAM rats. The heart, liver, spleen, lung, kidney, small intestine, large intestine and skin were collected from wild-type rats and homozygous B-hEPCAM rats (H/H), analyzed by IHC with anti-rat EPCAM (abcam, ab213501) and anti-human EPCAM (abcam, ab223582) respectively. Rat EPCAM was detectable in wild-type rats, and human EPCAM was detectable in homozygous B-hEPCAM rats. The arrow indicates tissue cells with positive EPCAM staining (brown).