The wound epithelium of regenerating limbs of Pleurodeles waltl and Notophthalmus viridescens: studies with mAbs WE3 and WE4, phalloidin, and DNase 1.

The wound epithelium of regenerating limbs of the American newt, Notophthalmus viridescens (Nv), up-regulates a number of antigens, including those recognized by mAbs WE3 and WE4. In the present study, we show that the WE3 antigen is up-regulated in a similar fashion in the wound epithelium of the European newt, Pleurodeles waltl (Pw). mAb WE3 and WE4 reactivities to secretory/transport body cell types, including integumentary glands, perineurium, endothelium, and conjunctiva, are also similar in these two species of newt. However, mAb WE4 reacts to both the epidermis and wound epithelium in Pw, whereas in Nv, mAb WE4 reacts only to the wound epithelium. Because the WE3 antigen is cytoskeleton-associated and Western blots reveal a 43 kDa species, we compared mAb WE3 reactivity with that of rhodamine-labeled phalloidin, a known actin-binding compound. Phalloidin did not react preferentially to the wound epithelium, conjunctiva, or other cell types strongly reactive to mAb WE3. Pretreatment of sections and tissue extracts with DNAse 1, a protein known to bind to actin, nearly abolished mAb WE3 reactivity in tissue sections and both WE3 and WE4 reactivity in ELISA assays, respectively. The results lead to the hypothesis that the WE3 and WE4 antigens are actin-binding proteins unique to the wound epithelium and other secretory/transport cell types.