Figure 2.

Immunoblot of human and mouse WRN proteins. Whole cell extracts of the indicated cell lines were prepared, and 10 μg of each was analyzed by Western blotting. (A) Immunoblot of 8% polyacrylamide gel, using anti-WRN antibody. Anti-human WRN recognizes a single protein of apparent mobility corresponding to 170 kDa in fibroblast cell line WI38. In a WRN mutant fibroblast cell line, AG0780, no reactive protein is seen. A single protein of slightly increased mobility is seen in an extract prepared from mouse 3T3 cells, in agreement with the previous identification of a single, highly conserved WRN homologue in mouse (38). (B) Immunoblot of a 7.5% polyacrylamide gel, using anti-mWRN antibody. Anti-mWRN recognizes a single protein of apparent mobility corresponding to 165 kDa in normal mouse ear fibroblasts (+/+). No cross-reacting protein is seen in ear fibroblasts prepared from a mouse in which mWRN has been disrupted (−/−).