Figure 3: Expression of the Na+-ATPase mRNA in MDCK cells by RT-PCR. Expression of the homologous canine ATNA, corresponding to Na+-ATPase mRNA, was determined in MDCK cells by specific RT-PCR as described in the methods. PCR products were analyzed by electrophoresis in 2% agarose. The expected atna DNA band of 266 bp was amplified from 1 μg of MDCK total RNA (line 2). DEPC-treated water was used as negative control (line 3). The 50 bp DNA ladder from Invitrogen was used as weight marker (lane 1).