Cloning and characterization of porcine aquaporin 1 water channel expressed extensively in gastrointestinal system

Figure 5 Functional properties of pAQP1 in erythrocytes and stably transfected CHO cells. A: Osmotic water permeability of pig, human and mouse erythrocytes measured by stopped-flow light scattering from the time course of erythrocyte volume in response to a 100 mmol/L inwardly directed sucrose gradient in the absence (left panel) and presence (right panel) of 0.3 mmol/L HgCl₂; B: Summary of osmotic water permeability coefficient (Pf) for erythrocytes from pig, human and mouse measured in A (mean ± SE, n = 4); C: Osmotic water permeability of CHO cells stably transfected with pAQP1 cDNA measured by YFP-based fluorescence assay. Water permeability of CHO cells was expressed as half time (t_1/2) needed from water injection to the point when the cytoplasmic fluorescence reached the maximum. t_1/2 of pAQP1 transfected CHO cells in the absence and presence of 0.1 mmol/L HgCl₂ was 1.2 s and 4.6 s separately. t_1/2 > 20 s in mock-transfected CHO cells; D: Immunoblot of erythrocytes and transfected CHO cells. Lanes 1 - 4: erythrocytes from AQP1-/- mice, AQP1 +/+ mice, pigs and human beings. Lane 5: CHO cells stably transfected with pAQP1 cDNA.