SPIB is a potential transcription factor capable of influencing pH-regulated AQP1 expression. a Putative SPIB binding site in the region between − 2300 to − 2200 bp upstream of AQP1. b Firefly luciferase activity normalized to Renilla luciferase activity in HEK-293T cells co-transfected with luciferase reporters with the wild-type or mutant AQP1 promoter after treatment at pH 7 or 8. c Chromatin immunoprecipitation (ChIP) in HEK293T cells, followed by real-time PCR amplification of the binding site within the AQP1 promoter region. d ChIP assays for the binding site in the AQP1 promoter were performed in HEK293T cells under different pH conditions. The data represent the mean ± SEM. ns no statistical significance; ***P
{}