Mouse Models with Spatially Limited Pendrin Expression
Slc26a4 transcription is controlled by various regulatory elements in the promoter region of Slc26a4 that allow the expression to be cell-specific and responsive to specific situations (Yang et al. 2007; Adler et al. 2008; Rozenfeld et al. 2012; Vanoni et al. 2013). Notably, expression in mitochondria-rich cells of the endolymphatic sac of the inner ear is driven by the transcription factor FOXI1, whereas expression in the cochlea and the vestibular labyrinth is driven by other regulators (Yang et al. 2007). FOXI1 in mitochondria-rich cells of the endolymphatic sac drives not only the expression of pendrin but also the expression of ATP6V1B1, a subunit of the H+ ATPase that is expressed in the inner ear only in these cells (Vidarsson et al. 2009). FOXI1 and ATP6V1B1 have therefore been used to generate mouse models that exclude the expression of pendrin from the endolymphatic sac or that limit the expression of pendrin in the inner ear to the endolymphatic sac.