A Sox10rtTA/+ Mouse Line Allows for Inducible Gene Expression in the Auditory and Balance Organs of the Inner Ear

Abstract

Genetic mouse models provide invaluable tools for discerning gene function in vivo. Tetracycline-inducible systems (Tet-On/Off) provide temporal and cell-type specific control of gene expression, offering an alternative or even complementary approach to existing Cre/LoxP systems. Here we characterized a Sox10(rtTA/+) knock-in mouse line which demonstrates inducible reverse tetracycline trans-activator (rtTA) activity and Tet-On transgene expression in the inner ear following induction with the tetracycline derivative doxycycline (Dox). These Sox10(rtTA/+) mice do not exhibit any readily observable developmental or hearing phenotypes, and actively drive Tet-On transgene expression in Sox10 expressing cells in the inner ear. Sox10(rtTA/+) activity was revealed by multiple Tet-On reporters to be nearly ubiquitous throughout the membranous labyrinth of the developing inner ear, and notably absent from hair cells, tympanic border cells, and ganglion neurons following postnatal Dox inductions. Interestingly, Dox-induced Sox10(rtTA/+) activity declined with induction age, where Tet-On reporters became uninducible in adult cochlear epithelium. Co-administration of the loop diuretic furosemide was able to rescue Dox-induced reporter expression, though this method also caused significant cochlear hair cell loss. Surprisingly, Sox10(rtTA/+) driven reporter expression in the cochlea persists for at least 54 days after cessation of neonatal induction, presumably due to the persistence of Dox within inner ear tissues. These findings highlight the utility of the Sox10(rtTA/+) mouse line as a powerful tool for functional genetic studies of the auditory and balance organs in vivo, but also reveal some important considerations that must be adequately controlled for in future studies that rely upon Tet-On/Off systems.

Single Cell and Single Nucleus RNA-Seq Reveal Cellular Heterogeneity and Homeostatic Regulatory Networks in Adult Mouse Stria Vascularis

“…These data identify the loss of these genes in the SV as principal drivers of hearing loss in digenic Gjb2 and Gjb6 mutations. Use of SV promoters that may be capable of targeting multiple SV cell types including Mitf or Sox10 could be utilized in future therapeutic attempts ( Figure 10) (Hao et al, 2014;Walters and Zuo, 2015).…”

ERBB2 is a Key Mediator in Hearing Restoration in Noise-Deafened Young Adult Mice

“…1A). This protocol has been shown to be effective in driving Tet-ON promoters in cochlear supporting cells (42). Effects of this intervention on ABR thresholds were assessed at 30, 60 and 90 DPN (Fig.…”

Single cell and single nucleus RNA-Seq reveal cellular heterogeneity and homeostatic regulatory networks in adult mouse stria vascularis

“…Use of SV promoters that may be capable of targeting multiple SV cell types including Mitf or Sox10 could be utilized in future therapeutic attempts ( Fig. 10) (Hao et al, 2014;Walters & Zuo, 2015).…”