Transcription factor Isl1 is dispensable for the development of the mouse prosensory region.

In order to identify genes involved in the development of inner ear hair cells, we investigated the role of the transcription factor Islet-class LIM-homeodomain (LIM-HD) 1 (Isl1) in the development of the mouse prosensory region. Isl1 was deleted using the Pax2-Cre system, and deletion of both alleles was verified using cochlea sections. Changes in the number of prosensory region cells were measured to determine the effect of Isl1 on the development of the mouse prosensory region. In order to test whether Isl1 formed a protein complex with Ldb1 and Gata3, co-immunoprecipitation experiments were performed in HEK293 cells using the Flag-tagged LIM-domain of Isl1, HA-tagged LID of Ldb1 and Myc-tagged C-terminal domain of Gata3. The expression of Gata3, Sox2, Jag1 and P27 proteins in the prosensory region were not affected in Isl1-/- prosensory cells. Thus, Isl1 did not form a protein complex with Gata3 through Ldb1 in the Isl1-/- cells. Our results suggest that Isl1 may be dispensable for the development of the mouse prosensory region.