The regulation of gene expression in hair cells

Abstract

No genes have been discovered for which expression is limited only to inner ear hair cells. This is hardly surprising, since the number of mammalian genes is estimated to be 20–25,000, and each gene typically performs many tasks in various locations. Many genes are expressed in inner ear sensory cells and not in other cells of the labyrinth. However, these genes are also expressed in other locations, often in other sensory or neuronal cell types. How gene transcription is directed specifically to hair cells is unclear. Key transcription factors that act during development can specify cell phenotypes, and the hair cell is no exception. The transcription factor ATOH1 is well known for its ability to transform nonsensory cells of the developing inner ear into hair cells. And yet, ATOH1 also specifies different sensory cells at other locations, neuronal phenotypes in the brain, and epithelial cells in the gut. How it specifies hair cells in the inner ear, but alternate cell types in other locations, is not known. Studies of regulatory DNA and transcription factors are revealing mechanisms that direct gene expression to hair cells, and that determine the hair cell identity. The purpose of this review is to summarize what is known about such gene regulation in this key auditory and vestibular cell type.

Genes Involved in the Development and Physiology of Both the Peripheral and Central Auditory Systems

“…The present review brings to light the limited existing knowledge of GRNs, even in the hair cells. Efforts to characterize them at the transcriptomic, posttranscriptomic, and epigenetic levels, have focused on a limited number of genes, including Atoh1, Pou4f3, and a few hair cell genes, such as Myo7a (reviewed in (Ryan et al 2015)).…”

Preservation of Cells of the Organ of Corti and Innervating Dendritic Processes Following Cochlear Implantation in the Human: An Immunohistochemical Study

“…Immunostaining of the hair cells was accomplished using an antibody to myosin-VIIa (Proteus Biosciences Inc., Ramona, CA) at a dilution of 1:200. Myosin-VIIa is expressed in inner and outer hair cells throughout life (18).…”

Focal Degeneration of Vestibular Neuroepithelium in the Cristae Ampullares of Three Human Subjects

“…Labeling of the vestibular sensory cells was done with a rabbit polyclonal primary antibody made against myosin VIIa (ProteusBiosciences Inc., Ramona, CA) at a dilution of 1:100. Myosin VIIa is expressed in vestibular hair cells of both mice and humans (8, 9).…”