<scp><i>Eya2</i></scp> expression during mouse embryonic development revealed by <scp><i>Eya2</i><sup><i>lacZ</i></sup></scp> knockin reporter and homozygous mice show mild hearing loss
Ting Zhang, Jin Xu, Pin‐Xian Xu
Abstract
Abstract Background Eya2 expression during mouse development has been studied by in situ hybridization and it has been shown to be involved skeletal muscle development and limb formation. Here, we generated Eya2 knockout ( Eya2 − ) and a lacZ knockin reporter ( Eya2 lacZ ) mice and performed a detailed expression analysis for Eya2 lacZ at different developmental stages to trace Eya2 lacZ ‐positive cells in Eya2 ‐null mice. We describe that Eya2 is not only expressed in cranial sensory and dorsal root ganglia, retina and olfactory epithelium, and somites as previously reported, but also Eya2 is specifically detected in other organs during mouse development. Results We found that Eya2 is expressed in ocular and trochlear motor neurons. In the inner ear, Eya2 lacZ is specifically expressed in differentiating hair cells in both vestibular and cochlear sensory epithelia of the inner ear and Eya2 −/− or Eya2 lacZ/lacZ mice displayed mild hearing loss. Furthermore, we detected Eya2 expression during both salivary gland and thymus development and Eya2 ‐null mice had a smaller thymus. Conclusions As Eya2 is coexpressed with other members of the Eya family genes, these results together highlight that Eya2 as a potential regulator may act synergistically with other Eya genes to regulate the differentiation of the inner ear sensory hair cells and the formation of the salivary gland and thymus.