Eya1, belonging to a family of phosphatase-transcriptional activators, lacks intrinsic DNA-binding activity. It is crucial for establishing and maintaining nephron progenitor cells (NPCs), and also plays essential roles in progenitor proliferation, cell differentiation and morphogenesis in all three germ layers [1,2]. It interacts with the homeodomain protein SIX1 to form transcriptional activation complexes, which are vital in inner ear development, regulating cell proliferation, survival and induction of sensory and neuronal differentiation programs [3]. Eya1 is also involved in the Sonic hedgehog (Shh) signaling pathway, which is critical in development and oncogenesis [8].

In NPCs, Eya1 can modify chromatin structure by interacting with chromatin-remodeling factors and specialized DNA-binding proteins, forming regulatory complexes that can regulate transcription both positively and negatively, thus maintaining the cellular state of NPCs [1]. Mutations in Eya1 are associated with Branchio-Oto-Renal (BOR) syndrome, an autosomal dominant disorder characterized by second branchial arch anomalies, hearing impairment, and renal malformations [5,6,7]. In hepatocellular carcinoma, EYA1 promotes cell migration and tumor metastasis by activating FNDC3B [4]. In the hindbrain, Eya1 promotes Shh signaling, being critical for Shh-dependent hindbrain growth and development, and also drives the growth of medulloblastoma, a Shh-dependent hindbrain tumor [8]. In cerebellar development, Eya1 mediates Shh-driven symmetric cell division of cerebellar granule cell precursors by inactivating aPKC, which is a direct target of Eya1 activity [9].

In conclusion, Eya1 is a multifunctional gene involved in various biological processes such as organ development, cell division, and disease-related processes like tumor metastasis. Its study, especially through gene knockout or conditional knockout mouse models, has revealed its importance in understanding the mechanisms of BOR syndrome, hindbrain development and tumorigenesis, providing insights into potential therapeutic strategies for related diseases.

References:

1. Li, Jun, Cheng, Chunming, Xu, Jinshu, Wang, Rong, Xu, Pin-Xian. . The transcriptional coactivator Eya1 exerts transcriptional repressive activity by interacting with REST corepressors and REST-binding sequences to maintain nephron progenitor identity. In Nucleic acids research, 50, 10343-10359. doi:10.1093/nar/gkac760. https://pubmed.ncbi.nlm.nih.gov/36130284/

2. Almasoudi, Suad Hamdan, Schlosser, Gerhard. 2021. Eya1 protein distribution during embryonic development of Xenopus laevis. In Gene expression patterns : GEP, 42, 119213. doi:10.1016/j.gep.2021.119213. https://pubmed.ncbi.nlm.nih.gov/34536585/

3. Wong, Elaine Y M, Ahmed, Mohi, Xu, Pin-Xian. 2012. EYA1-SIX1 complex in neurosensory cell fate induction in the mammalian inner ear. In Hearing research, 297, 13-9. doi:10.1016/j.heares.2012.09.009. https://pubmed.ncbi.nlm.nih.gov/23104013/

4. Kong, Deguang, Ma, Weijie, Zhang, Dan, Liu, Zhisu, Wu, Gaosong. 2019. EYA1 promotes cell migration and tumor metastasis in hepatocellular carcinoma. In American journal of translational research, 11, 2328-2338. doi:. https://pubmed.ncbi.nlm.nih.gov/31105839/

5. Castiglione, Alessandro, Melchionda, Salvatore, Carella, Massimo, Manara, Renzo, Martini, Alessandro. 2014. EYA1-related disorders: two clinical cases and a literature review. In International journal of pediatric otorhinolaryngology, 78, 1201-10. doi:10.1016/j.ijporl.2014.03.032. https://pubmed.ncbi.nlm.nih.gov/24803398/

6. Tian, Yuan, Lv, Yuexia, Wang, Handuo, Cui, Xueyin, Liu, Ling. 2024. Prenatal Phenotypic Analysis of Branchio-Oto-Renal Spectrum Disorder Attributable to EYA1 Gene Pathogenic Variants and Systematic Literature Review. In Prenatal diagnosis, 44, 1509-1517. doi:10.1002/pd.6673. https://pubmed.ncbi.nlm.nih.gov/39394648/

7. Klingbeil, Kyle D, Greenland, Christopher M, Arslan, Selcuk, Bademci, Guney, Tekin, Mustafa. 2017. Novel EYA1 variants causing Branchio-oto-renal syndrome. In International journal of pediatric otorhinolaryngology, 98, 59-63. doi:10.1016/j.ijporl.2017.04.037. https://pubmed.ncbi.nlm.nih.gov/28583505/

8. Eisner, Adriana, Pazyra-Murphy, Maria F, Durresi, Ershela, Greenberg, Michael E, Segal, Rosalind A. 2015. The Eya1 phosphatase promotes Shh signaling during hindbrain development and oncogenesis. In Developmental cell, 33, 22-35. doi:10.1016/j.devcel.2015.01.033. https://pubmed.ncbi.nlm.nih.gov/25816987/

9. Merk, Daniel J, Zhou, Pengcheng, Cohen, Samuel M, Harwell, Corey C, Segal, Rosalind A. 2021. The Eya1 Phosphatase Mediates Shh-Driven Symmetric Cell Division of Cerebellar Granule Cell Precursors. In Developmental neuroscience, 42, 170-186. doi:10.1159/000512976. https://pubmed.ncbi.nlm.nih.gov/33472197/