GEOapplication/xmlftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE300nnn/GSE300215/primaryOK200TranscriptomicsMus musculusExpression profiling by high throughput sequencinghttps://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE300215GEOGSEfalseCASZ1 regulates the rate at which outer hair cells mature and is required for hearingThe transcriptional activator ATOH1 is a master regulator of the development of mechanosensory hair-cells (HCs) in the ear. We report that the ATOH1 target gene Casz1 encodes a transcription factor that regulates the rate of outer HC (OHC) maturation by gene repression. Genetic deletion of Casz1 during (but not after) development of the mouse cochlea caused: hearing loss; abnormal organization of mechanosensory stereocilium bundles and abnormally low F-actin density in cuticular plates in OHCs; progressive loss of OHCs; and mild morphological alterations in inner HCs. RNA sequencing revealed that Casz1 deletion delayed downregulation of genes expressed in immature OHCs, including the actin regulator-encoding gene Coro2a, and accelerated upregulation of genes expressed in mature OHCs. Coro2a knockdown restored the density of cuticular plate F-actin in Casz1 mutant OHCs. Our data indicate that CASZ1 regulates transcriptional and morphological maturation of OHCs, and that CASZ1 in maturing HCs is necessary for hearing.2026/06/22GSE300215GSM9055891GSM9055892GSM9055893GSM9055894GSM9055895GSM9055886GSM9055887GSM9055888GSM9055889GSM905589030172300215Mus musculus[40631138]