Project description:Retinoblastoma gene (Rb1) is required for proper cell cycle exit in the developing mouse inner ear and its deletion in the embryo leads to proliferation of sensory progenitor cells that differentiate into hair cells and supporting cells. In the Pou4f3-Cre:Rb1 flox/flox (Rb1 cKO) inner ear, utricular hair cells differentiate and survive into adulthood whereas differentiation and survival of cochlear hair cells are impaired. To comprehensively survey the pRb pathway in the mammalian inner ear, we performed microarray analysis of Rb1 cKO cochlea and utricle. P6 or 2-month control and Rb1 cKO littermates were euthanized and the inner ear tissues were dissected. Total RNA was extracted from the pooled samples. Technical duplicates of the pooled RNA were used for microarray.
Project description:Retinoblastoma gene (Rb1) is required for proper cell cycle exit in the developing mouse inner ear and its deletion in the embryo leads to proliferation of sensory progenitor cells that differentiate into hair cells and supporting cells. In the Pou4f3-Cre:Rb1 flox/flox (Rb1 cKO) inner ear, utricular hair cells differentiate and survive into adulthood whereas differentiation and survival of cochlear hair cells are impaired. To comprehensively survey the pRb pathway in the mammalian inner ear, we performed microarray analysis of Rb1 cKO cochlea and utricle.
Project description:Hearing and balance are mediated in vertebrates by inner ear mechanosensory hair cells. Hair cell development, maturation and survival require POU4F3, a class IV POU domain transcription factor that is expressed in hair cells shortly after they start to differentiate. Here, we show that POU4F3 has pioneer factor activity, and is necessary to promote chromatin accessibility at approximately half of the distal regulatory elements that appear as hair cells differentiate. Pou4f3 expression in the inner ear is initiated by ATOH1, a bHLH transcription factor that is also necessary for hair cell differentiation and survival. We show that ATOH1 also binds a large number of POU4F3-dependent distal regulatory elements, suggesting a synergistic feed-forward model in which ATOH1 induces POU4F3, which then acts to promote ATOH1-dependent hair cell differentiation.
Project description:To understand the basic biological property of hair cells (HCs) from lower vertebrates, we examined transcriptomes of adult zebrafish HCs. GFP-labeled HCs were isolated from the utricle, saccule, and lagena, the three inner-ear sensory epithelia of a pou4f3 promoter-driven GAP-GFP line of transgenic zebrafish. 2,000 HCs and 2,000 non-sensory cells from the inner ear were individually collected by suction pipet technique. RNA sequencing was performed and the resulting sequences were mapped, analyzed, and compared. Comparisons allow us to identify enriched genes in HCs, which may underlie HC specialization.