Division of Medical Biochemistry, Tohoku Medical Pharmaceutical University, Sendai, Japan
Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan.
Mol Cell Biol. 2018 Oct 15;38(21). doi: 10.1128/MCB.00302-18. Print 2018 Nov 1.
Transcription factor GATA3 plays vital roles in inner ear development, while regulatory mechanisms controlling its inner ear-specific expression are undefined. We demonstrate that a -regulatory element lying 571 kb 3' to the gene directs inner ear-specific expression, which we refer to as the otic vesicle enhancer (OVE). In transgenic murine embryos, a 1.5-kb OVE-directed reporter (Tg) exhibited robust expression specifically in the otic vesicle (OV), an inner ear primordial tissue, and its derivative semicircular canal. To further define the regulatory activity of this OVE, we generated Cre transgenic mice in which Cre expression was directed by a 246-bp core sequence within the OVE element (Tg). Tg successfully marked the OV-derived inner ear tissues, including cochlea, semicircular canal and spiral ganglion, when crossed with ROSA26 reporter mice. Furthermore, conditionally mutant mice, when crossed with the Tg, showed hypoplasia throughout the inner ear tissues. These results demonstrate that OVE has a sufficient regulatory activity to direct expression specifically in the otic vesicle and semicircular canal and that expression driven by the OVE is crucial for normal inner ear development.
转录因子 GATA3 在内耳发育中起着至关重要的作用，然而，控制其内耳特异性表达的调节机制尚不清楚。我们证明，位于基因 3'端 571 kb 处的一个 -调节元件指导内耳特异性表达，我们称之为 耳泡增强子 (OVE)。在转基因鼠胚胎中，一个 1.5 kb 的 OVE 指导的 报告基因 (Tg) 在耳泡 (OV)，即内耳原基组织及其衍生的半规管中特异性表达。为了进一步确定该 OVE 的调节活性，我们生成了 Cre 转基因小鼠，其中 Cre 表达由 OVE 元件内的 246 bp 核心序列指导 (Tg)。当与 ROSA26 报告小鼠杂交时，Tg 成功标记了由 OV 衍生的内耳组织，包括耳蜗、半规管和螺旋神经节。此外，当与 Tg 杂交时，条件性突变小鼠的内耳组织出现发育不全。这些结果表明，OVE 具有足够的调节活性，可以特异性地指导 基因在耳泡和半规管中的表达，并且由 OVE 驱动的 表达对于正常内耳发育至关重要。
