Identification of direct downstream targets of Dlx5 during early inner ear development.
Identification of direct downstream targets of Dlx5 during early inner ear development.
复制标题
DOI：
10.1093/hmg/ddq567
复制
发表时间：
2011-04
影响因子：
3.5
通讯作者：
Samin A Sajan;J. Rubenstein;M. Warchol;M. Lovett
中科院分区：
文献类型：
--
作者：
Samin A Sajan;J. Rubenstein;M. Warchol;M. Lovett
Dlx5 是一种同源框转录因子，在许多器官系统的发育中发挥着关键作用。它是与感音神经性听力损失相关的人类分手/分脚 1 型畸形的候选基因。其增强子之一的缺失与人类颅面缺陷/听力损失有关，也与自闭症有关。然而，人们对Dlx5如何发挥其调节作用知之甚少。我们通过对来自胚胎阶段 E10 和 E10.5 的野生型和 Dlx5 无效耳囊泡进行基因表达谱分析，确定了小鼠内耳中 Dlx5 的直接靶点。 400 个基因有差异表达。我们检查了这些基因启动子区域的基因组 DNA 序列，以了解 (i) 先前描述的 Dlx5 结合位点，(ii) 具有由两个或多个基因共享的规范同源域元件的新型 12 bp 长基序，以及 (iii) 这些基序在人类直向同源物的启动子中 100% 保守。 40 个基因通过了这些过滤器，其中 12 个在耳囊中与 Dlx5 重叠的域中表达。使用 Dlx5 抗体进行的染色质免疫沉淀证实，在过表达 Dlx5 的细胞系中，Dlx5 与其中 7 个启动子（Atbf1、Bmper、Large、Lrrtm1、Msx1、Ebf1 和 Lhx1）直接结合。 Bmper 和 Lrrtm1 在此细胞系中上调，进一步支持它们被鉴定为内耳和其他器官中 Dlx5 的靶标。这些直接靶标支持早期内耳中 Bmp 信号传导位于 Dlx5 下游的模型，并为 Dlx5 调控级联如何启动提供了新的见解。
Dlx5, a homeobox transcription factor, plays a key role in the development of many organ systems. It is a candidate gene for human split-hand/split-foot type 1 malformation associated with sensorineural hearing loss. A deletion of one of its enhancers has been implicated in human craniofacial defects/hearing loss and it has also been associated with autism. However, little is known of how Dlx5 exerts its regulatory effects. We identified direct targets of Dlx5 in the mouse inner ear by gene expression profiling wild-type and Dlx5 null otic vesicles from embryonic stages E10 and E10.5. Four hundred genes were differentially expressed. We examined the genomic DNA sequences in the promoter regions of these genes for (i) previously described Dlx5 binding sites, (ii) novel 12 bp long motifs with a canonical homeodomain element shared by two or more genes and (iii) 100% conservation of these motifs in promoters of human orthologs. Forty genes passed these filters, 12 of which are expressed in the otic vesicle in domains that overlap with Dlx5. Chromatin immunoprecipitation using a Dlx5 antibody confirmed direct binding of Dlx5 to promoters of seven of these (Atbf1, Bmper, Large, Lrrtm1, Msx1, Ebf1 and Lhx1) in a cell line over-expressing Dlx5. Bmper and Lrrtm1 were up-regulated in this cell line, further supporting their identification as targets of Dlx5 in the inner ear and potentially in other organs. These direct targets support a model in which Bmp signaling is downstream of Dlx5 in the early inner ear and provide new insights into how the Dlx5 regulatory cascade is initiated.