Sonic hedgehog signaling directly targets Hyaluronic Acid Synthase 2, an essential regulator of phalangeal joint patterning.
Sonic hedgehog signaling directly targets Hyaluronic Acid Synthase 2, an essential regulator of phalangeal joint patterning.
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DOI：
10.1016/j.ydbio.2012.12.018
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发表时间：
2013-03-15
影响因子：
2.7
通讯作者：
Chiang, Chin
中科院分区：
文献类型：
--
作者：
Liu, Jiang;Li, Qiang;Kuehn, Michael R.;Ying Litingtung;Vokes, Steven A.;Chiang, Chin
由Gli转录因子家族介导的Sonic hedgehog （Shh）信号在肢体的生长和模式形成中起着重要作用。通过对早期肢体芽转录组的分析，我们发现了一个后向富集的基因——透明质酸合成酶2 (Hyaluronic Acid Synthase 2, Has2)，它编码透明质酸（HA）合成的关键酶，是小鼠早期肢体发育过程中Gli转录调控的直接靶点。在Shh null中，肢体芽中的Has2表达缺失，而在Gli3突变体中，Has2在肢体芽前表达扩增。我们发现了一个约3kb的Has2启动子片段，其中包含两个强gli结合的一致序列，在基于细胞的实验中，任何一个位点的突变都取消了Gli1激活Has2启动子的能力。此外，该启动子片段足以指导后肢间质中报告基因的表达。来自肢体芽的DNA-Gli3蛋白复合物的染色质免疫沉淀表明，Gli3与Has2启动子区域强烈结合，表明Has2是Shh信号通路的直接转录靶点。我们还发现，Has2条件突变体（Has2cko）后肢表现出指骨关节纵向移位和软骨形成受损的手指特异性模式缺陷。Has2cko肢间质缩聚能力较弱，硫酸软骨素蛋白聚糖（CSPGs）、聚集蛋白和连接蛋白分布错位。Has2cko肢体表型与软骨素硫酸化缺陷突变体惊人地相似，表明HA对CSPG功能的发育有严格的控制。总之，我们的研究确定了Has2是关节模式和软骨形成所需的Shh信号的一个新的下游靶点。
Sonic hedgehog (Shh) signal, mediated by the Gli family of transcription factors, plays an essential role in the growth and patterning of the limb. Through analysis of the early limb bud transcriptome, we identified a posteriorly-enriched gene, Hyaluronic Acid Synthase 2 (Has2), which encodes a key enzyme for the synthesis of hyaluronan (HA), as a direct target of Gli transcriptional regulation during early mouse limb development. Has2 expression in the limb bud is lost in Shh null and expanded anteriorly in Gli3 mutants. We identified an ~3 kb Has2 promoter fragment that contains two strong Gli-binding consensus sequences, and mutation of either site abrogated the ability of Gli1 to activate Has2 promoter in a cell-based assay. Additionally, this promoter fragment is sufficient to direct expression of a reporter gene in the posterior limb mesenchyme. Chromatin immunoprecipitation of DNA-Gli3 protein complexes from limb buds indicated that Gli3 strongly binds to the Has2 promoter region, suggesting that Has2 is a direct transcriptional target of the Shh signaling pathway. We also showed that Has2 conditional mutant (Has2cko) hindlimbs display digit-specific patterning defects with longitudinally shifted phalangeal joints and impaired chondrogenesis. Has2cko limbs show less capacity for mesenchymal condensation with mislocalized distributions of chondroitin sulfate proteoglycans (CSPGs), aggrecan and link protein. Has2cko limb phenotype displays striking resemblance to mutants with defective chondroitin sulfation suggesting tight developmental control of HA on CSPG function. Together, our study identifies Has2 as a novel downstream target of Shh signaling required for joint patterning and chondrogenesis.
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影响因子：
33.6
作者：
Jiang D;Liang J;Noble PW
通讯作者：
Noble PW
影响因子：
64.5
作者：
Hallikas, O;Palin, K;Taipale, J
通讯作者：
Taipale, J
影响因子：
6
作者：
Bharadwaj, Alamelu G.;Kovar, Joy L.;Simpson, Melanie A.
通讯作者：
Simpson, Melanie A.
影响因子：
2.7
作者：
Chiang, C;Litingtung, Y;Fallon, JF
通讯作者：
Fallon, JF
影响因子：
5.3
作者：
KINZLER, KW;VOGELSTEIN, B
通讯作者：
VOGELSTEIN, B