Nonsense mutations of the bHLH transcription factor TWIST2 found in Setleis Syndrome patients cause dysregulation of periostin.
Nonsense mutations of the bHLH transcription factor TWIST2 found in Setleis Syndrome patients cause dysregulation of periostin.
复制标题
DOI：
10.1016/j.biocel.2011.07.003
复制
发表时间：
2011-10
影响因子：
4
通讯作者：
Cadilla, Carmen L.
中科院分区：
文献类型：
--
作者：
Franco, Hector L.;Casasnovas, Jose J.;Leon, Ruth G.;Friesel, Robert;Ge, Yongchao;Desnick, Robert J.;Cadilla, Carmen L.
Setleis综合征（OMIM ID: 227260）是一种罕见的常染色体隐性遗传病，其特征是面部发育异常。最近，我们报道了基本螺旋-环-螺旋（bHLH）转录因子TWIST2的两个无义突变（c.486C>T [Q119X]和c.324C>T [Q65X]）导致Setleis综合征。本研究表明，参与结缔组织发育和维持的细胞粘附蛋白——骨膜蛋白在Setleis综合征患者成纤维细胞中下调，而骨膜蛋白对TWIST2水平的调控有积极反应，表明TWIST2是骨膜蛋白的反激活因子。对TWIST2突变体（Q119X）的功能分析表明，它保持了定位细胞核的能力，与普遍存在的bHLH蛋白E12形成同源和异源二聚体，并与dsDNA结合。使用人类骨膜蛋白启动子缺失构建的报告基因分析也显示，TWIST2比Twist1更能特异性地激活该基因，而Q119X突变体没有显著的反激活。染色质免疫沉淀实验表明，野生型TWIST2和Q119X突变体都结合了骨膜蛋白启动子，但只有野生型TWIST2与高水平的组蛋白乙酰化有关，这些组蛋白乙酰化跨越了骨膜蛋白的5 ' -调节区域。综上所述，这些数据表明，在TWIST2的Q119X突变体中缺失的TWIST2的c端结构域负责正确的反激活periostin基因。TWIST2突变形式对骨膜蛋白的不当调控可能有助于解释这些患者中出现的一些软组织异常，因此为Setleis综合征提供了基因型-表型关系。
Setleis Syndrome (OMIM ID: 227260) is a rare autosomal recessive disease characterized by abnormal facial development. Recently, we have reported that two nonsense mutations (c.486C>T [Q119X] and c.324C>T [Q65X]) of the basic helix-loop-helix (bHLH) transcription factor TWIST2 cause Setleis Syndrome. Here we show that periostin, a cell adhesion protein involved in connective tissue development and maintenance, is down-regulated in Setleis Syndrome patient fibroblast cells and that periostin positively responds to manipulations in TWIST2 levels, suggesting that TWIST2 is a transactivator of periostin. Functional analysis of the TWIST2 mutant form (Q119X) revealed that it maintains the ability to localize to the nucleus, forms homo and heterodimers with the ubiquitous bHLH protein E12, and binds to dsDNA. Reporter gene assays using deletion constructs of the human periostin promoter also reveal that TWIST2 can activate this gene more specifically than Twist1, while the Q119X mutant results in no significant transactivation. Chromatin immunoprecipitation assays show that both wild-type TWIST2 and the Q119X mutant bind the periostin promoter, however only wild-type TWIST2 is associated with higher levels of histone acetylation across the 5′-regulatory region of periostin. Taken together, these data suggest that the C-terminal domain of TWIST2, which is missing in the Q119X mutant form of TWIST2, is responsible for proper transactivation of the periostin gene. Improper regulation of periostin by the mutant form of TWIST2 could help explain some of the soft tissue abnormalities seen in these patients therefore providing a genotype-phenotype relationship for Setleis Syndrome.
登录
查看更多内容
影响因子：
16
作者：
Firulli, BA;Howard, MJ;Firulli, AB
通讯作者：
Firulli, AB
影响因子：
4
作者：
Oshima, A;Tanabe, H;Kudo, A
通讯作者：
Kudo, A
影响因子：
4.1
作者：
Lee, MS;Lowe, G;Glackin, CA
通讯作者：
Glackin, CA
影响因子：
3
作者：
Afanador, E;Yokozeki, M;Moriyama, K
通讯作者：
Moriyama, K
影响因子：
3.4
作者：
Puglisi, F.;Puppin, C.;Di Loreto, C.
通讯作者：
Di Loreto, C.