Expression of truncated PITX3 in the developing lens leads to microphthalmia and aphakia in mice.
Expression of truncated PITX3 in the developing lens leads to microphthalmia and aphakia in mice.
复制标题
DOI：
10.1371/journal.pone.0111432
复制
发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Kikkawa Y
中科院分区：
文献类型：
--
作者：
Wada K;Matsushima Y;Tada T;Hasegawa S;Obara Y;Yoshizawa Y;Takahashi G;Hiai H;Shimanuki M;Suzuki S;Saitou J;Yamamoto N;Ichikawa M;Watanabe K;Kikkawa Y
小眼症是一种严重的眼部疾病，这种情况通常是由参与眼睛发育的转录因子突变引起的。携带这些转录因子突变的小鼠将成为确定发育性眼病潜在机制的有用工具。我们在日本野生自交系KOR1/Stm中发现了一个新的自发隐性小眼小鼠突变体。纯合子突变小鼠的组织学特征是晶状体中缺乏晶状体蛋白，这种情况称为无晶状体。通过定位克隆，我们在编码配对样同源结构域转录因子3基因（Pitx3）同源结构域的基因组区域外发现了无义突变c.444C>A，该突变是导致小眼和无眼的突变。我们利用RT-PCR检测了突变小鼠胚胎期Pitx3 mRNA的表达，发现其表达水平高于野生型小鼠。通过免疫组织化学分析，在小眼突变体的蛋白水平上也证实了发育阶段晶状体中Pitx3的过表达。虽然在突变体中没有观察到晶状体纤维分化，但在突变体晶状体的晶状体囊泡中观察到强烈的PITX3蛋白信号。因此，我们推测由于无义突变而缺乏c端（包括OAR结构域）的异常PITX3在突变体中表达。我们发现下游基因Foxe3、Prox1和Mip的表达因Pitx3突变而改变，突变体中晶状体囊泡的大量减少。对这些蛋白进行免疫组化分析，观察到相似的谱图。晶体蛋白的表达谱在突变体中也发生了改变。因此，我们推测该突变体的小眼/无晶状体是由PITX3的截断表达导致下游靶点和晶状体纤维蛋白的异常表达引起的。
Microphthalmia is a severe ocular disorder, and this condition is typically caused by mutations in transcription factors that are involved in eye development. Mice carrying mutations in these transcription factors would be useful tools for defining the mechanisms underlying developmental eye disorders. We discovered a new spontaneous recessive microphthalmos mouse mutant in the Japanese wild-derived inbred strain KOR1/Stm. The homozygous mutant mice were histologically characterized as microphthalmic by the absence of crystallin in the lens, a condition referred to as aphakia. By positional cloning, we identified the nonsense mutation c.444C>A outside the genomic region that encodes the homeodomain of the paired-like homeodomain transcription factor 3 gene (Pitx3) as the mutation responsible for the microphthalmia and aphakia. We examined Pitx3 mRNA expression of mutant mice during embryonic stages using RT-PCR and found that the expression levels are higher than in wild-type mice. Pitx3 over-expression in the lens during developmental stages was also confirmed at the protein level in the microphthalmos mutants via immunohistochemical analyses. Although lens fiber differentiation was not observed in the mutants, strong PITX3 protein signals were observed in the lens vesicles of the mutant lens. Thus, we speculated that abnormal PITX3, which lacks the C-terminus (including the OAR domain) as a result of the nonsense mutation, is expressed in mutant lenses. We showed that the expression of the downstream genes Foxe3, Prox1, and Mip was altered because of the Pitx3 mutation, with large reductions in the lens vesicles in the mutants. Similar profiles were observed by immunohistochemical analysis of these proteins. The expression profiles of crystallins were also altered in the mutants. Therefore, we speculated that the microphthalmos/aphakia in this mutant is caused by the expression of truncated PITX3, resulting in the abnormal expression of downstream targets and lens fiber proteins.
登录
查看更多内容
影响因子：
2.5
作者：
Varadaraj, Kulandaiappan;Kumari, Sindhu S.;Mathias, Richard T.
通讯作者：
Mathias, Richard T.
影响因子：
2.5
作者：
Rosemann, Michael;Ivashkevich, Alesia;Graw, Jochen
通讯作者：
Graw, Jochen
影响因子：
--
作者：
Burgess D;Zhang Y;Siefker E;Vaca R;Kuracha MR;Reneker L;Overbeek PA;Govindarajan V
通讯作者：
Govindarajan V
影响因子：
3.7
作者：
Ravenscroft G;Jackaman C;Sewry CA;McNamara E;Squire SE;Potter AC;Papadimitriou J;Griffiths LM;Bakker AJ;Davies KE;Laing NG;Nowak KJ
通讯作者：
Nowak KJ
影响因子：
2.5
作者：
Gage, PJ;Suh, H;Camper, SA
通讯作者：
Camper, SA