Xenopus pax6 mutants affect eye development and other organ systems, and have phenotypic similarities to human aniridia patients.
Xenopus pax6 mutants affect eye development and other organ systems, and have phenotypic similarities to human aniridia patients.
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DOI：
10.1016/j.ydbio.2015.02.012
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发表时间：
2015-12-15
影响因子：
2.7
通讯作者：
Grainger RM
中科院分区：
文献类型：
--
作者：
Nakayama T;Fisher M;Nakajima K;Odeleye AO;Zimmerman KB;Fish MB;Yaoita Y;Chojnowski JL;Lauderdale JD;Netland PA;Grainger RM
Pax 6基因突变会导致脊椎动物和无脊椎动物的眼部缺陷，以及人类的无虹膜疾病。尽管在包括人类在内的多个物种中对该基因进行了广泛的实验，但我们仍然不了解该基因介导的对发育的最早影响。这促使我们在热带爪蟾中开发pax6突变株系，利用爪蟾系统用于检查早期发育的效用，并建立用于研究人类疾病无虹膜的模型。我们已经通过使用转录激活因子样效应核酸酶（TALEN）构建体在X中进行基因编辑来产生pax6突变体。热带植物具有假定无效突变的胚胎显示出严重的眼睛异常和大脑发育的变化，如通过形态学和基因表达的变化所评估的。我们发现，在这些pax6突变体中，myc基因在发育的早期就被下调，这是一个与多能性和祖细胞维持有关的基因，很可能是pax6在胚胎中某些关键功能的介导者。发育中的大脑和胰腺中基因表达的变化反映了pax 6在发育过程中的其他重要功能。在pax6功能部分丧失的突变中，眼睛发育最初相对正常，但小青蛙显示出不发达的虹膜，类似于在PAX6突变的人类患者中观察到的经典表型（无虹膜）。在这些幼蛙身上观察到的其他眼睛异常，包括白内障和角膜缺陷，在人类无虹膜中也很常见。因此，青蛙模型使我们能够检查pax6病变导致的眼睛形成的最早缺陷，并为理解人类无虹膜表型的发育基础提供了一个有用的模型。
Mutations in the Pax6 gene cause ocular defects in both vertebrate and invertebrate animal species, and the disease aniridia in humans. Despite extensive experimentation on this gene in multiple species, including humans, we still do not understand the earliest effects on development mediated by this gene. This prompted us to develop pax6 mutant lines in Xenopus tropicalis taking advantage of the utility of the Xenopus system for examining early development and in addition to establish a model for studying the human disease aniridia in an accessible lower vertebrate. We have generated mutants in pax6 by using Transcription Activator-Like Effector Nuclease (TALEN) constructs for gene editing in X. tropicalis. Embryos with putative null mutations show severe eye abnormalities and changes in brain development, as assessed by changes in morphology and gene expression. One gene that we found is downregulated very early in development in these pax6 mutants is myc, a gene involved in pluripotency and progenitor cell maintenance and likely a mediator of some key pax6 functions in the embryo. Changes in gene expression in the developing brain and pancreas reflect other important functions of pax6 during development. In mutations with partial loss of pax6 function eye development is initially relatively normal but froglets show an underdeveloped iris, similar to the classic phenotype (aniridia) seen in human patients with PAX6 mutations. Other eye abnormalities observed in these froglets, including cataracts and corneal defects, are also common in human aniridia. The frog model thus allows us to examine the earliest deficits in eye formation as a result of pax6 lesions, and provides a useful model for understanding the developmental basis for the aniridia phenotype seen in humans.