罕见先天性小眼畸形中MAB21L1R51W调节Pax6的核内机制研究

罕见先天性小眼畸形（CMIC）多由基因突变所致，尚无有效治疗，因此基因诊断极为重要。本团队前期发现MAB21L1基因（c.151C>T，p.R51W）突变是CMIC的致病性突变。进一步研究显示：该突变可导致斑马鱼出现CMIC表型、抑制Mab21l1的转核、降低眼睛发育关键基因PAX6的表达。结合生物信息学预测，我们提出：MAB21L1突变可能破坏了其与Meis2的共同转位入核，阻断PAX6转录，破坏了眼睛发育过程。为验证该假说，本课题拟在MAB21L1 (R51W)小鼠模型中观察突变对眼睛发育的时空影响；在细胞模型中检测突变对Meis2与Mab21l1的结合和核定位、及PAX6的表达水平的影响；基于CRISPR/Cas9技术修正突变患者来源的iPS细胞，观察晶状体细胞的分化能力。以期揭示MAB21L1在眼睛发育过程中的功能及分子机制，为CMIC的基因诊断和个体化治疗提供新思路。

Congenital microphthalmia (CMIC), which is mainly caused by gene mutations, have no effective therapy so far. The exploration of mutation-related mechanisms is therefore of great necessity. In a CMIC family, our team found a pathogenic mutation in the MAB21L1 gene (c.151C>T, p.R51W). Later, we confirmed that the MAB21L1 (p.R51W) mutation could lead to CMIC phenotype in zebrafish. Also, the mutation inhibited the translocation of Mab21l1 to the nucleus, and down-regulated the PAX6 expression. Protein cluster analysis predicted the interaction between Meis2 and Mab21l1. Here, we hypothesize that Mab21l1 combines with Meis2, translocates into the nucleus with Meis2, activating the transcription of PAX6. The MAB21L1 (p.R51W) mutation, that we found in the CMIC family, will disrupt the process. .The current proposal aim to explore the effects and mechanisms of MAB21L1 (p.R51W) mutation on eye development. In the MAB21L1 (R51W) transgenic mouse model, we will observe the mutation effects on the phenotype development. In the cell models, we will detect the mutation-related effects on the binding and nuclear translocalization of Meis2 and Mab21l1, the expression of PAX6 as well. In the patient-derived iPS cells, we will explore and verify the potential effects of mutation correction with CRISPR/Cas9 technology, especially the differentiation ability of lens epithelial cells into lens fiber cells. .Our study will be helpful to promote the understanding of the role of MAB21L1 in eye development, and provide possible novel targets for the diagnosis and individualized therapy to CMIC.