Umali Jurgienne, Hawkey-Noble Alexia, French Curtis R
Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, Canada.
Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, Canada.
Vision Res. 2019 Mar;156:66-72. doi: 10.1016/j.visres.2019.01.008. Epub 2019 Feb 2.
Mutation of FOXC1 causes Axenfeld-Rieger Syndrome (ARS) with early onset or congenital glaucoma. We assessed retinal ganglion cell (RGC) number in zebrafish due to CRISPR-mediated mutation and antisense inhibition of two-forkhead box transcription factors, foxc1a and foxc1b. These genes represent duplicated homologues of human FOXC1. Using a CRISPR induced null mutation in foxc1b, in combination with antisense inhibition of foxc1a, we demonstrate reduced cell number in the retinal ganglion cell layer of developing zebrafish eyes. As early as 5 days post fertilization (dpf), fewer RGCs are found in foxc1b homozygous mutants injected with foxc1a morpholinos, and a thinner optic nerve results. Our data illustrates that foxc1 is required for the expression of atonal homolog 7 (atoh7), a gene that is necessary for RGC differentiation. As markers of differentiated RGCs (pou4f2) are downregulated in foxc1b-/- mutants injected with foxc1a morpholinos and no cell death is observed, our results are consistent with defects in the differentiation of RGCs leading to reduced cell number, as opposed to increased cell death of RGCs or off targets effects of morpholino injection. Our zebrafish model demonstrates that aberrant regulation of RGC number could act in concert with other known glaucoma risk factors to influence the development of congenital and early onset glaucoma due to FOXC1 mutation.
FOXC1基因突变会导致阿克森费尔德-里格尔综合征（ARS），伴有早发性或先天性青光眼。我们评估了斑马鱼视网膜神经节细胞（RGC）的数量，这是由于CRISPR介导的突变以及对两个叉头框转录因子foxc1a和foxc1b的反义抑制所致。这些基因代表人类FOXC1的重复同源物。通过在foxc1b中使用CRISPR诱导的无效突变，并结合对foxc1a的反义抑制，我们证明了发育中的斑马鱼眼睛视网膜神经节细胞层中的细胞数量减少。早在受精后5天（dpf），在注射了foxc1a吗啉代寡核苷酸的foxc1b纯合突变体中发现的RGC较少，并且视神经变细。我们的数据表明，foxc1是无调性同源物7（atoh7）表达所必需的，atoh7是RGC分化所必需的基因。由于在注射了foxc1a吗啉代寡核苷酸的foxc1b - / - 突变体中，分化的RGC标记物（pou4f2）被下调，并且未观察到细胞死亡，我们的结果与RGC分化缺陷导致细胞数量减少一致，这与RGC细胞死亡增加或吗啉代注射的脱靶效应相反。我们的斑马鱼模型表明，RGC数量的异常调节可能与其他已知的青光眼风险因素共同作用，影响由于FOXC1突变导致的先天性和早发性青光眼的发展。
