Institut de la Vision, INSERM UMR_S968, CNRS UMR 7210, Sorbonne Universités, UPMC Univ Paris 06, 75012 Paris, France, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 503, 75 571 PARIS Cedex 12, France, CNRS-UMR 3347, INSERM U1021, Université Paris-sud11, Centre Universitaire, 91405 Orsay, France, and Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
J Neurosci. 2014 Jan 22;34(4):1530-41. doi: 10.1523/JNEUROSCI.3227-13.2014.
Retinal progenitor proliferation and differentiation are tightly controlled by extrinsic cues and distinctive combinations of transcription factors leading to the generation of retinal cell type diversity. In this context, we have characterized Bcl-2-associated transcription factor (Bclaf1) during rodent retinogenesis. Bclaf1 expression is restricted to early-born cell types, such as ganglion, amacrine, and horizontal cells. Analysis of developing retinas in Bclaf1-deficient mice revealed a reduction in the numbers of retinal ganglion cells, amacrine cells and horizontal cells and an increase in the numbers of cone photoreceptor precursors. Silencing of Bclaf1expression by in vitro electroporation of shRNA in embryonic retina confirmed that Bclaf1 serves to promote amacrine and horizontal cell differentiation. Misexpression of Bclaf1 in late retinal progenitors was not sufficient to directly induce the generation of amacrine and horizontal cells. Domain deletion analysis indicated that the N-terminal domain of Bclaf1 containing an arginine-serine-rich and a bZip domain is required for its effects on retinal cell differentiation. In addition, analysis revealed that Bclaf1 function occurs independently of its interaction with endogenous Bcl-2-related proteins. Altogether, our data demonstrates that Bclaf1expression in postmitotic early-born cells facilitates the differentiation of early retinal precursors into retinal ganglion cells, amacrine cells, and horizontal cells rather than into cone photoreceptors.
视网膜祖细胞的增殖和分化受到外在线索和转录因子的独特组合的严格控制，导致视网膜细胞类型多样性的产生。在这种情况下，我们研究了在啮齿动物视网膜发生过程中的 Bcl-2 相关转录因子（Bclaf1）。Bclaf1 的表达局限于早期出生的细胞类型，如神经节细胞、无长突细胞和水平细胞。在 Bclaf1 缺陷小鼠发育的视网膜中分析表明，视网膜神经节细胞、无长突细胞和水平细胞的数量减少，而视锥细胞前体细胞的数量增加。通过在胚胎视网膜中体外电穿孔 shRNA 沉默 Bclaf1 表达，证实 Bclaf1 有助于促进无长突细胞和水平细胞的分化。在晚期视网膜祖细胞中异位表达 Bclaf1 不足以直接诱导无长突细胞和水平细胞的生成。结构域缺失分析表明，Bclaf1 的 N 端结构域包含富含精氨酸-丝氨酸的结构域和 bZip 结构域，是其对视网膜细胞分化影响所必需的。此外，分析表明 Bclaf1 的功能与其与内源性 Bcl-2 相关蛋白的相互作用无关。总之，我们的数据表明，Bclaf1 在有丝分裂后早期出生的细胞中的表达促进了早期视网膜前体细胞分化为视网膜神经节细胞、无长突细胞和水平细胞，而不是分化为视锥细胞。
