Embryonic ethanol exposure alters expression of sox2 and other early transcripts in zebrafish, producing gastrulation defects. Embryonic ethanol exposure alters expression of sox2 and other early transcripts in zebrafish, producing gastrulation defects

Ethanol exposure during prenatal development causes fetal alcohol spectrum disorder (FASD), the most frequent preventable birth defect and neurodevelopmental disability syndrome. The molecular targets of ethanol toxicity during development are poorly understood. Developmental stages surrounding gastrulation are very sensitive to ethanol exposure. To understand the effects of ethanol on early transcripts during embryogenesis, we treated zebrafish embryos with ethanol during pre-gastrulation period and examined the transcripts by Affymetrix GeneChip microarray before gastrulation. We identified 521 significantly dysregulated genes, including 61 transcription factors in ethanol-exposed embryos. Sox2, the key regulator of pluripotency and early development was significantly reduced. Functional annotation analysis showed enrichment in transcription regulation, embryonic axes patterning, and signaling pathways, including Wnt, Notch and retinoic acid. We identified all potential genomic targets of 25 dysregulated transcription factors and compared their interactions with the ethanol-dysregulated genes. This analysis predicted that Sox2 targeted a large number of ethanol-dysregulated genes. A gene regulatory network analysis showed that many of the dysregulated genes are targeted by multiple transcription factors. Injection of sox2 mRNA partially rescued ethanol-induced gene expression, epiboly and gastrulation defects. Additional studies of this ethanol dysregulated network may identify therapeutic targets that coordinately regulate early development. Overall design: control vs. ethanol treated embryos

产前乙醇暴露可引发胎儿酒精谱系障碍（Fetal Alcohol Spectrum Disorder, FASD），这是目前最为常见的可预防性出生缺陷与神经发育残疾综合征。学界对发育过程中乙醇毒性的分子靶点仍知之甚少。原肠胚形成前后的发育阶段对乙醇暴露极为敏感。为探究乙醇对胚胎发生早期转录本的影响，我们在原肠胚前期对斑马鱼胚胎施加乙醇处理，并在原肠胚形成前通过Affymetrix基因芯片（Affymetrix GeneChip）微阵列对转录本进行检测。我们在乙醇暴露的胚胎中共鉴定出521个显著异常表达的基因，其中包含61个转录因子。作为多能性调控与早期发育的关键调节因子，Sox2的表达水平显著下调。功能注释分析显示，这些异常表达基因富集于转录调控、胚胎轴模式建成以及Wnt、Notch、视黄酸等信号通路中。我们还鉴定了25个异常表达转录因子的全部潜在基因组靶点，并将其与乙醇诱导的异常表达基因进行相互作用比对分析。该分析预测，Sox2靶向了大量乙醇诱导的异常表达基因。基因调控网络分析显示，多数异常表达基因可被多个转录因子共同靶向。向胚胎注射sox2 mRNA可部分挽救乙醇诱导的基因表达异常、外包运动与原肠胚形成缺陷。对该乙醇异常调控网络的进一步研究，或可鉴定出协同调控早期发育的治疗靶点。实验设计：对照组与乙醇处理组胚胎的比对