Hu Shenqiang, Yang Shuang, Lu Yao, Deng Yan, Li Li, Zhu Jiaran, Zhang Yuan, Hu Bo, Hu Jiwei, Xia Lu, He Hua, Han Chunchun, Liu Hehe, Kang Bo, Li Liang, Wang Jiwen
Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China.
Front Cell Dev Biol. 2020 Apr 3;8:196. doi: 10.3389/fcell.2020.00196. eCollection 2020.
In contrast to the situation in mammals, very little is known about the molecular mechanisms regulating early avian ovarian development. This study aimed to investigate the dynamic changes in the histomorphology as well as the genome-wide transcriptome and chromatin accessibility landscapes of the goose ovary during late embryonic and early post-hatching stages. Results from hematoxylin-eosin, periodic acid-Schiff, and anti-CVH immunohistochemical stainings demonstrated that programmed oocyte loss, oocyte nest breakdown and primordial follicle formation, and the primordial-to-secondary follicle transition occur during the periods from embryonic day 15 (E15) to post-hatching day 0 (P0), from P0 to P4, and from P4 to P28, respectively. RNA-seq and ATAC-seq analyses revealed dynamic changes in both the ovarian transcriptome and accessible chromatin landscapes during early ovarian development, exhibiting the most extensive changes during peri-hatching oocyte loss, and moreover, differences were also identified in the genomic distribution of the differential ATAC-seq peaks between different developmental stages, suggesting that chromatin-level regulation of gene expression is facilitated by modulating the accessibility of different functional genomic regions to transcription factors. Motif analysis of developmental stage-selective peak regions identified hundreds of potential -regulatory elements that contain binding sites for many transcription factors, including SF1, NR5A2, ESRRβ, NF1, and THRβ, as well as members of the GATA, SMAD, and LHX families, whose expression fluctuated throughout early goose ovarian development. Integrated ATAC-seq and RNA-seq analysis suggested that the number and genomic distribution of the newly appeared and disappeared peaks differed according to developmental stage, and in combination with qRT-PCR validation potentiated the critical actions of the DEGs enriched in cell cycle, MAPK signaling, and FoxO signaling pathways during peri-hatching oocyte loss and those in ligand-receptor interaction, tissue remodeling, lipid metabolism, and Wnt signaling during primordial follicle formation and development. In conclusion, our study provides a framework for understanding the transcriptome and accessible chromatin dynamics during early avian ovarian development and a new avenue to unravel the transcriptional regulatory mechanisms that facilitate the occurrence of relevant molecular events.
与哺乳动物的情况不同，目前对于调控禽类早期卵巢发育的分子机制知之甚少。本研究旨在调查鹅卵巢在胚胎后期和孵化后早期阶段的组织形态学、全基因组转录组以及染色质可及性图谱的动态变化。苏木精-伊红染色、过碘酸-希夫染色和抗CVH免疫组织化学染色结果表明，程序性卵母细胞丢失、卵母细胞巢解体和原始卵泡形成，以及原始卵泡向次级卵泡的转变分别发生在胚胎第15天（E15）至孵化后第0天（P0）、P0至P4以及P4至P28期间。RNA测序和ATAC测序分析揭示了卵巢转录组和可及染色质图谱在卵巢早期发育过程中的动态变化，在孵化期周围的卵母细胞丢失期间表现出最广泛的变化，此外，还确定了不同发育阶段之间差异ATAC测序峰的基因组分布差异，这表明通过调节不同功能基因组区域对转录因子的可及性来促进基因表达的染色质水平调控。对发育阶段选择性峰区域的基序分析确定了数百个潜在的调控元件，这些元件包含许多转录因子的结合位点，包括SF1、NR5A2、ESRRβ、NF1和THRβ，以及GATA、SMAD和LHX家族的成员，它们的表达在鹅卵巢早期发育过程中波动。综合ATAC测序和RNA测序分析表明，新出现和消失的峰的数量和基因组分布因发育阶段而异，并结合qRT-PCR验证，强化了在孵化期周围卵母细胞丢失期间富集于细胞周期、MAPK信号通路和FoxO信号通路的差异表达基因，以及在原始卵泡形成和发育期间富集于配体-受体相互作用、组织重塑、脂质代谢和Wnt信号通路的差异表达基因的关键作用。总之，我们的研究为理解禽类早期卵巢发育过程中的转录组和可及染色质动态提供了一个框架，并为揭示促进相关分子事件发生的转录调控机制开辟了一条新途径。
