Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea.
Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.
Elife. 2018 Oct 30;7:e39381. doi: 10.7554/eLife.39381.
The first wave of transcriptional activation occurs after fertilisation in a species-specific pattern. Despite its importance to initial embryonic development, the characteristics of transcription following fertilisation are poorly understood in Aves. Here, we report detailed insights into the onset of genome activation in chickens. We established that two waves of transcriptional activation occurred, one shortly after fertilisation and another at Eyal-Giladi and Kochav Stage V. We found 1544 single nucleotide polymorphisms across 424 transcripts derived from parents that were expressed in offspring during the early embryonic stages. Surprisingly, only the maternal genome was activated in the zygote, and the paternal genome remained silent until the second-wave, regardless of the presence of a paternal pronucleus or supernumerary sperm in the egg. The identified maternal genes involved in cleavage that were replaced by bi-allelic expression. The results demonstrate that only maternal alleles are activated in the chicken zygote upon fertilisation, which could be essential for early embryogenesis and evolutionary outcomes in birds.
受精后发生第一波转录激活，具有种特异性模式。尽管这对初始胚胎发育很重要，但在禽类中，受精后转录的特征知之甚少。在这里，我们报告了鸡基因组激活起始的详细信息。我们确定发生了两波转录激活，一波在受精后不久，另一波在 Eyal-Giladi 和 Kochav 阶段 V。我们发现 424 个转录本中有 1544 个单核苷酸多态性来自父母，这些转录本在胚胎早期阶段在后代中表达。令人惊讶的是，只有母本基因组在受精卵中被激活，而父本基因组在第二波激活之前一直保持沉默，无论卵子中是否存在父本原核或额外的精子。鉴定出的母本基因参与卵裂，由双等位基因表达取代。结果表明，在鸡受精卵受精后，只有母本等位基因被激活，这对鸟类的早期胚胎发生和进化结果可能至关重要。
