概括
成熟的海刺卵细胞在其RNA中表达重复的DNA序列. 大多数短间隔的重复序列和许多长的重复序列都被转录,其流行程度各不相同.
科学领域:
- 分子生物学分子生物学
- 发展生物学 发展生物学
- 基因组学就是基因组学.
背景情况:
- 间隔的重复序列 (IRS) 在真核生物基因组中很丰富.
- 它们在卵细胞中的表达对早期发育至关重要.
- 了解海卵细胞中的IRS转录,可以深入了解基因组调节.
研究的目的:
- 研究成熟海卵细胞中短和长间隔的重复序列的表达.
- 为了确定这些转录的重复序列的流行率和链表征.
- 为了将转录的流行与基因组重复频率和基因组组织相关联.
主要方法:
- 为短 (数百个核酸) 和长 (大约100个核酸) 的3H-DNA痕迹剂的制备. 2000个核酸) 的重复序列从Strongylocentrotus purpuratus基因组DNA中插入.
- 这些标志物与过多成熟卵细胞RNA的杂交.
- 动力学分析以确定转录的流行率.
- 九个克隆的重复序列与卵细胞RNA的链分离和杂交.
- 对转录的重复序列的基因组组织的分析.
主要成果:
- 大约80%的短重复标记物和35%的长重复标记物与卵细胞RNA杂交.
- 检测到对大多数重复序列的两个链子互补的转录.
- 转录的发病率差异很大,从大约10^3到每卵细胞超过10^5个副本.
- 转录的流行程度独立于基因组重复频率.
- 普遍的转录来源于具有低基因组拷贝数 (<200个单 haploid 基因组) 的重复性家族.
- 大多数流行的转录家族的成员都间隔着单复制序列.
结论:
- 成熟的海卵细胞积极转录它们间隔的重复序列的很大一部分.
- 短和长间隔的重复序列都在卵细胞RNA中表现出来,流行率各不相同.
- 转录的流行率与基因组中重复的副本数量没有直接联系,这表明复杂的调节机制.
- 这些发现突出了 oogenesis 期间重复元素的动态表达和基因组组织.
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