Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
Proc Natl Acad Sci U S A. 2010 Dec 21;107(51):22140-4. doi: 10.1073/pnas.1012236107. Epub 2010 Nov 15.
Increasing evidence suggests that parentally supplied RNA plays crucial roles during eukaryotic development. This epigenetic contribution may regulate gene expression from the earliest stages. Although present in a variety of eukaryotes, maternally inherited characters are especially prominent in ciliated protozoa, in which parental noncoding RNA molecules instruct whole-genome reorganization. This includes removal of nearly all noncoding DNA and sorting the remaining fragments, producing extremely gene-rich somatic genomes. Chromosome fragmentation and extensive replication produce variable DNA copy numbers in the somatic genome. Understanding the forces that drive and regulate copy number change is fundamental. We show that RNA molecules present in parental cells during sexual reproduction can regulate chromosome copy number in the developing nucleus of the ciliate Oxytricha. Experimentally induced changes in RNA abundance can both increase and decrease the levels of corresponding DNA molecules in progeny, demonstrating epigenetic inheritance of chromosome copy number. These results suggest that maternal RNA, in addition to controlling gene expression or DNA processing, can also program DNA amplification levels.
越来越多的证据表明，亲代提供的 RNA 在真核生物发育过程中发挥着至关重要的作用。这种表观遗传贡献可能从最早的阶段就调节基因表达。尽管存在于各种真核生物中，但母系遗传特征在纤毛原生动物中尤为突出，在这些动物中，亲代非编码 RNA 分子指导全基因组重排。这包括去除几乎所有的非编码 DNA，并对剩余的片段进行分类，产生极度富含基因的体细胞基因组。染色体碎片化和广泛的复制会导致体细胞基因组中 DNA 拷贝数的变化。了解驱动和调节拷贝数变化的力量是至关重要的。我们表明，在有性生殖过程中存在于亲代细胞中的 RNA 分子可以调节纤毛虫 Oxytricha 发育核中的染色体拷贝数。实验诱导的 RNA 丰度变化既能增加也能减少后代中相应 DNA 分子的水平，证明了染色体拷贝数的表观遗传遗传。这些结果表明，除了控制基因表达或 DNA 处理外，母性 RNA 还可以编程 DNA 扩增水平。
