A Small RNA Pathway Mediates Allelic Dosage in Endosperm
A Small RNA Pathway Mediates Allelic Dosage in Endosperm
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DOI：
10.1016/j.celrep.2017.11.078
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发表时间：
2017-12-19
期刊：
影响因子：
8.8
通讯作者：
Gehring, Mary
中科院分区：
文献类型：
--
作者：
Erdmann, Robert M.;Satyaki, Prasad R. V.;Gehring, Mary
三倍体胚乳内母本和父本基因组之间的平衡对于正常种子发育是必要的。大多数胚乳基因以 2:1 母本：父本比例表达，反映了基因组 DNA 含量。在这里，我们发现 2:1 的转录比例出乎意料地受到积极调节。在拟南芥和琴叶拟南芥中，与胚相比，胚乳24-nt小RNA的转座元件减少，基因富集。我们发现 sRNA 和 mRNA 的起源亲本之间存在反比关系，基因更可能与母系偏向的 sRNA 相关，而不是与父系偏向的 sRNA 相关。 Pol IV sRNA 途径的破坏会导致许多基因向母体等位基因 mRNA 表达转变。此外，RNA Pol IV 突变的父系遗传足以挽救因父系基因组剂量过多而导致的种子败育。因此，RNA Pol IV 介导胚乳中母本和父本遗传基因组之间的转录平衡。
Balance between maternal and paternal genomes within the triploid endosperm is necessary for normal seed development. The majority of endosperm genes are expressed in a 2:1 maternal: paternal ratio, reflecting genomic DNA content. Here, we find that the 2:1 transcriptional ratio is, unexpectedly, actively regulated. In A. thaliana and A. lyrata, endosperm 24-nt small RNAs are reduced in transposable elements and enriched in genes compared with the embryo. We find an inverse relationship between the parent of origin of sRNAs and mRNAs, with genes more likely to be associated with maternally than paternally biased sRNAs. Disruption of the Pol IV sRNA pathway causes a shift toward maternal allele mRNA expression for many genes. Furthermore, paternal inheritance of an RNA Pol IV mutation is sufficient to rescue seed abortion caused by excess paternal genome dosage. Thus, RNA Pol IV mediates the transcriptional balance between maternally and paternally inherited genomes in endosperm.