Nat Cell Biol：miR-675调控胎盘的生长

近日，Babraham研究所的科学家们对胎儿出生前胎盘的生长情况已经获得了新的认识，这对健康怀孕有重要意义。研究结果发表在6月10日的Nature Cell Biology杂志上，研究证实miR-675在胎儿出生前能使得胎盘的生长速度变慢。

RNA分子是细胞DNA和细胞功能所必需的物质中介，Babraham研究所的科学家们正在研究这些非编码RNA包括小分子RNA（短的非编码RNA分子类型）是如何调节细胞的发育和功能的。

非编码RNA H19的是在哺乳动物中发现的最多的RNA分子之一，但到现在为止，它的功能却是未知的。在这项研究中，研究人员首次表明RNA H19的一种miR-675能限制胎盘的生长。

Babraham研究所Andrew Keniry博士解释说， miR-675的释放由一种应激反应蛋白控制，提示这可能是胚胎发育机制过程中调控胚胎在子宫内生长的关键所在。（生物谷：Bioon.com）

doi:10.1038/ncb2521
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The H19 lincRNA is a developmental reservoir of miR-675 that suppresses growth and Igf1r

Andrew Keniry,David Oxley,Paul Monnier,Michael Kyba,Luisa Dandolo,Guillaume Smits& Wolf Reik

The H19 large intergenic non-coding RNA (lincRNA) is one of the most highly abundant and conserved transcripts in mammalian development, being expressed in both embryonic and extra-embryonic cell lineages, yet its physiological function is unknown. Here we show that miR-675, a microRNA (miRNA) embedded in H19’s first exon, is expressed exclusively in the placenta from the gestational time point when placental growth normally ceases, and placentas that lack H19 continue to grow. Overexpression of miR-675 in a range of embryonic and extra-embryonic cell lines results in their reduced proliferation; targets of the miRNA are upregulated in the H19 null placenta, including the growth-promoting insulin-like growth factor 1 receptor (Igf1r) gene. Moreover, the excision of miR-675 from H19 is dynamically regulated by the stress-response RNA-binding protein HuR. These results suggest that H19’s main physiological role is in limiting growth of the placenta before birth, by regulated processing of miR-675. The controlled release of miR-675 from H19 may also allow rapid inhibition of cell proliferation in response to cellular stress or oncogenic signals.