Insulin-like growth factor 1 (IGF1) is a key protein that contributes to control of an organism’s size after birth and during development, whereas IGF2 is the main regulator of growth and body size during fetal development. A study in Cell Reports describes a mechanism by which a microRNA produced from Igf2 regulates IGF1 to suppress growth in mice.

The researchers then assessed the effect of miR-483 on fetal and postnatal development and growth. “We made a knockout mouse and two types of mouse lines that make more copies of miR-483 than the normal levels; one coming from the ‘endogenous’ location at the Igf2 gene and one from another genomic location,” says corresponding author Miguel Constância. Knockout of miR483 (Mir483^Pat-KO mice) did not result in a noticeable phenotypic change. Overexpression of Mir-483 during fetal development, however, universally led to fetal death.

胰岛素样生长因子 1 （IGF1） 是一种关键蛋白质，有助于控制出生后和发育过程中生物体的大小，而 IGF2 是胎儿发育过程中生长和体型的主要调节因子。Cell Reports 上的一项研究描述了 Igf2 产生的 microRNA 调节 IGF1 以抑制小鼠生长的机制。

然后，研究人员评估了 miR-483 对胎儿和出生后发育和生长的影响。“我们制作了一只基因敲除小鼠和两种类型的小鼠细胞系，它们产生的 miR-483 拷贝数超过正常水平;一个来自 Igf2 基因的'内源性'位置，另一个来自另一个基因组位置，“通讯作者 Miguel Constância 说。敲除 miR483 （Mir483^Pat-KO 小鼠） 未导致明显的表型变化。然而，在胎儿发育过程中过表达 Mir-483 普遍导致胎儿死亡。