Schematic diagram of the <i>miR-322/503</i> knockout locus and the mating schedule.

<p>(<b>A</b>) <i>Mirc24</i>^{<i>tm1Mtm</i>}/ Mmjax mice were crossed with Tg(<i>Sox2-Cre</i>) mice. Due to the presence of three LoxP sites, there were three possible alleles resulted from Cre-mediated recombination. We selected the one (dotted-box) with the <i>miR-322/503</i> stemloop ablated to carry out further mating and named it “<i>miR-322/503</i> KO”. (<b>B</b>) E8.5 embryos were produced from mating of male hemizygous knockout of <i>miR-322/503</i> (<i>miR-322/503</i>^-/Y) with female wildtype SW mice. Half of the embryos are expected to be heterozygous knockout female mice (<i>miR-322/503</i>^-/+) and also <i>LacZ</i> positive.