MAPK3 and obesity due to melanocortin 4 receptor deficiency: UBC-cre/ERT2; mir-7fl/fl mice displayed a more pronounced obesity phenotype than Sim1-cre;mir-7fl/fl mice, suggesting that miR-7 in other unidentified cell population(s) or an additive effect of miR-7 in multiple hypothalamic cell types may be implicated in weight regulation.