miR-148a is a downstream effector of X-box-binding protein 1 that silences Wnt10b during adipogenesis of 3T3-L1 cells.

Fat cell development is driven in part via the production of a small RNA molecule that eliminates obstacles to cellular maturation. Several studies have shown that a protein known as X-box binding protein 1 (XBP1) is essential for fat cell differentiation by regulating levels of many proteins Researchers led by Oh-Joo Kwon at the Catholic University of Korea have shown that XBP1 achieves this by eliminating the RNA messages encoding Wnt10b, a protein that maintains precursor cells in an immature state. In a series of experiments, Kwon and colleagues showed that XBP1 stimulates the production of microRNA-148a, a small RNA molecule that binds to and destabilizes Wnt10b mRNA. The degradation of this mRNA sharply reduces production of Wnt10b, freeing precursor cells to produce a host of other proteins that contribute to the fat cell developmental process.