Neural Stem-Cell Commitment

anti-let-7 sponge[Artifically engineered RNA]

let-7a[miRNA]

NA[mRNA]

Neural Stem Cell

Homo sapiens (human)

Nat Cell Biol 2008 Aug 10, 987-93 doi:10.1038/ncb1759 PMID:18604195

A feedback loop comprising lin-28 and let-7 controls pre-let-7 maturation during neural stem-cell commitment.

Western blot;qRT-PCR;luciferase reporter assays

We tested the ability of so-called sponge constructs to de-repress the let-7 and mir-125 target gene lin-41. Sponge constructs express an mRNA with cloned arrays of semi-complementary binding sites for a specific miRNA in the 3'UTR, and function as competitive inhibitors26 . Lin-41 is a marker of undif- ferentiated ES and EC cells27 , and is expressed at low levels in NS cells. Transfection of NS cells with sponge constructs targeting either let-7 or mir-125 increased the level of Lin-41 protein, compared with the sponge vector alone or a sponge construct targeting mir-29. This result demonstrates that mRNAs targeted by let-7 and mir-125, such as lin-41, are subject to ongoing post-transcriptional suppression in NS cells.