FIGURE 4.

Effects of miR-122 abundance on the 3′ terminal polyadenosine length of Insig1 isoforms. (A) Effects of miR-122 and miR-106b/93 sequestration on Insig1 isoform RNA abundances. Cells were transfected simultaneously with indicated antisense LNA oligonucleotides and the YFP-Insig1-3′NCR encoding plasmids and allowed to recover for 28 h. Cells were then depleted of sterols for 14 h and RNA was harvested. Insig1 isoforms were examined in a Northern blot using a hybridization probe against the YFP open reading frame. Plasmid Δ205 lacks the first 205 nt of the Insig1 3′NCR. (B) Poly(A) tail length measurements in Insig1 isoform mRNAs. Cells were treated as in panel A. Purified mRNA was hybridized to oligo(dT) and treated with RNase H. Shown is a Northern blot using a hybridization probe against the YFP open reading frame.