Fig. 2. Presence of sequences from the single intron in the N-Zfp36l2 mutant transcript. (A) Total cellular RNA (10 µg per lane) was isolated from the indicated tissues and bone marrow-derived macrophages (BMMac) of wild-type (WT) and N-Zfp36l2 mutant mice, subjected to northern blot analysis and probed with Zfp36l2 intron and Gapd probes, as indicated by the arrows. (B) Cytosolic RNA was extracted from BMMac of WT and mutant mice, and subjected to northern blot analysis. Each lane contained 10 µg of cytosolic RNA probed, respectively, with Zfp36l2 exon 2, intron and Neo probes, as indicated at the top of each pair of lanes. The new transcript present in cytosolic samples from the mutant mice hybridized with both the exon 2 and intron probes, whereas the WT Zfp36l2 transcript hybridized only with the exon 2 probe. The new Zfp36l2 transcript was not fused with Neo, because it did not hybridize with a Neo probe; as shown in the last lane of this panel, the Neo probe hybridized only with the Neo transcript present in the sample from the N-Zfp36l2 mutant cells.