Northern blot was performed by using a sensitive non-radioactive system with slight modification as described [23 (link)]. Total RNA was extracted using mirVana miRNA isolation kit (Ambion). The quantity and quality of RNA was evaluated by nano-drop spectrophotometer (Thermo Scientific) and agarose gel electrophoresis. A biotin-labeled LNA probe for mmu-mir-451 was used. Five micrograms of the total RNA was resolved on 15% denaturing polyacrylamide gel using the SequaGel UreaGel System (National Diagnostics) and the electrophoresis was done in 1 × Tris-Borate-EDTA buffer (Sigma), and tRNA was visualized using ethidium bromide staining to ensure the quality and relative amount of the RNA. The resolved RNA was transferred to positively charged nylon membrane (Hybond-N+, Amesham Pharmacia Biotech) using a semidry Transblot electrophoresis apparatus (BioRad) and the RNA was chemically cross-linked to the membrane by freshly prepared EDC cross-linking solution [1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and 1-Methylimidazole (Sigma)] at 65°C for 1–2 h. The bioti-nylated products were detected using the Chemiluminescent Nucleic Acid Detection Module (Thermo Scientific) on the Gel Imaging System (BioRad).