RNA profiling of skeletal muscle in RP58 knockout mice

To predict RP58-regulated genes involved in skeletal myogenesis, RNA profiling experiments were performed, comparing RNA derived from skeletal muscle tissue of a RP58+/+ mouse to that from a RP58 knockout (KO) mouse at E18.5. Importantly, well-known dominant-negative inhibitors of muscle differentiation, the Id family of genes (Id1/Id2/Id3), were upregulated in the RP58 KO muscle. On the contrary, a number of muscle differentiation-related genes, such as Ckm, troponin and Myosin, were downregulated in the same sample. These results indicate that the repressor protein RP58 is important for muscle terminal differentiation, possibly suppressing the gene expression of muscle differentiation genes such as the Ids. Keywords: Knockout tissue Skeletal muscles of WT and RP58 KO mice (E18.5 diaphragm) were dissected under a microscope and RNA was extracted using ISOGEN (Nippongene). After EtOH precipitation, RNA was dissolved into DEPC-DW and its concentration was determined. Microarray analysis - cRNA was synthesized. 10 ug of cRNA were hybridized to Affymetrix mouse 430A 2.0 arrays. Signal intensities were calculated using the RMA method. MAPPFinder (www.genmapp.org) was used to integrate expression data with known pathways.