Fig. 4

Differential expression of mRNP granule proteins in proliferating, quiescent and differentiated muscle cells in culture. a Schematic depicts segregation of transcripts into translating and non-translating pools on emergence from the nucleus with a constellation of RNA-binding proteins. Non-translated transcripts may be sequestered in mRNPs enriched for decay complex (mRNA turnover) or storage granule components (translational repression/stabilization of mRNA). b Western blot analysis showing that three distinct cellular states can be distinguished by expression of Myogenin and Cyclin D1 (MB: asynchronously proliferating myoblasts are CycD1+, MyoG-; MT: 5-day differentiated myotubes are CycD1-, MyoG+; G0: quiescent myoblasts are CycD1-, MyoG-). c Western blot profile of mRNP granule protein expression across three cellular states. MB: proliferating myoblasts; G0: quiescent myoblasts; MT: differentiated myotubes. Expression of most proteins is suppressed in G0; notable exceptions are Fmrp and Tia1, which are maintained in G0 (see Table 1 and quantification in Fig. 4d). d Quantification of relative expression of mRNP granule proteins across the three cellular states calculated from densitometric analysis of immuno-blots. Each protein was normalized to Gapdh in the same sample, before normalizing to MB. Values represent mean + SD, n = 3, two-tailed paired Student’s t tests are indicated as [* p ≤ 0.05, ** p ≤ 0.01]