BioProject

In ribosome biogenesis, a large fraction of ribosomes is used for producing ribosomal proteins. More...

In ribosome biogenesis, a large fraction of ribosomes is used for producing ribosomal proteins. Here, we deal with the question what fraction of ribosomes should be allocated for synthesis of ribosomal proteins to optimize the cellular economy for growth. We define the "r-fraction" as the fraction of mRNA of the ribosomal protein genes out of the total mRNA and simulated how the amount of the total protein is affected by the r-fraction. Then, we empirically measured the amount of protein and RNA in fission yeast cells cultured at a high or low nitrogen source. In the cells cultured at a low nitrogen source, the r-fraction decreased from 0.46 to 0.42 with a 40% reduction of rRNA, but the reduction of the total protein was smaller at 30%. These results indicate that the r-fraction is internally controlled to optimize the efficiency of protein synthesis at a limited cellular cost. Overall design: Gene expression profile at exponentially-growing phase in the fission yeast cultured at low nitrogen condition. Less...