library_construction_protocol: Lysing cells to obtain a cell lysate; digesting RNA not protected by ribosomes using RNase; performing high-density sucrose centrifugation to isolate monosomes (single ribosomes); extracting and purifying the short, undigested mRNA fragments from the ribosomes; ligating specific sequence adapters; constructing a library via PCR. By enriching for monosomes, short undigested mRNA fragments bound to ribosomes were obtained. Adapters were ligated to the 3' and 5' ends of the mRNA, followed by reverse transcription to synthesize cDNA and subsequent PCR amplification, resulting in the final sequencing library. After quality inspection, the library was subjected to sequencing.