library_construction_protocol: The selected cells were processed for single-cell RNA extraction and reverse transcription within 1 h and were subjected to cDNA amplification and purification. Single cells were gently transferred into lysis buffer, and reverse transcription was performed using a SMARTer Ultra Low RNA Kit (Clontech) directly in the cell lysate. Single-cell cDNA was amplified using an Advantage 2 PCR Kit (Clontech) according to the manufacturer's protocol. After cDNA amplification, 50 μl of the sample was subjected to cDNA purification, whereas the remaining sample was kept for single-cell PCR experiments.