Preprocessing of reads was done automatically with workflow tool seq2science v0.5.4. Single-end reads were trimmed with fastp v0.20.1 with default options. Genome assembly mm10 was downloaded with genomepy 0.9.3. The genome and gene annotations was extended with custom regions. Reads were aligned and transformed to bus format with kb-python v0.26.3, a python wrapper for kallisto and bustools. Quality control metrics were aggregated by MultiQC v1.11.