Figure 3: Regional expression of epididymal piRNAs in aged animals. (a) Profiles of regional sRNA constitution in 13-month-old mouse testis and epididymis by RNA-seq. (b) Composition of sRNA categories according to their length distributions in each sample. (c) Length distribution comparison of piRNAs from different testicular sperm cell types and aged caput epididymidis. (d) Composition of the 5' end nucleotide of piRNAs from each sample. (e) RT-qPCR validation of small RNA-seq data for six selected piRNAs. Quantitative PCR data are presented as mean ± s.d. from three independent animals. The “snRNA Frag”, “rRNA Frag”, and “mRNA Frag” refer to the RNA fragments derived from snRNAs, rRNAs, and mRNAs, respectively. RT-qPCR: quantitative reverse transcription PCR; s.d.: standard deviation; piRNA: P-element-induced wimpy testis (PIWI)-interacting RNA; snRNA: small nuclear RNA; sno-sRNA: small nuclear RNA-derived small RNA; mito-sRNA: mitochondrial RNA-derived small RNA; tsRNA: tRNA-derived small RNA.