Fig. 4.

piRNA target genes are mostly ribosomal protein pseudogenes. The △CT method was used to investigate changes in expression of in silico-predicted target genes for dysregulated piRNA, according to piRBase and piRNAdb (Table 4). Except for TXRND1, target genes included ribosomal protein pseudogenes, RPL10P7, RPL13AP3, RPL18AP3, and 5S ribosomal RNA pseudogene transcripts, RNA5SP202 and RNA5-8SP6. We investigated the coding gene expression instead of pseudogenes due to increased evidence of ribosomal protein dysregulation in ALS. There was no notable change in gene expression except for expression of RPL13A (p = 0.053). This suggests that these piRNAs have regulatory effects beyond regulation of in silico-predicted target coding genes