Identification of tRNA-derived fragments across planarian body axis. (A) Percentage distribution of all the identified small RNAs across the sections of planarian body. (B) Percentage distribution of small RNA reads mapping to tRNAs across planarian body sections. Small RNA reads are segregated into 18–24 nt and 25–35 nt. (C) Per base coverage of 18–24 nt reads across parent tRNA length. (C′) Per base coverage of 25–35 nt reads across parent tRNA length. (D) Pictorial depiction of the three tRNA-derived fragments identified in this study. (E) Pie chart depicting the percentage distribution of 5′-tsRNAs, tRF-5s, and itRFs in planaria. (F) Northern blots of top enriched 5′-tsRNAs (pseudo-GlyGCC and UNDET Gly-17). As controls, Sup-TTA (which does not generate 5′-tsRNAs) was probed in addition to probing the 3′ regions of UNDET Gly-17 to detect the presence 3′ tRFs. The two lanes represent replicates. (F′) Stem–loop RT-PCR validation of top planarian 5′-tsRNA, tRF-5s, and itRFs run on 10% PAGE. The gray arrowhead points to the product without any insert (∼60 bp). The red arrowhead and blue arrowhead point to sizes of tsRNA (∼80 bp) and tRF (∼70 bp) amplicons, respectively.
