“…Although the presence of 3′ UTR RNAs lacking the coding region has been observed previously in some instances (Carninci et al, 2006; Kocabas et al, 2015; Malka et al, 2017; Mercer et al, 2011), the mechanism of their biogenesis remains elusive. Analyzing total RNA sequencing data from several mouse tissues and the mouse NIH 3T3 cell line, we identified several genes, including Frat2 , Hnrnpa0 , and Sox12 , that had read densities at least several-fold higher in the 3′ UTR than in the coding region in most or all of these samples (Figures S1G and S1H).…”