U6 snRNA in PN patient lymphoblasts is aberrantly 3′ oligoadenylated. (A) PCR analysis of U6 snRNA 3′ tails from control (HC) and 3 independent PN patient (DC, ML, RT) lymphoblasts separated on an Agilent bioanalyzer. (B) Frequency distribution of the number of nontemplated nucleotides at the U6 3′ terminus in the same 4 lymphoblast cell lines as indicated determined by MiSeq analysis. (C) Sequences of nontemplated nucleotides at the 3′ end of U6 snRNA in control lymphoblasts (sample HC). Reads containing uridine residues alone are shown in blue, reads with a single 3′ terminal adenine nucleotide are in red. Sequences represented by less than 1000 reads are excluded. (D) Sequences of nontemplated nucleotides at the 3′ end of U6 snRNA from PN patient lymphoblasts (sample RT). Sequences are grouped according to the number of consecutive adenine nucleotides at the U6 3′ end. Sequences represented by less than 1000 reads are not included.