Fig. 4.

Expression levels of Pol III transcripts in the cerebrum and liver of Polr3a KI/KI and KI/KO mice. a) Top: Northern blots of precursor (pre) and mature (m) tRNA species from the cerebrum (left) and liver (right) of 365 days old mice. U3 snRNA was used as a loading control. Bc1 RNA was probed in the cerebrum only. Mean +/− SEM of tRNA or Bc1 levels normalized to U3 snRNA levels are indicated below the blot for each transcript. Bottom: Quantification of Pol III transcripts surveyed by Northern Blot. tRNA levels were normalized to U3 snRNA levels. Data are represented as mean +/− SEM. b) Left: Northern blot of precursor (pre) and mature (m) n-Tr20 tRNA^Arg(UCU) in the cerebrum of 3-months-old mice, demonstrating low levels of n-Tr20, consistent with these mice having the C57BL/6 J n-Tr20 genotype (see also Additional file 1: Figure S6B). Right: Quantification of precursor and mature n-Tr20 levels, normalized to U3 snRNA levels