Analysis of transgenic mice carrying the conditional RPS19R62W construct with (R62W/Cre) and without (R62W/+) the Prion-Cre transgene. (A) Day 13.5 embryos. (B) Three-week-old pups. (C) RNase protection analysis of fetal liver RNA from day 13.5 embryos. Lane 1 indicates RNA from R62W/+ embryo; and lanes 2 to 5, RNA from R62W/Cre embryos. The transgenic RPS19 mRNA protects a 584-bp fragment of the probe. The mouse Rps19 mRNA protects 2 93-bp fragments of the probe, providing an internal control. (D) Northern blot analysis of rRNA processing. The individual rRNA products are indicated at the side of the figure. Lanes 1 and 2 indicate bone marrow RNA from R62W/+ (lane 1) R62W/Cre (lane 2) animals probed with an ITS1 probe; lanes 3 and 4, bone marrow RNA from R62W/+ (lane 3) R62W/Cre (lane 4) animals probed with an ITS2 probe; lanes 5 and 6, bone marrow RNA from R62W/+ (lane 5) R62W/Cre (lane 6) animals probed with an 18s rRNA probe. The apparent increases in the level of 21s (ITS1) and 12s (ITS2) are the result of the increased amount of R62W/Cre RNA in lanes 2, 4, and 6 as demonstrated by the level of 18s hybridization.