Fig 4.
Absence of Lmo1722 alters rRNA processing and ribosomal maturation. (A) Western blot analysis of Lmo1722 expression levels in the indicated strains grown at 16°C. The arrows indicate Lmo1722 and Lmo1722ΔCT. The background signal in the Δlmo1722 plus pIMK3 strain probably reflects expression of Lmo1450, an RNA helicase 32% identical to Lmo1722 and with a similar calculated molecular mass of 50 kDa. (B) Ribosomal profile analysis. Samples from the indicated strains grown at 16°C were prepared and separated by sucrose gradient. The gradients were normalized by the addition of equivalent A260 units, as described in Materials and Methods. The numbered arrows indicate samples used in Fig. 5. The different ribosomal subunits are indicated above the peaks for the wild-type plus pIMK3 profile. (C) Relative processing of immature versus mature 23S rRNA transcripts in the indicated strains grown at 16°C (see the text for details). The error bars indicate standard deviations of the means from three experiments.