Northern blot analysis of mRNA in CS101 (wt), CS101 sagA/pel::Tn917 (pel-) and CS101 sagA/pel::Tn917 kidney-recovered (KR). Bacteria were grown overnight at 37°C, 10% CO2 in Todd-Hewitt Yeast extract broth. RNA was extracted and 10 μg or 1 μg of total RNA was loaded on a 1.0% MOPS-formaldehyde agarose gel. After blotting the RNA to a charged nylon filter, sagA/pel RNA was detected using a biotinylated probe. t1 and t2 represent the two transcripts detected in the wild type strain. Only t1 was detected in the KR variant.