Determination of 3′ ends of the crp mRNAs. Total RNAs (50 μg) prepared from TA341 (Δcrp) and TA501 (Δcrp ΔssrA) cells harboring pRH31 were hybridized with the Sau3AI-EcoRV fragment 32P-labeled at its Sau3AI 3′ end and the hybrids were treated with 200 U of S1 nuclease. The products were dissolved in 20 μL of loading buffer (8 M urea, 0.025 % bromophenol blue, 0.025 % xylene cyanol, 90 mM Tris-borate, and 1 mM EDTA), and 7 μL of each sample was analyzed on a 8% polyacrylamide-8M urea gel along with products of A+G chemical sequencing reaction of the fragment (lane 1). Both nucleotide (small letter) and amino acid (bold letter) sequences around the rare-codon cluster are shown on the right. The GC-rich inverted repeat sequence of the terminator is indicated by vertical arrows. The arrowheads represent the positions corresponding to the 3′ ends of the crp mRNAs.
