Primer extension assay carried out on total RNA extracted from cells grown to stationary phase.

<p>³²P 5'-end labelled K12 primer was extended with the Superscript II reverse transcriptase and resolved on 7% polyacrylamide gel. Major bands are delineated in the schematic of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013449#pone-0013449-g001" target="_blank">figure 1</a>. P1 represents the longest transcript (> 800 nt); P2 is somewhat shorter (> 650 nt); R3 (∼ 600). An additional band of unexplained origin, X, is also indicated in the figure. Band 2a is seen to be accompanied by an additional unlabelled band in the <i>rnc</i>^- mutant.