Novel ncRNAs detected by Northern analysis. Four novel ncRNAs were analyzed to validate the tiling array results. All four ncRNAs were detected during exponential and stationary phase grown in defined medium; expression during one growth phase is shown for each ncRNA. Primary transcripts are indicated by an asterisk. Transcription initiation sites identified by 5' RACE are shown in bold and the difference with the estimated transcription initiation sites using the array data are shown between brackets. Genes are represented by bars and arrows indicate the direction of transcription. (A) ReC12 and (B) ReC14 detected during early exponential phase; (C) ReC56 and (D) ReC64 detected during stationary phase.