FIG 1.

Organization of the cwlO locus and analysis of the leader sequence. (A) A schematic representation of the cwlO locus with its regulatory features. The cwlO open reading frame is represented by a rectangle. Initiation points of transcription are represented by bent arrows. The DNA recognition sequences for WalR and SigB are indicated by small blue and red boxes, respectively. Transcripts are indicated by broken lines, with the cwlO sense and antisense transcripts indicated by blue and red broken lines, respectively. The two small noncoding RNAs are designated by black broken lines. (B) A potential secondary structure for the cwlO leader sequence. The stem-loop structures are designated (SL1 to -4), the scissors represents the RNase Y cleavage site, and the colored lines delineate the leader regions present in the transcriptional fusions. (C) Sequence of the cwlO promoter, leader sequence, and beginning of the open reading frame. The Pribnow box and initiation point of transcription (+1) are shown in black, the promoter sequence is shown in red, the WalR recognitions sequences are overlined, and the regions of the leader sequence used in the transcriptional analysis are shown in blue, green, orange, and purple. (D) The regions of the leader sequence designated in panels B and C were fused to a promoterless gfpmut3 reporter gene and expression determined by measuring GFP activity throughout a phosphate limitation cycle. The sequence composition of the promoter-plus-leader region used in each transcriptional fusion is indicated by colored lines over each graph. A representative growth curve is shown in panel v. Time is in minutes after culture inoculation.