Skip to main content
. 2010 Nov 4;39(5):1843–1854. doi: 10.1093/nar/gkq1065

Figure 5.

Figure 5.

Analysis of the co-expression of the chlamydial ncRNA CTIG270 and the chlamydial ftsI gene in E. coli. (A) A schematic showing the location of CTIG270 and flanking genes. (B) Results of co-expression assays. Samples were prepared using different co-induction protocols and samples were tested for the presence of the FtsI protein and mRNA and CTIG270. The western blot was developed with an α-Flag-tag antibody. The same samples were run on SDS-Page gels as loading controls and stained with Coomassie Blue. Northern blots for ftsI and CTIG270 were done from RNA preparations from the same samples. The co-induction analysis is shown at the top of the figure. The first three lanes show the results when stimulation with arabinose for 5 h is followed by the addition of IPTG for different times (boxed region) as indicated. In the second set of three lanes, IPTG induction for 5 h was followed by induction with arabinose (boxed region) for the times indicated. In the third set of three lanes induction of both the ncRNA and ftsI were stimulated with IPTG and arabinose (boxed region) for the times indicated. The results indicated that expression of CTIG270 results in the degradation of ftsI mRNA. (C) Co-expression controls in which the lanes shown are analogous to lane 9 in Figure 5A in that both plasmids are co-induced for the same length of time. A truncated form of CTIG270 (CTIG270Δ), which does not overlap the 3′-UTR of ftsI, is expressed in lane 1 but has no influence on the expression of FtsI. Expression of full-length CTIG270 however results in the degradation both ftsI mRNA and CTIG270 (Figure 5C, lane 2 and as shown in Figure 5A). Expression of an unrelated ncRNA (IhtA) that acts on hctA mRNA (15) also has very little effect on the expression of FtsI (lane 3). Expression of FtsI was not affected by the presence of the empty vector pRANGER BTB (lane 4). (D) Quantitative RT-PCR analysis of the expression profiles of ftsI and CTIG270 throughout the developmental cycle. Measurements were made in triplicate for each time point.