Skip to main content
. Author manuscript; available in PMC: 2013 Dec 1.
Published in final edited form as: Mol Microbiol. 2012 Oct 12;86(5):1167–1182. doi: 10.1111/mmi.12050

Figure 4. Effect of mini-ORF mutations on esp mRNA concentration.

Figure 4

(A) Sequences of the mini-ORF and part of the intergenic region in the wild-type plasmid pPL1 and its mutated derivatives. The mutations, which are depicted in capital letters and underlined, were introduced into the mini-ORF region and include: the SD2 element (pmut-SD2, same as Figure 3), start codon (pmut-TTG and pmut-TTG-2), and the third codon (pORF-TAA). The mini-ORF SD2 and start codon are shown in uppercase letters.

(B) Analysis by Northern blotting of esp mRNA levels in EHECΔLEE transformed with plasmid pPL1 and its derivatives. Total RNA was extracted from cells grown in DMEM 0.2% glucose. The blot was hybridized with an espA-specific probe (EspA3), then stripped and re-hybridized with a probe for 16S rRNA.

(C) Quantification of esp transcript concentrations from Northern blots as shown in (B). For each lane, the esp band intensity was normalized to that of 16S rRNA to compensate for loading variations. Each ratio (± SD) is expressed relative to the normalized transcript level in EHECΔLEE(pPL1). The asterisk denotes that the difference in transcript levels is statistically significant (one sample, two sided t test, α= 0.05, P=0.0043).