β-galactosidase reporter assays for consensus Correia ends.

1The consensus CE ends shown in Figure 1B (along with 4 nucleotides immediately upstream of the Correia repeat and the downstream flanking dinucleotide “AT”) were cloned into a low-copy lacZ reporter plasmid (pRC746). Details are provided in Table S1. The E. coli host strain is MC4100.2β-galactosidase activity is measured in Miller units. The following formula was used to calculate Miller units: [(spectrophotometer reading at 420 nm wavelength)×1000]/[(spectrophotometer reading at 600 nm wavelength)×(cell volume (mls))×(time (mins))].3Based on results from 3 independent experiments.4Relative to vector control (pRC746).5Unless designated otherwise, the base at position 128 is cytosine.6Altered −10 and −35 box sequences are shown in Figure 1B.