Construction of the rrp1mut mutant and its complemented rrp1com strain. (a) To construct the rrp1::kan plasmid, the entire ORF of bb0419 (rrp1) was PCR amplified. A kan cassette was inserted into the XbaI and BalI cut sites that are present within the rrp1 ORF, resulting in a 151-bp deletion, generating the rrp1::kan plasmid. (b) Pbb0420, 218 bp from the upstream region of bb0420 that contains the native promoter of the bb0419-bb0420 operon, was PCR amplified and fused to the 5′ end of bb0419. The obtained fragment was then inserted into the pCisCom construct at the BamHI cut site, yielding Rrp1/cis com. (c) Immunoblot analysis of the whole-cell lysate of the wild-type (WT), rrp1mut, and rrp1com strains probed with a specific antibody against Rrp1. DnaK was used as an internal control, as previously described (). α, anti-.