Nucleotide sequence and copy control function of the extension of the incI region (incI-b) of Rts 1.
An Rts1 derivative, pTW20, contains three incompatibility (inc) regions, incI-a (incI in previous studies), incII, and newly determined incI-b loci. By restriction analysis, we have located the incI-b adjacent to the incI-a region on the pTW20 map. Nucleotide sequence analysis of the minimal incI-b region revealed the presence of four repeated sequences, each consisting of 18 bp, which is similar to the incI-a and incII repeats existing on mini-Rts1. All four repeating units were required for expression of a strong incompatibility. In addition, RepA protein, essential for the replication of Rts1, bound specifically to the repeated sequences, suggesting that the repeats would titrate out RepA protein as do incI-a and IncII. Insertion of the incI-b to a mini-Rts1 plasmid in a natural arrangement decreases the copy number of mini-Rts1 to the same level as that of mini-F. The incI-a and incI-b might be a single constituent in incompatibility and copy number control of Rts1.
Nozue
H
H
Department of Bacteriology, Shinshu University School of Medicine, Matsumoto, Japan.
Tsuchiya
K
K
Kamio
Y
Y
D001483:Base Sequence; D002678:Chimera; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics*; D008969:Molecular Sequence Data; D011815:R Factors
D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes