Characterization and nucleotide sequence of the orif-traM-finP region of the IncFVII plasmid pSU233

Abstract

By hybridizing the IncFVII haemolytic plasmid pSU233 with a probe containing the origin of transfer of the IncFII plasmid R1, we isolated a 1.9 kb BglII fragment containing at least the origin of transfer (oriT), and the genes traM and finP. Functional complementation analysis of deletion derivatives was used to map the origin of transfer. We also determined the nucleotide sequence of traM and finP. Comparison with similar regions of several plasmids, also belonging to the Rep-FIIA family, revelaed that pSU233 resembles the F plasmid by very close. The homology is not evenly distributed along this region, but clustered into homologous regions (TraZb-oriT, TraMb-oriT and traM separated by non-homologous regions (TraYb-oriT, finP). This organization resembles that reported for the replication region and also suggests evolution by exchange of modules. In addition, the nucleotide sequence of finP is different from those previously described for other IncF plasmids and constitutes a new allele, which we have denominated allele VI.

Analysis of the sequence and gene products of the transfer region of the F sex factor.

“…The sequence in F(I) from nt 101 (Fig. 2) to the start of the traM gene (nt 465) (243, 244) is compared with equivalent sequences in ColB4-K98 (II) (61), R1-19 (III) (62), R100 (IV) (58, 61), and pED208 (V) (48). In addition, the sequences for the onT regions of pSU233 (222), pSU316 (152), and P307 (98) are presented. The proposed nick site for the bottom strand is marked as nick (A) (173).…”

“…7). The sequences of the traM genes from pSU233, pSU316, and P307 are almost identical to that for F and contain only minor alterations (98,152,222). However, it is not known whether these genes can complement a traM mutation in F. The small number of differences at the N terminus of the first four alleles suggests that this domain is involved in binding to oriT.…”

“…Deletion and insertion analysis of the traI gene confirmed that the nicking activity is in the N-terminal domain of the protein (247). The product expressed by the traIdel29 mutant, which lacks the first (N-terminal) 14% of traI, had lost nicking activity but retained strand separation activity (218 (222), pSU316 (152), P307 (98), R100 (IV) (58), R1-19 (III) (62), ColB4-K98 (II) (61), and pED208 (V) (48). The sequences are arranged in order of their similarity to the F TraM sequence, and the notation in the figure is the same as in Fig.…”

“…Dempsey (43,45) has proposed a more complex model for R100 traJ repression based on three possible stem-loop structures. Two other variants of FinP have recently been isolated from plasmids pSU233 and P307; they also show the characteristic variation in sequence in the predicted loops (98,222).…”

Nucleotide and Amino Acid Sequences of oriT-traM-traJ-traY-traA-traL Regions and Mobilization of Virulence Plasmids of Salmonella enterica Serovars Enteritidis, Gallinarum-Pullorum, and Typhimurium

“…1 and Table 3). The putative sbi nucleotide sequence of each of the three pSVs, however, was identical to that of F plasmid (21). As to other loci, the nucleotide sequences of the two TraY binding sites, sbyC and sbyA, of pSPV were highly homologous to those of F plasmid (Table 3), whereas substantial variations could be discerned in that of pSEV and pSTV.…”