First, the DNA substrate is processed by proteins that assemble around the DNA at a conserved DNA sequence, the origin-of-transfer (OriT), forming a complex called the relaxosome.
This approach could be further extended to take into account knowledge of likely origins of transferred genes, particularly low-G + C prophage sequences, by mining the rapidly growing set of sequenced genomes (including bacteriophage genomes) for information about frequent exchange partners (Beiko et al. 2005; Dagan et al. 2008).
For example, a genome-wide analysis revealed that 755 out of 4,288 genes have been transferred to the Escherichia coli genome, and at least 234 HGT events contributed to the origin of these transferred genes [ 4].
To express inserted genes using Streptomyces species as the production hosts, an integration expression cassette is required to be inserted into the BAC vector, which includes genetic elements encoding a phage-specific attachment site, an integrase, an origin of transfer, a selection marker and a promoter.
This transfer process is initiated by nicking DNA and finished by religation at the origin of transfer (oriT) resulting in a monomeric circle of transferred DNA.
The origin of transfer (oriT), including the nic site is in plasmids of the IncP family located between these two operons [35].
Similar to other F plasmids, the tra region in pAPEC-1 is boarded by the origin of transfer (oriT) and the fertility inhibition gene, finO [[31]; Fig. 3A].
Within the same contig, an origin of transfer (oriT) was identified based on the 99% similarity (expect = 0.0) to the mobilization region of pAD1 where an oriT has been previously identified between ORF53 and ORF57 (AF343837) [24].
We were unable to identify a region in pBJS-O resembling a known plasmid origin of transfer.
Also, we were unable to identify a region in pBJS-O resembling a known plasmid origin of transfer.
