Integration of the DNA of filamentous bacteriophage Cflt into the chromosomal DNA of its host

Abstract

It was demonstrated for the first time that filamentous bacteriophage Cflt, which contains single-stranded DNA, can incorporate its genome into that of its host. Evidence in support of the incorporation was obtained from a Southern blot hybridization analysis of DNA isolated from Cflt-lysogenized cells. DNAs from different Cflt-lysogenized cells were purified, and the integration patterns were compared. Because all integration patterns were identical and only one fragment in Cflt replicative-form DNA was missing, it appears that the integration was site specific. Only one complement of viral DNA was integrated per host chromosome. To determine the attachment site on the viral DNA, the physical map of EcoRI, XhoI, SstII, and BglII on Cflt DNA was constructed. Based on this physical map and a Southern blot hybridization analysis of lysogen DNA with these restriction endonucleases, we demonstrated that DNA sequences from all regions of the Cflt genome were represented in the integrated viral sequences. The attachment site on the viral genome was located at 69.2 to 73.8 min on the Cflt DNA.

Filamentous phages: masters of a microbial sharing economy

“…Other Xanthomonas phages, Cf, Cf1t/Cf1c and Cf16, were isolated from the citrus canker pathogen Xanthomonas citri in the 1980s. Cf1c was the first discovered example of a filamentous phage integrating into the host genome . The Lf phage was later isolated from cruciferous vegetable black rot pathogen Xanthomonas campestris and was used as a cloning vehicle for the integration of DNA into X. campestris .…”

The packaging signal ofXanthomonasintegrative filamentous phages

“…Unlike Escherichia coli Ff phages (f1, fd, M13, etc.) that replicate as episomes, all Xanthomonas filamentous phages are often lysogenized by the integration of their genomes into the host bacterial chromosomes, where they replicate as prophages (Kuo et al, 1987a;Kuo et al, 1987b;Dai et al, 1987;Dai, et al, 1988;Bai, 1989;Fu et al, 1992;Lin et al, 1994;Kamiunten, 1995;Ahmad et al, 2014;Yeh, 2017;Yeh, 2020). Cf (Cflt and Cf16) is the first "integrative" filamentous phage reported (Kuo et al, 1987a;Kuo et al, 1987b;Dai et al, 1987).…”

Complete nucleotide sequence of filamentous phage Cf1c fromXanthomonas campestrispv.citri

“…Cflt is a small virus and contains a positive single stranded DNA molecule, which, upon infection, is converted into a double stranded replicative form of 7,308 base pairs in length. The DNA is encapsulated in a long protein coat (1,2). This phage forms a turbid plaque, does not greatly affect the growth of the host cell, and integrates its viral DNA into the host chromosome and undergoes a lysogenic cycle.…”