Characterization of an open reading frame involved in site-specific integration of filamentous phage Cf1t from Xanthomonas campestris pv. citri.

Cf1t is a single-stranded DNA filamentous phage; a 1.9-kb segment of DNA from Cf1t was found to be responsible for site-specific integration into Xanthomonas campestris pv. citri (XW47), in the absence of any Xanthomonas origin of replication. Deletion analysis and introduction of amber stop codons into this fragment from Cf1t revealed an open reading frame (ORF344) which was involved in the integration function. The predicted amino-acid sequence of ORF344 bears no homology with conserved sequences of the integrase family.