The genome and structural proteome of YuA, a new Pseudomonas aeruginosa phage resembling M6

Division of Gene Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 21, Leuven, B-3001, Belgium; Shemyakin-Ovchinnikov, Institute of Bioorganic Chemistry, Miklukho-Maklaya, Street 6/10, Moscow 117997, Russia; Biomedical Research Institute, Limburgs Universitair Centrum and School of Life Sciences, University Hasselt, Diepenbeek, B-3590, Belgium

^* To whom correspondence should be addressed. Email: kirsten.hertveldt{at}biw.kuleuven.be.

	Abstract

Pseudomonas aeruginosa phage YuA was isolated from a pond near Moscow. It has an elongated head, encapsulating a circularly permuted genome of 58,663 bp, and a flexible, non-contractile tail which is terminally and subterminally decorated with short fibers (Siphoviridae). The YuA genome is neither Mu nor -like, and encodes 78 gene products that cluster in three major regions involved in (1) DNA metabolism and replication, (2) host interaction and (3) phage particle formation and host lysis. At the protein level, YuA displays significant homology with phages M6, JL001, 73, B3, DMS3 and D3112. Eighteen YuA proteins were identified as part of the phage particle by mass spectrometry analysis. Five different bacterial promoters were experimentally identified using a promoter trap assay, three of which have a ⁵⁴-specific binding site and regulate transcription in the genome region involved in phage particle formation and host lysis. The dependency of these promoters for the host ⁵⁴ factor was confirmed by analysis in an rpoN mutant strain of P. aeruginosa PAO1. At the DNA level, YuA is 91% identical to the recently (July 2007) annotated phage M6 of the Lindberg Typing set. Despite this level of DNA homology throughout the genome, both phages combined have 15 unique genes that do not occur in the other phage. The genome organization of both phages differs substantially from the other known Pseudomonas-infecting Siphoviridae, delineating them as a distinct genus within this family.