Tale of the unseen phage

Lactococcal phages are among the best characterized phages of Gram-positive bacteria and as such represent excellent models to promote our understanding of phage-host interactions. In recent years, microarray technology has been employed to define the transcriptional profile of phages during infection, while simultaneously uncovering the response of the host to the infection event. The responses to infection by a lytic and a temperate phage of Lactococcus lactis were analyzed, combined with an assessment of the host response to lysogenisation with the temperate phage, Tuc2009. Here, we discuss the lessons learned from such transcriptional profiling studies, focusing on studies relating to phages of Lactococcus lactis, and how this knowledge may be applied to future studies.