Figure 4.

The lactococcal CRISPR-Cas interfere with phage DNA replication; orf36 and orf53.

Migration of the total DNA extractions, obtained from phage P008-infected and non-infected L. lactis strains as well as phage P008 only, digested with SpeI and PvuII restriction enzymes. The respective strains used for the infection were L. lactis 1403S (control), L. lactis 1403S-RS36c, L. lactis 1403S-RS36n, L. lactis 1403S-RS53c, and L. lactis 1403S-RS53n. The prominent banding pattern in phage infected lanes represents replication of phage DNA over host genomic DNA as a consequence of phage infection. The 5-kb band is the pRS vector which is at higher copy than host genomic DNA and contains a single SpeI site. The time 20 minutes post phage infection was used and is indicated when applicable. NI = not infected.