The insertion site of the temperate phage HB-746 is located near the phage remnant in the pneumococcal host chromosome.

Combined Southern blot hybridization analyses of DNA digests of several clinical strains of Streptococcus pneumoniae have revealed the presence of a gene (hblR), or part of it, similar to the hbl7 gene coding for the cell wall lytic enzyme of the temperate HB-746 phage. The results confirmed that the genome of HB-746, which contains protein covalently linked to the 5' ends of its DNA, becomes integrated into the host strain 8R1 and showed that both the host and phage attachment sites, attB and attP, lie downstream of the 3' end of the structural region of the hblR and hbl7 genes, respectively. The data reported also highlight some evolutionary relationships between phage and bacteria.