Enterobacteria phage P4
Enterobacteria phage P4 (also known as satellite phage P4) is a temperate bacteriophage strain of species Escherichia virus P2 within genus Peduovirus (formerly P2-like viruses, P2virus, and P2likevirus), subfamily Peduovirinae, family Myoviridae. It is a satellite virus, requiring P2-related helper phage to grow lytically.

Structure
The P4 virion has a tail and an icosahedral head containing a linear double-stranded DNA genome of 11,627 kb.

Life cycle
Phage P4 infects Escherichia coli. It is a satellite virus which cannot engage in lytic growth without the presence of a P2-related helper phage. It generally follows a lysogenic life cycle: after infection, the P4 genome integrates into that of its host.  The P4 genome can also exist on its own within the host cell and can replicate as a free plasmid.

References

External links
NCBI Taxonomy

Myoviridae
Satellite viruses