Researchers from the University of California, San Diego, have discovered that certain jumbo phages construct a separating compartment around their DNA soon after it enters its host. This shield, made of a single type of protein called chimallin, allows molecules to pass through tiny pores, protecting the phage’s genome from the outside world. This remarkable example of convergent evolution is similar to the nuclear pore in eukaryotes but simpler in design. The shield can also grow as the phage’s genome replicates, physically preventing the bacteria’s CRISPR ‘immune system’ and other defensive enzymes from accessing the phage’s genetic material.
Protective Shield and Convergent Evolution
The researchers have found that this protective shield, made of a single type of protein called chimallin, is a remarkable example of convergent evolution. It is similar to the nuclear pore in eukaryotes but simpler in design. This shield allows molecules to pass through tiny pores, protecting the phage’s genome from the outside world.
Growth and Defense Mechanisms
The shield can also grow as the phage’s genome replicates, physically preventing the bacteria’s CRISPR ‘immune system’ and other defensive enzymes from accessing the phage’s genetic material.