Viruses related to crAssphage, a bacteriophage discovered by us in 2014, are abundant in the intestinal tract of humans around the world. We computationally predicted that crAss-like phages infect Bacteroidetes hosts and this was confirmed when the virus was recently cultured. Strikingly, amplification of the virus did not impair the host, but the molecular mechanisms involved remain unknown because the proteins involved in host interaction remain unknown. ESR 13 will focus on identifying host-interaction proteins in crAssphage. We recently discovered that crAss-like phages have been genomically co-linear for millions of years yet encode different proteins in similar genomic contexts.
Significant host-association proteins will be validated at the KU Leuven viromics group by exploiting available human and insect-associated viromes (ESR 11). Thus, we will exploit signals from fundamental processes in genome evolution to predict host-interaction proteins and further our understanding of virus-host interactions.