This family consists of several Rotavirus specific VP3 proteins. VP3 is known to be a viral guanylyltransferase and is thought to posses methyltransferase activity and therefore VP3 is a predicted multifunctional capping enzyme [1].
Chen D, Luongo CL, Nibert ML, Patton JT.
Rotavirus open cores catalyze 5'-capping and methylation of exogenous RNA: evidence that VP3 is a methyltransferase.
Virology 265 120-30 1999
[PubMed: 10603323] http://dx.doi.org/10.1006/viro.1999.0029