B2 is expressed by the insect Flock House virus (FHV) as a counter-defense mechanism against antiviral RNA silencing during infection. In vitro, B2 binds to dsRNA as a dimer and inhibits the cleavage of it by Dicer. B2 blocks cleavage of the FHV genome by Dicer and also the incorporation of FHV small interfering RNAs into the RNA-induced silencing complex.
Jiyao W et al.(2023). "The conserved domain database in 2023.",