Infectious bronchitis virus nucleocapsid protein interactions with the 3' untranslated region of genomic RNA depend on uridylate bases.

Infectious bronchitis virus (IBV) is a highly contagious virus of worldwide economic concern in poultry. Infection causes respiratory disease, as well as kidney lesions, reproductive problems and gastrointestinal disfunction. The virion consists of four structural proteins: the membrane, spike, nucleocapsid (N), and the small envelope proteins. The IBV N protein, a basic, phosphorylated protein of 409 residues, is highly conserved especially within the central or middle region among IBV strains, (Williams et al, 1992).