tokens: Domain B has been described as a B-cell-specific EB1-responsive element ( P.M.Lieberman , J.M.Hardwick , and S.D.Hayward , J.Virol.63 : 3040-3050 , 1989 ) activated synergistically by EB1 and R , an EBV early product encoded by the open reading frame BRLF1 ( M.A. Cox , J.Leahy , and J.M.Hardwick , J.Virol.64 : 313-321 , 1990 ) .