These results indicated that unusual viral RNA species harboring the 5′-region of (-)-sense SeV genome RNA, which was not produced during infection by IFN-β-non-inducing Z-WT, was produced in infections by IFN-β-inducing CNT and 4C(-), and were selectively formed into distinct cytoplasmic inclusions in an RNA-type-dependent manner. This evidence concerns the gene IFNB1 and infection.