FIG. 1.

(A) Gene organization of Tapa, a SIN cDNA. (B) 3′ sequence of the TT21qa; NS, nonstructural genes; S, structural genes; (A)n, poly(A) tail. It is important to note that linearization of TT21qa with XhoI cleaves the DNA between A and G. Therefore, the RNA transcribed from the TT21qa/Xho construct may contain 1 to 5 bases of the XhoI motif. (C) 3′ sequence of the SIN genome recovered from BHK cells transfected with TT21qa/Xho RNA. The 11 PCR products corresponding to the viral RNA (Fig. 3A) were sequenced with JC1000-1H. The size of the poly(A) tail ranged from 17 to 39 nt. All 11 virus isolates were identical with respect to the 3′ terminal 73 nt.