FIG. 1.

Genome organization and cleavage map of FCV. The RNA genome of the Urbana strain of FCV is 7,683 nt in length, excluding the poly(A) tail, and is organized into ORF1 (nt 20 to 5311), ORF2 (nt 5314 to 7320), and ORF3 (nt 7317 to 7637). The proteolytic cleavage sites recognized by the virus-encoded proteinase that define the borders of the nonstructural proteins (encoded in ORF1) and the mature capsid protein (encoded in ORF2) are indicated (36a, 38). Cleavage site abbreviations are as follows: E, glutamic acid; A, alanine; D, aspartic acid; N, asparagine; and S, serine. Two major species of polyadenylated RNAs have been observed in infected cells that correspond to the full-length genome and the 3′-terminal end of the genome (7, 17, 30). The location of the region in the genome (nt 5686 to 5987) from which the sense and antisense RNA transcript probes were designed for Northern blot assays is indicated.