In vitro expression of a chimeric coat protein gene from Grapevine Fanleaf virus (strain F 13)

The coat protein (CP) cistron of Grapevine Fanleaf virus strain F 13 (GFLV-F 13) has been located in the C-terminal region of the 122 k polyprotein encoded by the genomic RNA 2 [Serghini et al. (1990) J. Gen. Virol. 71: 1433-1441]. A chimeric CP gene of GFLV-F 13 including a short sequence corresponding to 3 restriction sites, the leader sequence of the GFLV-F 13 satellite RNA and an initiation codon was constructed. Transcripts from this construct were translated in wheat germ extract with equal efficiency to form a 56 k protein which comigrates on PAGE with the GFLV-F 13 CP and a protein of 52k. Both species react with GFLV-F 13 CP-specific antibodies. Deletions in the 5′ region of the CP gene show that the 56 k protein is initiated at the first AUG after the satellite leader and the 52 k protein at the second in-frame AUG. Transcripts with a 142 nt deletion including the two AUG codons from the 5′ end of the CP gene are not efficiently expressed in vitro, no major tanslation product being detected.