M. Mori et al., EFFICIENT PRODUCTION OF HUMAN GAMMA-INTERFERON IN TOBACCO PROTOPLASTSBY GENETICALLY-ENGINEERED BROME MOSAIC-VIRUS RNAS, Journal of General Virology, 74, 1993, pp. 1255-1260
We succeeded in producing human gamma interferon (IFN-gamma) in tobacc
o protoplasts in quantity using genetically engineered brome mosaic vi
rus (BMV strain ATCC66). This strain of BMV produces two types of coat
protein, a full-length coat protein (20K) and a truncated coat protei
n (19K) which are translated from the first and second initiation codo
ns, respectively. We replaced the truncated coat protein gene with the
IFN-gamma gene and synthesized BMV-IFN-gamma chimera RNAs using an in
vitro transcription system. The BMV-IFN-gamma chimera RNAs were used
to inoculate tobacco protoplasts together with BMV RNA 1 and RNA 2 and
produced IFN-gamma to a level of 5 to 10 % of total extracted protein
s per infected protoplast after 24 h of incubation. The efficient prod
uction of IFN-gamma was attributed to the high translation activity of
the BMV-IFN-gamma chimera RNA. We demonstrate that 24 nucleotides cod
ing for the N-terminal amino acids of the full-length coat protein wer
e probably involved in the high translation activity of the BMV-IFN-ga
mma chimera RNA.