A specific cis-hairpin ribozyme facilitates infection of a TMV-based DNA vector in tobacco protoplasts.

Abstract

The effect of a specific cis-hairpin ribozyme on TMV-based vectors in the infection of tobacco protoplasts was studied. Vectors contained full-length TMV genome cDNA linked to a T7 promoter or a CaMV 35S promoter at the 5'-end and an NOS gene polyadenylation signal at the 3'-end. The coat protein (CP) gene was replaced with the green fluorescent protein (GFPuv) gene allowing quantification of protoplast infection. In plasmids pTMVGFPRIB (T7-driven) and pSTMVGFPRIB (CaMV 35S-driven), the cDNA fragment of the cis-hairpin ribozyme (designed to specifically cleave the transcripts immediately downstream of the 3'-terminus of TMV RNA) was inserted between the 3'-terminus of TMV genome and NOS sequence. The in vitro transcript TMVGFPRIB was three- to fivefold more infectious than the control TMVGFPNOS. Northern blot analysis indicated that the 3'-terminal non-viral sequence had been cleaved from the in vitro transcripts by the cis-hairpin ribozyme soon after in vitro transcription. pSTMVGFPRIB and pSTMVGFPNOS plasmid DNAs were, as expected, less infectious than their in vitro transcript counterparts. However, pSTMVGFPRIB was somewhat more infectious than pSTMVGFPNOS. Northern blot analysis indicated that pSTMVGFPRIB synthesized more genomic and sub-genomic RNAs in the protoplasts. The significant increase in infectivity and viral RNA synthesis is due to the specific activity of the cis-hairpin ribozyme in vivo. Therefore, the cis-hairpin ribozyme described here may improve TMV-based vectors in the expression of foreign protein in plants.

• Authors: Ligang Wu, Jihua Fan, Lubin Jiang, Hui Wang, Rentao Song, Qingqi Zhang, Huihui Zhu, Ning Li, Zhixue Liu, Zhengkai Xu
• Journal: Journal of virological methods (J Virol Methods) Vol. 111 Issue 2 Pg. 101-9 (Aug 2003) ISSN: 0166-0934 [Print] Netherlands
• PMID: 12880925 (Publication Type: Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Luminescent Proteins
• RNA, Catalytic
• RNA, Viral
• hairpin ribozyme
• Green Fluorescent Proteins

Topics

• Base Sequence
• Genetic Vectors
• Green Fluorescent Proteins
• Luminescent Proteins (genetics, metabolism)
• Molecular Sequence Data
• Plasmids
• Protoplasts (virology)
• RNA, Catalytic (chemistry, genetics, metabolism)
• RNA, Viral (biosynthesis, genetics)
• Tobacco (virology)
• Tobacco Mosaic Virus (genetics, physiology)
• Transcription, Genetic