A novel expression system based on coinfection of cells with two recombinant vaccinia viruses has been developed. One recombinant vaccinia virus contained the bacteriophage T7 RNA polymerase gene under control of a vaccinia virus promoter. The second recombinant vaccinia virus contained a target gene of choice flanked by bacteriophage T7 promoter and termination sequences. Maximum expression of...

Tagetitoxin, a chlorosis-inducing phytotoxin produced by Pseudomonas syringae pv. tagetis, inhibits RNA synthesis directed by chloroplast RNA polymerase. In isolated chloroplasts, tagetitoxin quickly and specifically reduced the incorporation of [‘HJuridine into RNA. When it was added to transcriptionally active chloroplast protein extracts, the toxin directly inhibited incorporation of [32P]UT...

DNA-directed RNA polymerases are capable of initiating synthesis of RNA without primers, the first catalytic stage of initiation is referred to as de novo RNA synthesis. De novo synthesis is a unique phase in the transcription cycle where the RNA polymerase binds two nucleotides rather than a nascent RNA polymer and a single nucleotide. For bacteriophage T7 RNA polymerase, transcription begins ...

The T7 RNA polymerase-dependent transcription was studied as a function of nucleotide sequence structures positioned upstream of the T7 promoter. Model double-stranded DNA templates were constructed for this purpose. They contained a target sequence of 485 base pairs (cDNA fragment of Venesuelian encephalomyelitis equine virus genome), T7 promoter consensus and different extra base sequences up...

To make messenger RNA transcripts, bacteriophage T7 RNA polymerase (T7 RNAP) undergoes a transition from an initiation phase, which only makes short RNA fragments, to a stable elongation phase. We have determined at 2.1 angstrom resolution the crystal structure of a T7 RNAP elongation complex with 30 base pairs of duplex DNA containing a "transcription bubble" interacting with a 17-nucleotide R...

In vitro transcription with T7 RNA polymerase is one of the most powerful tools in RNA research+ This is mainly linked to the easy preparation of the enzyme, the quite unlimited range of sizes and sequences of the RNA that can be synthesized, as well as the efficiency and accuracy of synthesis+ So far only two major limitations are common knowledge, namely poor transcription efficiency of non-G...

We have developed plant virus-based vectors for virus-induced gene silencing (VIGS) and protein expression, based on Alternanthera mosaic virus (AltMV), for infection of a wide range of host plants including Nicotiana benthamiana and Arabidopsis thaliana by either mechanical inoculation of in vitro transcripts or via agroinfiltration. In vivo transcripts produced by co-agroinfiltration of bacte...