Riboprobes are RNA probes that can be produced by in vitro

In vitro

In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...

transcription of cloned DNA inserted in a suitable plasmid

Plasmid

In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular...

 downstream of a viral promoter. Some bacterial viruses code for their own RNA polymerase

RNA polymerase

RNA polymerase is an enzyme that produces RNA. In cells, RNAP is needed for constructing RNA chains from DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses...

s, which are highly specific for the viral promoters. Using these enzymes, labeled NTP

Nucleoside triphosphate

Nucleoside triphosphate is a nucleoside with three phosphates. Natural nucleoside triphosphates include adenosine triphosphate , guanosine triphosphate , cytidine triphosphate , 5-methyluridine triphosphate , and uridine triphosphate . These terms refer to those nucleoside triphosphates that...

s, and inserts inserted in both forward and reverse orientations, both sense and antisense riboprobes can be generated from a cloned gene.