Measurements of RNA chain growth rates are often led astray by the phenomenon of
ID: 69723 • Letter: M
Question
Measurements of RNA chain growth rates are often led astray by the phenomenon of pausing, in which an RNA polymerase molecule stops transcription when it reaches certain sites, for intervals that may be as long as several seconds.
How might pausing be detected?
a. separation of labeled mRNA by centrifugation in CsCl gradient after transcription in vivo with radiolabeled nucleotides
b. hybridization of labeled fluorescent probes of cDNA with the cell DNA in situ
c. gel electrophoresis and autoradiography labeled RNA products after transcription in vitro with radiolabeled nucleotides
d. microscopy analysis of labeled RNA after transcription in vitro with fluorophores
Explanation / Answer
c. Gel electrophoresis and autoradiography labeled RNA products after transcription in vitro with radiolabeled nucleotides.
After the experiment, each sample of the pause are subjected to electrophoresis. Autordiogram of the experiment is then analyzed, the distribution of each of the transcript species is measured as percentrage total molecules.