Elongation of RNA polymerase II (Pol II) is thought to be an important mechanism for regulating gene expression . We measured the first wave of de novo transcription in living Drosophila embryos using dual-fluorescence detection of nascent transcripts containing 5′ MS2 and 3′ PP7 RNA stem loops. Pol II elongation rates of 2.4–3.0 kb/min were observed, approximately twice as fast as earlier estimates [2–6]. The revised rates permit substantial levels of zygotic gene activity prior to the mid-blastula transition. We also provide evidence that variable rates of elongation are not a significant source of differential gene activity, suggesting that transcription initiation and Pol II release are the key determinants of gene control in development.
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Agricultural and Biological Sciences(all)
- Drosophila embryo
- Pol II elongation
- live imaging