Rapid Rates of Pol II Elongation in the Drosophila Embryo

Curr Biol. 2017 May 8;27(9):1387-1391. doi: 10.1016/j.cub.2017.03.069. Epub 2017 Apr 27.


Elongation of RNA polymerase II (Pol II) is thought to be an important mechanism for regulating gene expression [1]. 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.

Keywords: Drosophila embryo; Pol II elongation; live imaging; transcription.

MeSH terms

  • Animals
  • Drosophila / embryology*
  • Drosophila / genetics*
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Embryo, Nonmammalian / cytology
  • Embryo, Nonmammalian / metabolism*
  • Female
  • Gene Expression Regulation*
  • Male
  • Promoter Regions, Genetic
  • RNA Polymerase II / genetics
  • RNA Polymerase II / metabolism*
  • Transcription Elongation, Genetic*
  • Transcription Initiation, Genetic


  • Drosophila Proteins
  • RNA Polymerase II