Synthetic reconstruction of the hunchback promoter specifies the role of Bicoid, Zelda and Hunchback in the dynamics of its transcription
Fernandes, Gonçalo; Tran, Huy; Andrieu, Maxime; Diaw, Youssoupha; Romero, Carmina Perez; Fradin, Cécile; Coppey, Mathieu; Walczak, Aleksandra M.; Dostatni, Nathalie (2022-04)
Fernandes, Gonçalo
Tran, Huy
Andrieu, Maxime
Diaw, Youssoupha
Romero, Carmina Perez
Fradin, Cécile
Coppey, Mathieu
Walczak, Aleksandra M.
Dostatni, Nathalie
04 / 2022
e74509
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202210037395
https://urn.fi/URN:NBN:fi:tuni-202210037395
Kuvaus
Peer reviewed
Tiivistelmä
For over 40 years, the Bicoid-hunchback (Bcd-hb) system in the fruit fly embryo has been used as a model to study how positional information in morphogen concentration gradients is robustly translated into step-like responses. A body of quantitative comparisons between theory and experiment have since questioned the initial paradigm that the sharp hb transcription pattern emerges solely from diffusive biochemical interactions between the Bicoid transcription factor and the gene promoter region. Several alternative mechanisms have been proposed, such as additional sources of positional information, positive feedback from Hb proteins or out-of-equilibrium transcription activation. By using the MS2-MCP RNA-tagging system and analysing in real time, the transcription dynamics of synthetic reporters for Bicoid and/or its two partners Zelda and Hunchback, we show that all the early hb expression pattern features and temporal dynamics are compatible with an equilibrium model with a short decay length Bicoid activity gradient as a sole source of positional information. Meanwhile, Bicoid’s partners speed-up the process by different means: Zelda lowers the Bicoid concentration threshold required for transcriptional activation while Hunchback reduces burstiness and increases the polymerase firing rate.
Kokoelmat
- TUNICRIS-julkaisut [19236]