RT Journal Article
SR Electronic
T1 A Facilitated Diffusion Mechanism Establishes the Drosophila Dorsal Gradient
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 057091
DO 10.1101/057091
A1 Sophia N. Carrell
A1 Michael D. O’Connell
A1 Amy E. Allen
A1 Stephanie M. Smith
A1 Gregory T. Reeves
YR 2016
UL http://biorxiv.org/content/early/2016/06/03/057091.abstract
AB The transcription factor NF-κB plays an important role in the immune system as an apoptotic and inflammatory factor. In the Drosophila melanogaster embryo, a homolog of NF-ΚB called Dorsal (dl) patterns the dorsal-ventral (DV) axis in a concentration-dependent manner. During early development, dl is sequestered outside the nucleus by Cactus (Cact), homologous to IκB. Toll signaling at the ventral midline breaks the dl/Cact complex, allowing dl to enter the nucleus where it transcribes target genes. Here we show that dl accumulates on the ventral side of the embryo over the last 5 cleavage cycles and that this accumulation is the result of facilitated diffusion of dl/Cact complex. We speculate that the predominant role for Cact in DV axis specification is to shuttle dl towards the ventral midline. Given that this mechanism has been found in other, independent systems, we suggest it may be more prevalent than previously thought.