First published online November 9, 2007
Development 134, 2303e (2007)
© The Company of Biologists Limited
Nuclear ins and outs of Dorsal gradients
The dorsoventral axis of the Drosophila embryo is specified by a
ventral-to-dorsal concentration gradient of the NF-
B/REL transcription
factor Dorsal in the nuclei of the syncitial embryo. This gradient's formation
involves the nuclear import of cytoplasmic Dorsal in response to an
extracellular signal. Now, Robert DeLotto and colleagues report that the
maintenance of the gradient is actually a dynamic process that also involves
the Exportin 1-mediated nuclear export of Dorsal (see
p. 4233). Using
real-time, live imaging of embryos that express a Dorsal-GFP fusion protein,
the researchers show that nuclear Dorsal concentrations change continuously
during interphase and that the Dorsal gradient breaks down and reforms with
every mitotic division. Dorsal, they report, constantly shuttles in and out of
the nuclei during interphase. Furthermore, its diffusion is partly constrained
to cytoplasmic domains around each syncitial nucleus. The researchers propose,
therefore, that the generation and maintenance of the Dorsal gradient during
fly embryogenesis involves both restricted long-range diffusion and the
regulated nucleocytoplasmic shuttling of Dorsal.
Related articles in Development:
- Nucleocytoplasmic shuttling mediates the dynamic maintenance of nuclear Dorsal levels during Drosophila embryogenesis
- Robert DeLotto, Yvonne DeLotto, Ruth Steward, and Jennifer Lippincott-Schwartz
Development 2007 134: 4233-4241.
[Abstract]
[Full Text]
