The Bicoid gradient is shaped independently of nuclei.
Publication Year
2010
Type
Journal Article
Abstract
Morphogen gradients provide embryos with positional information, yet how they form is not understood. Binding of the morphogen to receptors could affect the formation of the morphogen gradient, in particular if the number of morphogen binding sites changes with time. For morphogens that function as transcription factors, the final distribution can be heavily influenced by the number of nuclear binding sites. Here, we have addressed the role of the increasing number of nuclei during the formation of the Bicoid gradient in embryos of Drosophila melanogaster. Deletion of a short stretch of sequence in Bicoid impairs its nuclear accumulation. This effect is due to a approximately 4-fold decrease in nuclear import rate and a approximately 2-fold reduction in nuclear residence time compared with the wild-type protein. Surprisingly, the shape of the resulting anterior-posterior gradient as well as the centre-surface distribution are indistinguishable from those of the normal gradient. This suggests that nuclei do not shape the Bicoid gradient but instead function solely during its interpretation.
Keywords
Journal
Development
Volume
137
Issue
17
Pages
2857-62
Date Published
09/2010
ISSN Number
1477-9129
Alternate Journal
Development
PMID
20699297