bicoid bcd mRNA gradient formation in Drosophila

WATCH THIS VIDEO IN 720 p HD! See also: Formation of the bicoid morphogen gradient: an mRNA gradient dictates the protein gradient. Development 136, 605-614 (2009).
The Bicoid (Bcd) protein gradient is generally believed to be established in pre-blastoderm Drosophila embryos by the diffusion of Bcd protein after translation of maternal mRNA, which serves as a strictly localized source of Bcd at the anterior pole. However, previous reports showed that the Bcd gradient is preceded by a bcd mRNA gradient. These early observations were revisited and extended. The results demonstrate that the bcd mRNA and Bcd protein gradient profiles are virtually identical at all times. This confirms the previous conclusion that the Bcd gradient is produced by a bcd mRNA gradient rather than by diffusion. Based on the observation that bcd mRNA colocalizes with Staufen (Stau), it is proposed that the bcd mRNA gradient forms by a novel mechanism involving quasi-random active transport of a Stau-bcd mRNA complex through a nonpolar microtubular network, which confines the bcd mRNA to the cortex of the embryo.
Check also: http://www.med.lu.se/expmed/developmental_biology

Category:

Science & Technology

Tags:

• bicoid bcd mRNA gradient
• ARTS model
• Staufen
• microtubules
• active mRNA transport
• morphogenetic gradient
• Drosophila