Stability of Morphogen Gradients & Movement of Molecules

Patterning Development in the Early Embryo
Eric Wieschaus, February 5, 2009
HHMI & Molecular Biology Department, Princeton University

Lecture Overview
In my second lecture I describe experiments using EGFP tagged Bicoid to follow Bcd gradient establishment in living embryos, and to test various aspects of the simple model. Despite continuous synthesis of new Bcd protein at the anterior end of the egg, we find that the concentration of Bcd in nuclei at any given point along the anterior posterior axis is constant over time and is reproducible from embryo to the next. This reproducibility means that the gradient is sufficiently robust to provide positional information and thus can accurately direct gene activities. One the other hand, quantitative imaging experiments point to several features of the gradient that are hard to explain - how target genes activated by Bcd distinguish relatively subtle differences in low concentrations, and how Bcd molecules move from the anterior site of their synthesis to the site of their transcriptional activity.
Part 2: Stability of Morphogen Gradients & Movement of Molecules

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Part 1: Where does pattern come from?

Part 3: Evolution of Bicoid-based Patterning in the Diptera

Speaker Bio    Related Articles

Lecture Overview In my second lecture I describe experiments using EGFP tagged Bicoid to follow Bcd gradient establishment in living embryos, and to test various aspects of the simple model. Despite continuous synthesis of new Bcd protein at the anterior end of the egg, we find that the concentration of Bcd in nuclei at any given point along the anterior posterior axis is constant over time and is reproducible from embryo to the next. This reproducibility means that the gradient is sufficiently robust to provide positional information and thus can accurately direct gene activities. One the other hand, quantitative imaging experiments point to several features of the gradient that are hard to explain - how target genes activated by Bcd distinguish relatively subtle differences in low concentrations, and how Bcd molecules move from the anterior site of their synthesis to the site of their transcriptional activity.	Part 2: Stability of Morphogen Gradients & Movement of Molecules Click image above to start seminar in 320x240 format Click here to view in larger 640x480 format* QuickTime 7 Required * System Requirements (there may be a few seconds delay before seminars start) Downloads in alternative formats: (To Save, Right Click a link below and select "Save Target/Link As") QuickTime MP4 iPod/iPhone Video PowerPoint Slides Format Descriptions Download Accelerator/Resume Broken Downloads Software
Part 1: Where does pattern come from? Part 3: Evolution of Bicoid-based Patterning in the Diptera Speaker Bio Related Articles