Chapter 03

Patterning the vertebrate body plan I: axes and germ layers

Vertebrate life cycles and outlines of development

http://worms.zoology.wisc.edu/frogs/welcome.html
Frogs and other amphibians will figure prominently in your studies of developmental biology. What are some of the advantages of studying development in this amphibian model organism? The Amphibian Embryology Tutorial at Jeff Hardin's Dynamics of Development site will guide you through the highlights of this model organism. Explore the site and correlate the information you find online with the topics in your book (Chapter 3 and 4 in Wolpert text). Find all of the animations and movies. How many can you find? List them, along with the figure from the text which shows a static view of the same process.

Model Organism Databases:

http://embryology.med.unsw.edu.au/
This Embryology site from Mark Hill at the University of New South Wales takes you through a tour of the dynamic nature of development in a variety of model organisms, including details on normal and abnormal human embryo development.

http://www.chicken-genome.org/
This site, hosted by the Roslin Institute, is a great place to begin learning more about how the chicken genome project has shaped progress in the field of chicken development.

http://www.sdbonline.org/archive/dbcinema/
The Developmental Biology Cinema features quail-chick chimeras, first developed by Nicole Le Douarin (see also page 286 Wolpert text). Could you reproduce these manipulations in your laboratory?

http://www.xenbase.org/
XenBase contains a wealth of resources for Xenopus laevis genomics, embryology and laboratory techniques. Follow the “Anatomy and Development” tabs to visit the digitized images and developmental data from Nieuwkoop and Faber Normal Table of Xenopus laevis , or the archives of images and animations. For a truly interactive experience, click on the cell fate maps (based on the work of Sally Moody) for a dynamic look at fate of individual blastomeres in the frog embryo. If you were to inject dye into blastomere b1 in the 32 cell stage frog embryo what major systems would retain the dye? Conversely, use the “reverse map” to identify the blastomeres that give rise to the lens. (Page 92 Wolpert text)

http://zfin.org
ZFIN, the zebrafish model organism resource for genomics and development includes digitized images and detailed descriptions of developmental stages modified from Kimmel et al., 1995. Follow the links to an electronic version of Monte Westerfield’s The Zebrafish Book a comprehensive guide to laboratory protocols for zebrafish. (Page 96 Wolpert text)

http://genex.hgu.mrc.ac.uk/
EMAP, the Edinburgh Mouse Atlas Project includes a gene expression database and a three dimensional embryo anatomy atlas and movies. Download the mouse staging wall chart and post it in your lab. (Page 104 Wolpert text)

http://www.sdbonline.org/
The Society for Developmental Biology contains a wealth of resources for researchers and students alike. For fun you can visit the “Gallery” to view remarkable images from a diverse array of model organisms. Once there, follow the links to the laboratories that produced these images and learn more about their research.

Setting up the body axes

http://worms.zoology.wisc.edu/embryology_main.html
This Embryology Tutorial from Jeff Hardin walks you through the stages of frog development with images and movies. View the cortical rotation sequences (f. 3.28 Wolpert text) and learn how UV irradiation alters this essential step in early development. How could you reproduce this experiment in your laboratory? For some added fun, view the video clip of frogs in space on the Space Shuttle.

http://www.ncbi.nlm.nih.gov/
Members of the "TGF-ß" family of signaling molecules play a crucial role in early patterning events ( Box 3C Wolpert text). What is TGF-ß? After answering this question learn more about its role in human development, physiology, and disease. Go to the NCBI’s Online Mendelian Inheritance in Man database (OMIM) and search for "tgfb". Report on TGF-ß and its role in a variety of diseases.

http://www.biocarta.com/pathfiles/wntPathway.asp
Signaling molecules of the "wnt" family are important in dorsal-ventral axis formation in both frogs and flies. In flies, the "wnt signaling pathway" acts through ß-catenin. ß-catenin appears to be important in frogs, too, in being a critical determinant of the Nieuwkoop center. Although the role of wnt signaling in establishing the Nieuwkoop center is still unclear, Xwnt-11 is found in the vegetal hemisphere along with Vg-1, and can rescue axis formation in UV-irradiated eggs. Review the wnt resources at Biocarta and page 110-114 Wolpert text. To demonstrate your understanding of this pathway design a set of experiments that would test the role of wnt signaling as the key event resulting from cortical rotation:

Oxford University Press, Online Resource Centre, Chapter 03.

Chapter 03

Patterning the vertebrate body plan I: axes and germ layers