A primer on the development and anatomy of the motor axon system
in the Drosophilaembryo.


Images and web pages constructed by Kai Zinn (zinnk@its.caltech.edu)

Embryos stained and dissected by Chand Desai (desai@seqaxp.caltech.edu)

This primer consists of a set of Adobe Photoshop images, each with accompanying text, and a few diagrams. Most of the images in the current version are of wild-type embryos stained with the 1D4 antibody against Fasciclin II, which specifically labels motor axons (Van Vactor et al., Cell 73, 1137-1153 (1993)). The same segments are shown in several focal planes, so that the viewer can see the details of the pathways as if they were examining an actual embryo under the microscope. There are also embryos double-stained for PNS, muscle, and tracheal markers, so that motor axon development can be keyed to the development of other structures. In future versions we plan to include galleries of images from mutant embryos, images of wild-type embryos double-stained for additional markers, and images of motor axon development in other insect species.

The primer has several interlocking purposes: 1) to serve as a teaching resource for new members of groups working on genes involved in neuromuscular system development; 2) to provide a source of detailed information on the wild-type pattern of development for groups not currently working on this system who wish to determine whether their mutants might have effects on motor axon guidance. Since only a few images of wild-type embryos can be included in any paper describing a motor axon guidance phenotype, it is time-consuming for people unfamiliar with the system to determine whether a subtle phenotype observed in 1D4-stained embryos is real; 3) to provide galleries of images of mutant phenotypes, so that new phenotypes can be compared in detail to existing phenotypes without the necessity of obtaining all of the mutant stocks and staining them in one's own laboratory.

We envision that this primer will become linked to collections of images of the development of other embryonic, larval, and pupal structures that have been or will be assembled by other groups. We have begun this process by linking the current primer to other resources that we know of, such as the Chris Doe group's neuroblast map. We welcome any information on other links that we should add. Please send comments, criticisms, and corrections to K. Zinn at the above e-mail address.

Organization of the primer, and how to use it. Click this link next!

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