Genetic analysis of a Drosophila neural cell adhesion molecule: interaction of fasciclin I and Abelson tyrosine kinase mutations |
| |
Authors: | T Elkins K Zinn L McAllister F M Hoffmann C S Goodman |
| |
Institution: | Howard Hughes Medical Institute, University of California, Berkeley 94720. |
| |
Abstract: | Drosophila fasciclin I is a homophilic cell adhesion molecule expressed in the developing embryo on the surface of a subset of fasciculating CNS axons, all PNS axons, and some nonneuronal cells. We have identified protein-null mutations in the fasciclin I (fas I) gene, and show that these mutants are viable and do not display gross defects in nervous system morphogenesis. The Drosophila Abelson (abl) proto-oncogene homolog encodes a cytoplasmic tyrosine kinase that is expressed during embryogenesis primarily in developing CNS axons; abl mutants show no gross defects in CNS morphogenesis. However, embryos doubly mutant for fas I and abl display major defects in CNS axon pathways, particularly in the commissural tracts where expression of these two proteins normally overlaps. The double mutant shows a clear defect in growth cone guidance; for example, the RP1 growth cone (normally fas I positive) does not follow its normal path across the commissure. |
| |
Keywords: | |
|
|