14-653 Sigma-AldrichEphA1 Protein, active, 10 µg

The control of cell movement during development is essential for forming and stabilizing the spatial organization of tissues and cell types. During initial steps of tissue patterning, distinct regional domains or cell types arise at appropriate locations, and the movement of cells is constrained in order to maintain spatial relationships during growth. In other situations, the guidance of migrating cells or neuronal growth cones to specific destinations underlies the establishment or remodeling of a pattern. Eph receptor tyrosine kinases and their ephrin ligands are key players in controlling these cell movements in many tissues and at multiple stages of patterning.

Some receptor tyrosine kinase genes are mutated in inherited and somatically acquired human cancers. To permit mutational analysis, the complete genomic structure of the human EPHA1 gene on chromosome 7q34 was determined and oligonucleotide pairs were designed to amplify coding regions. The gene contains 18 exons, two more than the related tyrosine kinase, EPHB2. Presumed sequencing errors in the published cDNA sequence of EPHA1 were identified in exons 10 and 11. Availability of this information will facilitate mutational analysis of EPHA1.

The Eph receptors are the largest known family of receptor tyrosine kinases. Initially all of them were identified as orphan receptors without known ligands, and their specific functions were not well understood. During the past few years, a corresponding family of ligands has been identified, called the ephrins, and specific functions have now been identified in neural development. The ephrins and Eph receptors are implicated as positional labels that may guide the development of neural topographic maps. They have also been implicated in pathway selection by axons, the guidance of cell migration, and the establishment of regional pattern in the nervous system. The ligands are anchored to cell surfaces, and most of the functions so far identified can be interpreted as precise guidance of cell or axon movement. This large family of ligands and receptors may make a major contribution to the accurate spatial patterning of connections and cell position in the nervous system.