Friedrich Bonhoeffer

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The results of previous in vitro experiments indicate that a glycosylphosphatidylinositol (GPI)-anchored protein may play an important role in the guidance of temporal retinal axons during the formation of the topographically ordered retinotectal projection. We have purified and cloned a GPI-anchored, 25 kDa glycoprotein that is a good candidate for a(More)
In order to test the preference of growing axons for membrane-associated positional specificity a new in vitro assay was developed. In this assay, membrane fragments of two different sources are arranged as a carpet of very narrow alternating strips. Axons growing on such striped carpets are simultaneously confronted with the two substrates at the stripe(More)
Carbocyanine dyes, fluorescent lipophilic substances used for optical recordings of membrane voltage and for studies of membrane fluidity, have recently been shown to provide intense and long-lasting staining of neurones in vivo and in vitro (Schwartz & Agranoff, 1981; Honig & Hume, 1985, 1986; Catsicas, Thanos & Clarke, 1986; Landmesser & Honig, 1986;(More)
Lectin affinity chromatography combined with mAb production was used to identify chick neural cell surface molecules related to L1 antigen, a mouse neural glycoprotein implicated in cell-cell adhesion (Rathjen, F. G., and M. Schachner, 1984, EMBO (Eur. Mol. Biol. Organ.) J., 3:1-10). A glycoprotein, G4 antigen, isolated by mAb G4 from adult chick brain is(More)
Two ligands for Eph-related receptor tyrosine kinases, RAGS and ELF-1, have been implicated in the control of development of the retinotectal projection. Both molecules are expressed in overlapping gradients in the tectum, the target area of retinal ganglion cell axons. In two in vitro assays ELF-1 is shown to have a repellent axon guidance function for(More)
As growing retinotectal axons navigate from the eye to the tectum, they sense guidance molecules distributed along the optic pathway. Mutations in the zebrafish astray gene severely disrupt retinal axon guidance, causing anterior-posterior pathfinding defects, excessive midline crossing, and defasciculation of the retinal projection. Eye transplantation(More)
We have isolated mutants in the zebrafish Danio rerio that have defects in axonal connectivity between the retina and tectum. 5-day-old fish larvae were screened by labeling retinal ganglion cells with DiI and DiO and observing their axonal projections to and on the tectum. 82 mutations, representing 13 complementation groups and 6 single allele loci, were(More)
Membrane carpets consisting of alternating membrane stripes were prepared from plasma membranes of anterior and posterior chick optic tectum. Axons from retinal explants extend neurites on these carpets. Axons of the nasal retina do not distinguish between the stripes. Axons of the temporal retina prefer to extend neurites on anterior tectal membranes.(More)
BACKGROUND Expression of the homeobox-containing gene Engrailed (En) in an increasing rostral-to-caudal gradient in the dorsal mesencephalon is the earliest known marker for polarity of the chick optic tectum. In heterotopic transplantation experiments, En protein expression correlates well with the subsequent gradient of cytoarchitecture as well as the(More)