Uptake and anterograde axonal transport of wheat germ agglutinin from retina to optic tectum in the chick.

Abstract

The uptake and anterograde axonal transport of ' 25 1-wheat germ agglutinin (WGA) has been investigated in the visual system of the chick . In order to obtain a marker with specific and homogeneous binding properties, the iodinated lectin was affinity purified by passage over an Nacetylglucosamine (NAcGlu)-Sepharose column after iodination . 22 h after vitreal injection of the purified ' 25 1-WGA, radioactive label was found accumulated in the retinoreceptive layers of the contralateral optic tectum. Gel electrophoresis of tectal homogenates revealed that > 80% of the retrieved label ran in a band which comigrated with native WGA . In chicks injected with the fraction of the iodinated preparation that failed to bind to the affinity column, there was no evidence of tectal labeling . These findings support the hypothesis that WGA is selectively taken up by chick retinal ganglion cells and transported intact in an anterograde direction to their axon terminals in the contralateral optic tectum. This raises the possibility that constituents of perikaryal membrane, i .e ., lectin receptors, are transported in an anterograde direction by chick retinal ganglion cells .

Inhibition of Choroidal Neovascularization by Adenovirus-Mediated Delivery of Short Hairpin RNAs Targeting VEGF as a Potential Therapy for AMD

“…39 VEGF has important roles in neuronal function including memory and learning 40 and its receptors are widely expressed in the brain. Indeed, mice deficient in VEGF have a neurodegenerative phenotype analogous to amyotrophic lateral sclerosis.…”

The polymeric immunoglobulin receptor accumulates in specialized endosomes but not synaptic vesicles within the neurites of transfected neuroendocrine PC12 cells.

“…There is some evidence for an indirect neuronal pathway. Lectins such as wheat germ agglutinin bind to the sornatodendritic cell surface, are internalized into the cell body, and are eventually targeted to the nerve terminal by anterograde axonal transport where they can be released and taken up postsynaptically (Steindler and Deniau, 1980;Margolis et al, 1981;Ruda and Coulter, 1982). The targeting of plgR (which reaches the apical surface indirectly via the basolateral surface) to the PC12 neurites suggests that the indirect pathway may also be present in PC12 cells.…”

Localization of axonally transported 125I-wheat germ agglutinin beneath the plasma membrane of chick retinal ganglion cells.

“…For example, the binding of WGA to neuronal membranes has been used to study differences in the carbohydrate composition of neuron cell surfaces during development (14,28,34). We recently found that 12sI-WGA was selectively taken up by chick retinal ganglion cells and transported intact in their axons to the optic tectum (31). The rate at which the iodinated lectin was transported by these cells (30) was within the range of rates of anterograde transport of newly synthesized, endogenous proteins and glycoproteins (l 9, 24,25).…”