(NAS Colloquium) Vision From Photon to Perception (1999) / Chapter Skim
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Cell fate determination in the vertebrate retina
Cell fate determination in the vertebrate retina
Pages 33-39
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From page 33... ...
Two aspects of the descriptive studies of retinal development most salient for the following discussion of cell fate determination are (i) the order of generation of retinal cell types and (ii)
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From page 34... ...
The observations that distinctive retinal cell types can be born at the same time and that retinal progenitor cells are multipotent favor the role of extrinsic cues in directing cell fates. However, as mentioned above, intrinsic properties of progenitor cells must contribute to choice of cell fate as well in that cells must be competent to respond to extrinsic cues to produce the appropriate cell types.
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From page 35... ...
Taurine and vasoactive intestinal peptide were found to be additive in stimulation of the number of cells expressing opsin. Differentiation of other retinal cells, such as ganglion cells (30)
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From page 36... ...
As no chicken homologue of Delta was available, we examined whether Drosophila Delta could inhibit chicken ganglion cell genesis. Coculture of chicken retinal cells with a 50-fold excess of Drosophila cells expressing Delta led to only 9% of the chicken cells expressing ganglion cell antigens.
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From page 37... ...
However, it is possible that the expression of the low molecular weight NF in a subset of retinal progenitors is a marker of the competence of those cells to produce ganglion cells. The marker may be expressed only in a subpopulation of competent cells or may be expressed only in a portion of S phase in a larger group of competent cells, given that 70~o of E4 progenitors are able to respond to the low-density culture environment and differentiate as ganglion cells, but only 5-10% of S phase cells express NF.
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From page 38... ...
A state of competence is transient. It appears that when a cell moves from one state to the next, it cannot go back to a previous state, as discussed above concerning the competence of chicken retinal cells to make ganglion cells (Fig.
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From page 39... ...
Colloquium Paper: Cepko et al.
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