In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 92, No. 21 ( 1995-10-10), p. 9834-9838
Abstract:
Early neurogenesis progresses by an initial massive proliferation of neuroepithelial cells followed by a sequential differentiation of the various mature neural cell types. The regulation of these processes by growth factors is poorly understood. We intend to understand, in a well-defined biological system, the embryonic chicken retina, the role of the insulin-related growth factors in neurogenesis. We demonstrate the local presence of signaling elements together with a biological response to the factors. Neuroretina at days 6-8 of embryonic development (E6-E8) expressed proinsulin/insulin and insulin-like growth factor I (IGF-I) mRNAs as well as insulin receptor and IGF type I receptor mRNAs. In parallel with this in vivo gene expression, E5 cultured neuroretinas synthesized and released to the medium a metabolically radiolabeled immunoprecipitable insulin-related peptide. Furthermore, insulin-related immunoreactive material with a HPLC mobility close to that of proinsulin was found in the E6-E8 vitreous humor. Exogenous chicken IGF-I, human insulin, and human proinsulin added to E6 cultured neuroretinas showed relatively close potencies stimulating proliferation, as determined by [methyl-3H]thymidine incorporation, with a plateau reached at 10(-8) M. These factors also stimulated neuronal differentiation, indicated by the expression of the neuron-specific antigen G4. Thus, insulin-related growth factors, interestingly including proinsulin, are present in the developing chicken retina and appear to play an autocrine/paracrine stimulatory role in the progression of neurogenesis.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.92.21.9834
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
1995
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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