A glial protein specific for the nervous system.

Abstract

In many organs, part of the over-all protein synthesis serves the growth of cells by completing the new members of the cell population which arise after mitosis. In the adult brain, the neurons appear to undergo mitosis only to a very limited extent, while glial cells do divide under special circumstances.' Thus, cell renewal and growth cannot account for the main part of the extensive protein synthesis occurring in the brain.In an effort to explain the role of protein turnover in brain function, extensive efforts are under way in a number of laboratories to isolate proteins specific to the brain and to determine their cellular localization, metabolic half life, and function. Moore and co-workers2 3 have recently isolated and characterized an acidic protein (named S100 protein) specific to nervous tissue which makes up 0.5 per cent of the brain's soluble proteins. Antiserum to this protein, isolated from beef brain, showed cross reaction to protein from all vertebrate species examined. 4 The suggestion has been made that the S100 protein is located in glial cells,5 while another proposal has been made that it is a neuronal protein.3 In this paper, evidence will be presented that the S100 protein is mainly localized in the glial system of the Deiters' nucleus of the rabbit brain stem. The S100 protein is also found in the cell nuclei of the large neurons, while it is distinctly absent from the nuclei of the glial cells.Material and Methods.-Microanalysis: The large neurons and surrounding glia from the lateral vestibular (Deiters') nucleus of the rabbit brain stem were used. After rapid removal of the brain stem, a section was placed at the rostral boundary of the tubercula acustica. The sections of both sides, 3-4 mm thick, were placed in cold 0.25 M sucrose solution. The neurons or the glia were separated and cleaned by freehand dissection as previously described.6 The reason for using these types of neurons is that many data on their biochemical characteristics have been collected during the last 10 years. Also, the relationship between the Deiters' neuron and its surrounding glia has been elucidated in measurements of enzymatic activity and RNA studies.7 -10 Each Deiters' nerve cell has a dry weight of 2 X 10-8 gm. The dry weight per .s3 for both the nerve cell body and the surrounding glia is 0.20 juug. Therefore, biochemical data obtained on the same volume of neurons or glia can be compared.Twenty to thirty nerve cells or glial samples are transferred by freehand manipulation to a drop of homogenizing solution on top of a Teflon homogenizer pestle, 2 mm in diameter. The cells are homogenized in 20 Al of distilled water containing 0.5% w/v Triton X-100. After homogenization, centrifugation took place in 0.5-mm capillary tubes at 12,000 rpm.Single diffusion agar precipitation using antiserum against the S100 protein was performed in glass capillaries, 300 IA or 500 A in diameter (Microcaps: Drummond Scientific Co., Broomall, Pennsylvania), according to a micromodification of Oudin's technique."1 Agar in a ...

In vitro segregation of different cell lines with neuronal and glial properties from a stem cell line of rat neurotumor RT4.

“…RT4-AC possesses properties of a stem cell by generating morphologically distinct cell types RT4-B, RT4-D, and RT4-E in culture (cell type conversion). The stem cell type (RT4-AC) and one of the morphologically distinct cell types (RT4-D) produce the nervous system-specific protein S100, which is a characteristic glial protein (2,3). Its production, however, is completely arrested when the stem cell differentiates into the other two types, RT4-B and RT4-E. Tumorigenicity is also correlated with cell types: cell types RT4-AC and RT4-D are tumorigenic, whereas RT4-B and RT4-E are not (4).…”

Synthesis of a Brain-Specific Protein (S100 Protein) in a Homologous Cell-Free System Programmed with Cerebral Polysomal Messenger RNA

“…2, Table 1). Furthermore, since S100 protein has been shown to be primarily of glial origin (24)(25)(26), gross brain fractions were assayed that contained different proportions of glial cells. The polysomal system obtained from hindbrain-medullary white matter, with the highest proportion of glial cells (56), showed the greatest in vitro synthesis of the S100 protein.…”

“…The isolation, purification, and characterization of two brain-specific low molecular weight proteins by Moore et al, as well as preparation of antisera to these proteins, has made possible a study of the in vitro synthesis of specific brain proteins by cerebral polyribosomes. The S100 protein (23) is primarily of glial origin (24)(25)(26), and represents 0.2% of the total soluble protein of brain. The other purified protein (14-3-2) is localized primarily in neurons (27).…”

<b>A MOUSE HYBRIDOMA CELL LINE PRODUCING A MONOCLONAL ANTIBODY SPECIFIC FOR THE S-100α SUBUNIT: REACTIVITY OF THE ANTIBODY VVITH BRAINS OF VARIOUS ANIMAL SPECIES</b>

“…Additional bands with lower mobilities were also found. On the other hand, S-100b (5,8) sample gave rise to the fast moving band and a trace of the slow moving band (lane 3 in Fig. 3a).…”

“…Immunohistochemical studies have shown that S-100 protein is mainly present in glial cells (5,16,19,20,23,25) and Schwann cells (16,25,26,31,41), and occasionally in some neurons (2,5,25,37) in the nervous system of various animals. S-100 has also been localized in some cells of non-nervous tissue such as Langerhans cells of drocytes (33) and melanocytes (27).…”