Kumar S, Holmes E, Scully S, Birren B W, Wilson R H, de Vellis J
J Neurosci Res. 1986;16(1):251-64. doi: 10.1002/jnr.490160122.
Increases in the mRNA levels of two neuroglial markers, glutamine synthetase (EC 6.3.1.2; GS) and glycerolphosphate dehydrogenase (EC 1.1.1.8; GPDH), were observed in hydrocortisone-treated cultures of astrocytes and oligodendrocytes, respectively, and in C6 cells by Northern blot analysis and in situ hybridization. In vitro transcription assays demonstrated increased GS transcription in isolated nuclei from hydrocortisone (HC)-treated primary cultures of astrocytes and C6 cells, relative to untreated cells. This increased transcription is reflected in increased GS mRNA levels in the cytoplasm and increased levels of GS protein synthesis. Sodium butyrate (NaB) blocked the glucocorticoid-mediated increase in GS transcription in the primary cultures of astrocytes but not in C6 cells. From our earlier observations (Kumar et al: J Neurochem 43:1455-1463, 1984) we found NaB in combination with HC to increase the levels of GS mRNA and GS protein synthesis (Weingarten et al: FEBS Lett 126:289-291, 1981). We now report that NaB, alone or in combination with HC, does not increase the rate of transcription, suggesting that NaB plays a role in post-transcriptional regulation of GS in C6. In addition, we report the presence of two distinct sizes of GS mRNA, 2.9 and 1.8 kb, in the primary cultures of astrocytes and C6 cells.
通过Northern印迹分析和原位杂交发现，在氢化可的松处理的星形胶质细胞和少突胶质细胞培养物中，以及在C6细胞中，分别观察到两种神经胶质标记物谷氨酰胺合成酶（EC 6.3.1.2；GS）和甘油磷酸脱氢酶（EC 1.1.1.8；GPDH）的mRNA水平升高。体外转录试验表明，相对于未处理的细胞，氢化可的松（HC）处理的星形胶质细胞和C6细胞原代培养物的分离核中GS转录增加。这种转录增加反映在细胞质中GS mRNA水平的增加以及GS蛋白质合成水平的增加。丁酸钠（NaB）阻断了糖皮质激素介导的星形胶质细胞原代培养物中GS转录的增加，但对C6细胞没有作用。根据我们早期的观察结果（Kumar等人：《神经化学杂志》43:1455 - 1463，1984年），我们发现NaB与HC联合使用可增加GS mRNA水平和GS蛋白质合成（Weingarten等人：《欧洲生物化学学会联合会快报》126:289 - 291，1981年）。我们现在报告，单独使用NaB或与HC联合使用均不会增加转录速率，这表明NaB在C6细胞中GS的转录后调控中起作用。此外，我们报告在星形胶质细胞和C6细胞的原代培养物中存在两种不同大小的GS mRNA，分别为2.9 kb和1.8 kb。
