Condorelli D F, Nicoletti V G, Dell'Albani P, Barresi V, Caruso A, Conticello S G, Belluardo N, Giuffrida Stella A M
Institute of Biochemistry, Faculty of Medicine, University of Catania, Italy.
Neurochem Res. 1999 May;24(5):709-14. doi: 10.1023/a:1021016828704.
GFAPbeta mRNA is an alternative transcript of the glial fibrillary acidic protein (GFAP) gene, whose transcriptional start site is located 169 nucleotides upstream to the classical GFAPalpha mRNA. By an RT-PCR method with primers on separate exons, we were able to confirm the presence of GFAP transcripts with a longer 5' untranslated region in all the examined areas of rat brain and in primary cultures of astroglial cells. Northern blot analysis, using an oligoprobe specific for the 5' region of GFAPbeta, revealed a single hybridization band of 2.9 kb in all the brain regions examined and in primary cultures of astroglial cells. The availability of the quantitative Northern blot assay allowed further studies on the regulation of GFAPbeta expression in vivo. Since it is well-known that neuronal brain injury is one of the most powerful inducers of GFAP, we examined the expression of GFAPalpha and beta after a neurotoxic lesion in the rat hippocampus. Results obtained show a parallel increase in both GFAP transcripts with an identical time-course, suggesting that regulatory regions of the gene influence in similar way the rate of transcription at the two different start sites (alpha and beta) or that a similar post-transcriptional mechanism is involved in regulating both mRNA isoforms.
胶质纤维酸性蛋白β（GFAPβ）信使核糖核酸（mRNA）是胶质纤维酸性蛋白（GFAP）基因的一种可变转录本，其转录起始位点位于经典的胶质纤维酸性蛋白α（GFAPα）mRNA上游169个核苷酸处。通过使用位于不同外显子上的引物进行逆转录聚合酶链反应（RT-PCR）方法，我们能够证实在大鼠脑的所有检测区域以及星形胶质细胞原代培养物中均存在具有更长5'非翻译区的GFAP转录本。使用针对GFAPβ 5'区域的寡核苷酸探针进行的Northern印迹分析显示，在所有检测的脑区域以及星形胶质细胞原代培养物中均有一条2.9 kb的单一杂交带。定量Northern印迹分析方法的可用性使得能够进一步研究GFAPβ在体内表达的调控。由于众所周知神经元性脑损伤是GFAP最有力的诱导因素之一，我们检测了大鼠海马体神经毒性损伤后GFAPα和β的表达。所获得的结果显示两种GFAP转录本均以相同的时间进程平行增加，这表明该基因的调控区域以相似的方式影响两个不同起始位点（α和β）的转录速率，或者一种相似的转录后机制参与调控这两种mRNA异构体。
