Magin Angela, Lietz Michael, Cibelli Giuseppe, Thiel Gerald
Department of Medical Biochemistry and Molecular Biology, University of Saarland Medical Center, D-66421, Homburg, Germany.
Neurochem Int. 2002 Mar;40(3):195-202. doi: 10.1016/s0197-0186(01)00091-2.
The zinc finger protein RE-1 silencing transcription factor (REST) is a transcriptional repressor that represses neuronal genes in non-neuronal tissues. A neuronal splice form of REST, termed REST4, has been described in the rat. It encompasses the N-terminus of REST, including the N-terminal repressor domain and five of the eight zinc fingers of the DNA-binding domain. The biological function of REST4 is controversial. Transcriptional repression as well as transcriptional de-repression activity has been attributed to the REST4 protein of rat. Here, we have expressed a 'humanized' version of REST4 (hREST4) to facilitate a comparison of the biological functions of hREST4 and REST. The biological activity the human REST protein has been extensively studied in the past. Additionally, hREST4 has a high degree of homology with the REST4 protein of rat. An immunofluorescence analysis showed that hREST4 is expressed in the nucleus, indicating that the protein may have a potential impact on gene regulation. We analyzed the biological function of hREST4 in NS20Y neuroblastoma cells using human synapsin I promoter/reporter gene constructs. The human synapsin I gene is negatively regulated by REST. The results show that hREST4, in contrast to the full-length human REST protein, does not impair human synapsin I promoter activity. Moreover, co-transfection experiments with expression vectors encoding REST and hREST4 did not reveal any evidence that REST4 blocks the transcriptional repression activity of REST.
锌指蛋白RE-1沉默转录因子（REST）是一种转录抑制因子，可在非神经组织中抑制神经元基因。在大鼠中已描述了一种REST的神经元剪接形式，称为REST4。它包含REST的N端，包括N端抑制域和DNA结合域八个锌指中的五个。REST4的生物学功能存在争议。大鼠的REST4蛋白具有转录抑制以及转录去抑制活性。在此，我们表达了一种“人源化”的REST4（hREST4），以便比较hREST4和REST的生物学功能。过去已对人REST蛋白的生物学活性进行了广泛研究。此外，hREST4与大鼠的REST4蛋白具有高度同源性。免疫荧光分析表明hREST4在细胞核中表达，这表明该蛋白可能对基因调控有潜在影响。我们使用人突触素I启动子/报告基因构建体分析了hREST4在NS20Y神经母细胞瘤细胞中的生物学功能。人突触素I基因受REST负调控。结果表明，与全长人REST蛋白相比，hREST4不会损害人突触素I启动子活性。此外，用编码REST和hREST4的表达载体进行的共转染实验未发现任何证据表明REST4会阻断REST的转录抑制活性。
