THE SYNAPTOPHYSIN-ENCODING GENE IN RAT AND MAN IS SPECIFICALLY TRANSCRIBED IN NEUROENDOCRINE CELLS
THE SYNAPTOPHYSIN-ENCODING GENE IN RAT AND MAN IS SPECIFICALLY TRANSCRIBED IN NEUROENDOCRINE CELLS
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DOI：
10.1016/0378-1119(91)90127-w
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发表时间：
1991-03-15
期刊：
影响因子：
3.5
通讯作者：
LEUBE, RE
中科院分区：
文献类型：
--
作者：
BARGOU, RCEF;LEUBE, RE
突触素（Synaptophysin，SY）是突触前小泡（30-80 nm）的膜蛋白，也存在于分散的神经内分泌细胞中。由于这种类型的囊泡的发生是特定的两个主要的分化途径，神经元和神经内分泌上皮细胞的SY合成的调节信息，应有助于了解这两种途径共同的监管原则。完整的大鼠和人类单拷贝基因的分离和比较表明，尽管大小的差异（16 kb的大鼠与13 kb的人）内含子/外显子边界是精确保守的。令人惊讶的是，内含子VI在两个物种中均位于3 '非编码区。在大鼠嗜铬细胞瘤衍生的PC 12细胞和大鼠脑中通过引物延伸和S1-核酸酶保护分析确定的主要转录起始点定位于第一个甲硫氨酸密码子的5'端27 nt位点。出乎意料的是，5'上游区没有任何TATA或CAAT盒，而是显示出“管家”基因的典型特征，即，富含G + C的岛和四个Sp1结合基序。使用'核运行'测定，我们已经确定了SY合成在转录水平上受到调控的例子。报告基因构建表明，约。1.2 5 kb的直接上游区域含有启动子/增强子元件，然而，这些元件不足以赋予细胞类型特异性表达，而更上游的序列能够以细胞类型依赖性方式抑制胸苷激酶启动子活性。
Synaptophysin (SY) is an integral membrane protein of presynaptic small (30-80-nm) translucent vesicles also present in dispersed neuroendocrine cells. As the occurrence of this type of vesicle is specific for two major pathways of differentiation, the neuronal and neuroendocrine-epithelial information on the regulation of SY synthesis should contribute to an understanding of regulatory principles common to both pathways. Isolation and comparison of the complete rat and human single-copy genes showed that despite the difference in size (16 kb in rat vs. 13 kb in man) intron/exon boundaries are precisely conserved. Surprisingly, intron VI is located in the 3'-noncoding region in both species. The major transcriptional start point, as determined by primer extension and Sl-nuclease protection analyses in rat pheochromocytoma-derived PC12 cells and rat brain, mapped to a site 27 nt 5' of the first methionine codon. Unexpectedly, the 5' upstream region is devoid of any TATA or CAAT boxes, but shows instead typical features of 'housekeeping' genes, i.e., G + C-rich islands and four Sp 1-binding motifs. Using 'nuclear run-on' assays, we have identified examples in which SY synthesis is regulated at the transcriptional level. Reporter gene constructs showed that approx. 1.2 kb of the immediate upstream region contains promoter/enhancer elements that were, however, insufficient to confer cell-type specific expression, whereas sequences farther upstream were able to suppress thymidine kinase promoter activity in a cell-type-dependent fashion.