Srivastava M, Gibson K R, Pollard H B, Fleming P J
Laboratory of Cell Biology and Genetics, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
Biochem J. 1994 Nov 1;303 ( Pt 3)(Pt 3):915-21. doi: 10.1042/bj3030915.
Cytochrome b561 is a major transmembrane protein of catecholamine and neuropeptide secretory vesicles. In this report, we describe the cloning and properties of a full-length cDNA encoding human neuroendocrine cytochrome b561 from a human caudate cDNA library and a human peripheral blood genomic library. The human cDNA contains two major transcription start sites and only one translation start site that codes for an apocytochrome b561, which is 22 amino acid residues smaller than the previously deduced amino acid sequence from bovine cDNA. This smaller version of cytochrome b561 may contain only five transmembrane segments rather than the previously proposed six segments. The new model is in agreement with our previous results on transmembrane topology of the gene product. Northern-blot analysis shows an expanded tissue distribution of cytochrome mRNA expression where previous immunological assays were negative. These results support the hypothesis that cytochrome b561 is a marker for peptidergic and adrenergic tissues.
细胞色素b561是儿茶酚胺和神经肽分泌囊泡的一种主要跨膜蛋白。在本报告中，我们描述了从人尾状核cDNA文库和人外周血基因组文库中克隆编码人神经内分泌细胞色素b561的全长cDNA及其特性。该人cDNA包含两个主要转录起始位点和一个编码脱辅基细胞色素b561的翻译起始位点，其比先前从牛cDNA推导的氨基酸序列少22个氨基酸残基。细胞色素b561的这个较小版本可能仅包含五个跨膜区段，而非先前提出的六个区段。新模型与我们先前关于该基因产物跨膜拓扑结构的结果一致。Northern印迹分析显示细胞色素mRNA表达的组织分布扩大，而先前的免疫测定为阴性。这些结果支持细胞色素b561是肽能和肾上腺素能组织标志物的假说。
