Cell-specific post-translational processing of preproglucagon expressed from a metallothionein-glucagon fusion gene.
Cell-specific post-translational processing of preproglucagon expressed from a metallothionein-glucagon fusion gene.
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DOI：
10.1016/s0021-9258(18)67561-1
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发表时间：
1986-07
期刊：
影响因子：
--
通讯作者：
D. Drucker;S. Mojsov;J. Habener
中科院分区：
文献类型：
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作者：
D. Drucker;S. Mojsov;J. Habener
胰高血糖素是由前激素原编码的29个氨基酸的肽激素，前激素原串联含有胰高血糖素和两个另外的胰高血糖素样肽（GLP）的序列，所述另外的胰高血糖素样肽（GLP）在结构上与胰高血糖素相关并且被插入肽分开。胰高血糖素通过从胰岛A细胞内的激素原裂解而产生，但在肠中仍作为部分加工的前体（胰高血糖素）的一部分。为了确定是否有额外的胰高血糖素样肽从preproglucagon加工和分析潜在的细胞特异性在preproglucagon的加工，我们介绍和表达的金属硫蛋白-胰高血糖素融合基因在成纤维细胞和两个内分泌（垂体和胰岛）细胞系。利用对化学合成肽的特异性放射免疫测定对细胞提取物进行色谱分析，证明释放了完整的胰高血糖素、胰高血糖素、GLP-1（1-37）、GLP-1（7-37）、GLP-II和在其羧基末端酰胺化的插入肽。这些肽在两种内分泌细胞系而不是成纤维细胞系中以不同的模式存在。胰高血糖素样肽和间插肽的细胞特异性释放表明它们作为新的生物活性肽的潜力。前胰高血糖素原加工的细胞特异性表明，加工活性的遗传决定因素是复杂的，并以细胞特异性方式表达。
Glucagon is a peptide hormone of 29 amino acids encoded by a preprohormone which contains in tandem the sequences of glucagon and two additional glucagon-like peptides (GLPs) structurally related to glucagon and separated by intervening peptides. Glucagon arises by cleavage from the prohormone within the A cells of the pancreatic islets but in the intestine remains as part of a partially processed precursor (glicentin). To determine whether additional glucagon-like peptides are processed from preproglucagon and to analyze for potential cellular specificity in the processing of preproglucagon, we introduced and expressed a metallothionein-glucagon fusion gene in a fibroblast and two endocrine (pituitary and pancreatic islet) cell lines. Chromatographic analyses of cell extracts utilizing specific radioimmunoassays to chemically synthesized peptides demonstrate the liberation of intact glucagon, glicentin, GLP-I(1-37), GLP-I(7-37), GLP-II, and an intervening peptide amidated at its carboxyl terminus. The peptides were present in distinct yet different patterns in the two endocrine but not the fibroblast cell lines. The cell-specific liberation of the glucagon-like and intervening peptides suggests their potential as new bioactive peptides. The cellular specificity in the processing of preproglucagon indicates that the genetic determinants of the processing activity are complex and are expressed in a cell-specific manner.