Laslop A, Tschernitz C
Department of Pharmacology, University of Innsbruck, Austria.
Neuroscience. 1992 Jul;49(2):443-50. doi: 10.1016/0306-4522(92)90109-f.
We investigated the biosynthesis of various constituents (chromogranins A and B, secretogranin II, carboxypeptidase H and synaptin/synaptophysin) of large dense core and small vesicles in PC12 cells. These cells were treated for up to 18 days with nerve growth factor. Peptide levels were determined by quantitative immunoblotting, their mRNAs by Northern blotting. Nerve growth factor treatment changed the levels of the various peptides investigated and their mRNAs in three patterns. Peptide and mRNA levels for chromogranin A and chromogranin B were increased on day 1 and then declined. Synaptin/synaptophysin levels slightly decreased from day 1 onwards. On the other hand secretogranin II increased steadily up to 217% for peptide levels and 257% for mRNA levels. For carboxypeptidase H for which only the mRNA could be determined an analogous behaviour was seen. Its mRNA after 14 days of nerve growth factor treatment was 459% of controls. These results establish that the biosynthesis of the secretory proteins chromogranin A, chromogranin B and secretogranin II is regulated differentially during nerve growth factor treatment. We suggest that neuronal differentiation is accompanied by an increased biosynthesis of secretogranin II. For carboxypeptidase H, the marked increase in mRNA levels after nerve growth factor treatment is the first example that the biosynthesis of this peptide is significantly up-regulated. Synaptin/synaptophysin biosynthesis is not increased although this peptide is a major constituent of small vesicles which increase in number during nerve growth factor treatment.
我们研究了PC12细胞中大小致密核心囊泡和小囊泡的各种成分（嗜铬粒蛋白A和B、分泌粒蛋白II、羧肽酶H以及突触素/突触囊泡蛋白）的生物合成。这些细胞用神经生长因子处理长达18天。通过定量免疫印迹法测定肽水平，通过Northern印迹法测定其mRNA。神经生长因子处理使所研究的各种肽及其mRNA水平呈现三种变化模式。嗜铬粒蛋白A和嗜铬粒蛋白B的肽和mRNA水平在第1天升高，然后下降。突触素/突触囊泡蛋白水平从第1天起略有下降。另一方面，分泌粒蛋白II稳步增加，肽水平增加至217%，mRNA水平增加至257%。对于只能测定mRNA的羧肽酶H，观察到类似的行为。神经生长因子处理14天后，其mRNA是对照的459%。这些结果表明，在神经生长因子处理期间，分泌蛋白嗜铬粒蛋白A、嗜铬粒蛋白B和分泌粒蛋白II的生物合成受到不同的调节。我们认为神经元分化伴随着分泌粒蛋白II生物合成的增加。对于羧肽酶H，神经生长因子处理后mRNA水平的显著增加是该肽生物合成显著上调的首个例子。尽管突触素/突触囊泡蛋白是小囊泡的主要成分，且在神经生长因子处理期间小囊泡数量增加，但其生物合成并未增加。
