Differential processing of colony-stimulating factor 1 precursors encoded by two human cDNAs.
Differential processing of colony-stimulating factor 1 precursors encoded by two human cDNAs.
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由两种人类 cDNA 编码的集落刺激因子 1 前体的差异处理。
DOI：
10.1128/mcb.8.11.5026-5034.1988
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发表时间：
1988
影响因子：
5.3
通讯作者：
Roussel,MF
中科院分区：
文献类型：
--
作者：
Rettenmier,CW;Roussel,MF
用逆转录病毒载体表达人4千碱基(Kb)554个氨基酸产物，在NIH-3T3成纤维细胞中检测巨噬细胞集落刺激因子-1(CSF-1)的生物合成。与以前用1.6kb的人编码256个氨基酸的csf-1前体的结果相似，本研究的结果表明，表达4kb克隆产物的NIH-3T3细胞产生具有生物活性的人csf-1，当与含有人c-fms(csf-1受体)cDNAs的载体共转染时，NIH-3T3细胞以自分泌机制转化。4kb的CSF-1cDNA产物被合成为一个完整的跨膜糖蛋白，它被组装成二硫键连接的二聚体，并迅速经过蛋白水解酶切割产生可溶性生长因子。尽管1.6kb的人cDNA所指定的较小的CSF-1前体在细胞表面以膜结合糖蛋白的形式稳定表达，并被缓慢切割以释放细胞外生长因子，但4-kb克隆的细胞相关产物被有效地加工成分泌型，在质膜上检测不到。糖苷酶消化表明，4kb克隆编码的可溶性CSF-1既含有天冬酰胺(N)连接的碳水化合物链，也含有O连接的碳水化合物链，而1.6kb克隆的产物仅含有N连接的寡糖。去除碳水化合物表明，分泌的4-kb cDNA产物的多肽链比由较小克隆编码的相应形式的多肽链更长。翻译后加工的这些差异可能反映了两种CSF-1前体产物在体内的不同生理作用。
The biosynthesis of macrophage colony-stimulating factor 1 (CSF-1) was examined in mouse NIH-3T3 fibroblasts transfected with a retroviral vector expressing the 554-amino-acid product of a human 4-kilobase (kb) CSF-1 cDNA. Similar to results previously obtained with a 1.6-kb human cDNA that codes for a 256-amino-acid CSF-1 precursor, the results of the present study showed that NIH-3T3 cells expressing the product of the 4-kb clone produced biologically active human CSF-1 and were transformed by an autocrine mechanism when cotransfected with a vector containing a human c-fms(CSF-1 receptor) cDNA. The 4-kb CSF-1 cDNA product was synthesized as an integral transmembrane glycoprotein that was assembled into disulfide-linked dimers and rapidly underwent proteolytic cleavage to generate a soluble growth factor. Although the smaller CSF-1 precursor specified by the 1.6-kb human cDNA was stably expressed as a membrane-bound glycoprotein at the cell surface and was slowly cleaved to release the extracellular growth factor, the cell-associated product of the 4-kb clone was efficiently processed to the secreted form and was not detected on the plasma membrane. Digestion with glycosidic enzymes indicated that soluble CSF-1 encoded by the 4-kb cDNA contained both asparagine(N)-linked and O-linked carbohydrate chains, whereas the product of the 1.6-kb clone had only N-linked oligosaccharides. Removal of the carbohydrate indicated that the polypeptide chain of the secreted 4-kb cDNA product was longer than that of the corresponding form encoded by the smaller clone. These differences in posttranslational processing may reflect diverse physiological roles for the products of the two CSF-1 precursors in vivo.