Microtubule-associated protein 1 light chain 3 is a fibronectin mRNA-binding protein linked to mRNA translation in lamb vascular smooth muscle cells.
Microtubule-associated protein 1 light chain 3 is a fibronectin mRNA-binding protein linked to mRNA translation in lamb vascular smooth muscle cells.
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DOI：
10.1172/jci119862
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发表时间：
1997-12
期刊：
影响因子：
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通讯作者：
Bin Zhou;N. Boudreau;C. Coulber;J. Hammarback;M. Rabinovitch
中科院分区：
文献类型：
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作者：
Bin Zhou;N. Boudreau;C. Coulber;J. Hammarback;M. Rabinovitch
在胎儿动脉导管中，纤维连接蛋白依赖的平滑肌细胞迁移形成内膜垫，这与纤维连接蛋白mRNA翻译的更高效率有关。我们通过将含有氯霉素乙酰转移酶编码区的质粒转染平滑肌细胞，并将其3' utr替换为含有完整或突变ARE的纤维连接蛋白3' utr，研究了纤维连接蛋白mRNA 3'-非翻译区（3' utr）中的富au元件（auauuuau）是否参与了这一机制。观察到完整的ARE比突变的ARE更有效地翻译融合mRNA。与非迁移、低纤维连接蛋白产生的主动脉细胞（6.5倍）相比，这种效应在导管中被放大（10.9倍）。用野生型但未突变的质粒转染的导管细胞恢复为与纤维连接蛋白产生减少相关的主动脉细胞的星状表型。这表明质粒ARE隔离rna结合因子，从而减少内源性纤维连接蛋白mRNA的翻译。接下来，我们纯化了一个15-kD的纤维连接蛋白依赖rna结合蛋白，并将其鉴定为微管相关蛋白1轻链3 （LC3）。与主动脉细胞相比，主动脉细胞中LC3的含量更高，转染主动脉细胞中LC3的过表达可使纤连蛋白mRNA翻译到导管细胞中观察到的水平。
Intimal cushions form in the fetal ductus arteriosus by fibronectin-dependent smooth muscle cell migration which is associated with greater efficiency of fibronectin mRNA translation. We investigated whether the AU-rich element (ARE), UUAUUUAU, in the 3'-untranslated region (3'UTR) of fibronectin mRNA is involved in this mechanism by transfecting smooth muscle cells with plasmids containing the chloramphenicol acetyltransferase coding region with its 3'UTR replaced by fibronectin 3'UTR bearing intact or mutated ARE. More efficient translation of fusion mRNA with intact versus mutated ARE was observed. This effect was amplified in ductus (10.9-fold) compared with nonmigratory, lower fibronectin-producing aorta cells (6.5-fold). Ductus cells transfected with wild-type but not ARE-mutated plasmid reverted to the stellate phenotype of aorta cells associated with reduced fibronectin production. This suggested that plasmid ARE sequesters RNA-binding factors, thereby reducing endogenous fibronectin mRNA translation. We next purified a 15-kD fibronectin ARE-dependent RNA-binding protein and identified it as microtubule-associated protein 1 light chain 3 (LC3). LC3 is present in greater amounts in ductus compared with aorta cells, and overexpression of LC3 in aortic cells by transfection enhances fibronectin mRNA translation to levels observed in ductus cells.