Tropoelastin production and tropoelastin messenger RNA activity. Relationship to copper and elastin cross-linking in chick aorta.
Tropoelastin production and tropoelastin messenger RNA activity. Relationship to copper and elastin cross-linking in chick aorta.
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原弹性蛋白产生和原弹性蛋白信使 RNA 活性。
DOI：
10.1042/bj2370017
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Rucker,RB
中科院分区：
文献类型：
--
作者：
Tinker,D;Geller,J;Romero,N;Cross,CE;Rucker,RB
鸡胸主动脉的弹性蛋白含量在孵化后的前3周内增加2- 3倍。弹性蛋白的沉积需要通过赖氨酸衍生的交联使原弹性蛋白共价交联。这一过程对膳食铜摄入量敏感，因为铜是赖氨酰氧化酶的辅因子，赖氨酰氧化酶催化交联形成中涉及的赖氨酸残基的氧化脱氨基作用。交联的破坏改变了弹性蛋白和原弹性蛋白的组织浓度，并导致主动脉弹性蛋白含量的净减少。通过改变弹性蛋白或弹性蛋白原的池大小来自动调节弹性蛋白原的合成已被认为是主动脉弹性蛋白含量减少的可能机制。因此，膳食铜缺乏诱导研究弹性蛋白交联形成受损的弹性蛋白原合成的影响。从铜缺乏的小鸡的腹主动脉中的弹性蛋白只有三分之二至一半的量在铜补充小鸡，而铜缺乏的浓度的弹性蛋白原在主动脉中至少5倍高于正常。尽管有这些变化，然而，增加量的弹性蛋白原，铜缺乏和减少量的弹性蛋白没有影响的量的功能性弹性蛋白mRNA在主动脉。同样，无论外植体取自铜充足或缺乏的鸟，主动脉外植体中弹性蛋白原的产生是相同的。铜缺乏小鸡主动脉弹性蛋白的低积累似乎是由于细胞外蛋白水解，而不是合成率下降。主动脉提取物的电泳，然后由原弹性蛋白衍生的产品的免疫检测，表明铜缺乏的鸟类的大肠杆菌中的降解产物。在从铜充足的小鸡，原弹性蛋白的提取物中，没有降解，似乎被纳入弹性蛋白没有进一步的蛋白水解处理。
The elastin content of the chick thoracic aorta increases 2--3-fold during the first 3 weeks post-hatching. The deposition of elastin requires the covalent cross-linking of tropoelastin by means of lysine-derived cross-links. This process is sensitive to dietary copper intake, since copper serves as cofactor for lysyl oxidase, the enzyme that catalyses the oxidative deamination of the lysine residues involved in cross-link formation. Disruption of cross-linking alters tissue concentrations of both elastin and tropoelastin and results in a net decrease in aortic elastin content. Autoregulation of tropoelastin synthesis by changes in the pool sizes of elastin or tropoelastin has been suggested as a possible mechanism for the diminished aortic elastin content. Consequently, dietary copper deficiency was induced to study the effect of impaired elastin cross-link formation on tropoelastin synthesis. Elastin in aortae from copper-deficient chicks was only two-thirds to one-half the amount measured in copper-supplemented chicks, whereas copper-deficient concentrations of tropoelastin in aorta were at least 5-fold higher than normal. In spite of these changes, however, increased amounts of tropoelastin, copper deficiency and decreased amounts of elastin did not influence the amounts of functional elastin mRNA in aorta. Likewise, the production of tropoelastin in aorta explants was the same whether the explants were taken from copper-sufficient or -deficient birds. The lower accumulation of elastin in aorta from copper-deficient chicks appeared to be due to extracellular proteolysis, rather than to a decrease in the rate of synthesis. Electrophoresis of aorta extracts, followed by immunological detection of tropoelastin-derived products, indicated degradation products in aortae from copper-deficient birds. In extracts of aortae from copper-sufficient chicks, tropoelastin was not degraded and appeared to be incorporated into elastin without further proteolytic processing.