Samuel J L, Farhadian F, Sabri A, Marotte F, Robert V, Rappaport L
U 127 INSERM, IFR circulation, Université D Diderot, Paris, France.
Cardiovasc Res. 1994 Nov;28(11):1653-61. doi: 10.1093/cvr/28.11.1653.
Fibronectin is a protein of the extracellular matrix with numerous binding sites to the other elements of the matrix and to the cells. The aim of this study was to determine the relative importance of fibronectin isoform expression (FN-EIIIA, FN-EIIIB) during fetal and postnatal development of the rat heart.
In situ hybridisation and immunolabelling approaches were used to describe the cellular synthesis of fibronectin and its distribution throughout the rat heart from 11 d postconception until adulthood. The distribution of fibronectin was compared to that of laminin and of alpha type III procollagen.
The accumulation and pattern of distribution of the major fibronectin mRNA isoforms were identical, that is, there was a progressive decrease in their accumulation as a function of time after 11 d postconception, resulting in a complete absence in the adult. The distribution of fibronectin and procollagen type III mRNAs were, however, quite distinct. At the protein level the time course of synthesis and secretion of the locally synthesised fibronectin (c-FN) did not follow fibronectin mRNA expression, the accumulation of the protein being rather poor, except just before birth, where it was found mainly in the coronary vessels.
During the development of the fetal rat heart fibronectin gene transcription is active and progressively decreases with age, whereas the translation of the mRNAs into their corresponding proteins is always relatively poor. If fibronectin is involved in fetal and postnatal morphogenesis of the rat myocardium, it is the plasma form (p-FN) that is most probably involved in the process of growth and differentiation of the rat heart.
纤连蛋白是细胞外基质中的一种蛋白质，它具有众多与基质其他成分及细胞结合的位点。本研究的目的是确定纤连蛋白异构体表达（FN-EIIIA、FN-EIIIB）在大鼠心脏胎儿期和出生后发育过程中的相对重要性。
采用原位杂交和免疫标记方法来描述从受孕后11天直至成年大鼠心脏中纤连蛋白的细胞合成及其分布。将纤连蛋白的分布与层粘连蛋白和α-III型前胶原的分布进行比较。
主要纤连蛋白mRNA异构体的积累和分布模式相同，也就是说，受孕后11天之后，它们的积累随时间逐渐减少，在成年时完全消失。然而，纤连蛋白和III型前胶原mRNA的分布却截然不同。在蛋白质水平上，局部合成的纤连蛋白（c-FN）的合成和分泌时间进程并不遵循纤连蛋白mRNA的表达，该蛋白的积累相当少，除了在出生前，此时它主要存在于冠状血管中。
在胎儿大鼠心脏发育过程中，纤连蛋白基因转录活跃且随年龄逐渐减少，而mRNA翻译成相应蛋白质的过程始终相对较差。如果纤连蛋白参与大鼠心肌的胎儿期和出生后形态发生，那么最有可能参与大鼠心脏生长和分化过程的是血浆形式（p-FN）。
