Borsi L, Balza E, Castellani P, Carnemolla B, Ponassi M, Querzé G, Zardi L
Laboratory of Cell Biology, Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy.
Cell Adhes Commun. 1994 Jan;1(4):307-17. doi: 10.3109/15419069409097262.
Functionally different tenascin (TN) isoforms may be generated by alternative splicing of the TN primary transcript. In fact, it has been demonstrated that only the larger TN isoform containing the alternatively spliced region induces loss of focal adhesion in cultured cells and seems able to facilitate cell migration. Recent studies have shown that the higher molecular mass TN isoform is a marker of stromal cell proliferation in hyperplastic and neoplastic breast tissues. This finding prompted us to study the pattern of TN alternative splicing in proliferating and non-proliferating cultured fibroblasts. Here, we show that the mitogenic stimulation of fibroblasts with serum or cytokines leads to an early and striking modification in the steady-state levels of the two major TN mRNAs. We also show that de novo protein synthesis is not necessary for this modification, indicating that it is a "primary response" event. Similarly, mitogenic stimulation induces changes both in synthesis and accumulation of the different TN isoforms.
功能不同的腱生蛋白（TN）同工型可能由TN初级转录本的可变剪接产生。事实上，已经证明只有包含可变剪接区域的较大TN同工型会导致培养细胞中粘着斑的丧失，并且似乎能够促进细胞迁移。最近的研究表明，较高分子量的TN同工型是增生性和肿瘤性乳腺组织中基质细胞增殖的标志物。这一发现促使我们研究增殖和非增殖培养成纤维细胞中TN可变剪接的模式。在这里，我们表明，用血清或细胞因子对成纤维细胞进行促有丝分裂刺激会导致两种主要TN mRNA的稳态水平发生早期且显著的改变。我们还表明，这种修饰不需要从头合成蛋白质，这表明它是一个“初级反应”事件。同样，促有丝分裂刺激会诱导不同TN同工型的合成和积累发生变化。
