Rapid insulin-stimulated accumulation of an mRNA encoding a proline-rich protein.
Rapid insulin-stimulated accumulation of an mRNA encoding a proline-rich protein.
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DOI：
10.1016/s0021-9258(17)46259-4
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发表时间：
1990-09
期刊：
影响因子：
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通讯作者：
W. Lai;D. Stumpo;P. J. Blackshear
中科院分区：
文献类型：
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作者：
W. Lai;D. Stumpo;P. J. Blackshear
通过对源自胰岛素刺激细胞的 cDNA 文库进行差异杂交筛选，我们选择了与响应胰岛素而快速积累的 mRNA 杂交的克隆。来自该克隆的插入片段编码推定的Mr 33,600 多肽，pI 11.2；由于该蛋白质富含脯氨酸残基（14.4 mol%）并且包含三个 Pro-Pro-Pro-Pro 重复序列，因此我们暂时将其标记为三四脯氨酸（TTP）。该蛋白质的功能尚不清楚，但它包含两个富含脯氨酸（30-40 mol%）的区域；类似的富含脯氨酸的区域已被证明参与其他蛋白质的转录激活。在去血清的 HIR 3.5 细胞中，编码 TTP 蛋白的 mRNA（2.0 KB）基本上检测不到，但在胰岛素刺激后 10 分钟内急剧积累。这种效应似乎是由于胰岛素通过其自身受体的内在蛋白酪氨酸激酶活性发挥作用。放线菌酮可过度诱导胰岛素诱导的 TTP mRNA 积累。多种生长因子和活性佛波酯也会刺激 TTP mRNA 的积累；然而，在蛋白激酶 C 耗尽的细胞中，胰岛素作用实际上是正常的。小鼠基因组中似乎存在单个 TTP 基因。该基因加入了一组基因，其成员响应胰岛素和其他有丝分裂原而快速转录。
By differential hybridization screening of a cDNA library derived from insulin-stimulated cells, we selected a clone which hybridized to an mRNA species that rapidly accumulated in response to insulin. The insert from this clone encoded a putative polypeptide of Mr 33,600, pI 11.2; because the protein was enriched in proline residues (14.4 mol %) and contained three Pro-Pro-Pro-Pro repeats, we have tentatively labeled it tris-tetraprolin (TTP). The function of this protein is not known, but it contains two regions very rich in proline (30-40 mol %); similar proline-rich regions have been shown to be involved in transcriptional activation by other proteins. The mRNA (2.0 kilobases) encoding the TTP protein was essentially undetectable in serum-deprived HIR 3.5 cells, but accumulated dramatically within 10 min of stimulation by insulin. This effect appeared to be due to insulin acting through the intrinsic protein-tyrosine kinase activity of its own receptor. Insulin induction of TTP mRNA accumulation was prevented by actinomycin D and superinduced by cycloheximide. Accumulation of TTP mRNA was also stimulated by a variety of growth factors and active phorbol esters; however, the insulin effect was virtually normal in cells depleted of protein kinase C. A single TTP gene appeared to be present in the mouse genome. This gene joins the group of genes whose members are rapidly transcribed in response to insulin and other mitogens.