DIETARY TRYPTOPHAN IN CONTROLLING PROTEIN SYNTHESIS

这项调查感兴趣的是探索单一的 必需氨基酸，特别是L-色氨酸，影响蛋白质 肝脏的新陈代谢。在我们实验室早先的报告中 我们已经描述了L色氨酸对肝脏的快速刺激 多聚核糖体聚集和蛋白质合成。这一效果 似乎与转录和转录水平的改变有关 转录后控制。我们目前的提案计划 在细胞和亚细胞水平上探索L-色氨酸如何 可能直接作用于细胞核(核膜)，以 刺激核浆内增强的信使核转位。我们 计划详细研究细胞质和细胞核中的蛋白质是如何 色氨酸处理的大鼠肝脏膜参与了 核质转位增加。鉴于…… 我们最近的发现是有特定的色氨酸结合 在大鼠肝脏核膜上的位置，我们现在正在探索 该绑定相对于 色氨酸促进肝脏核糖核酸的释放。我们 计划表征原子核的结构和性质 包膜色氨酸结合蛋白(S)。我们还计划确定 色氨酸特异性结合是否会受到变化的影响 在肝脏中，如由动物用一种 多种肝毒剂。这样的信息可以提供基本的 洞察到一个重要的饮食成分是如何 由L-色氨酸组成，可能在哺乳动物肝脏中起到调节作用 蛋白质代谢。

This investigation is interested in exploring how a single essential amino acid, specifically L-tryptophan, affects protein metabolism in the liver. In earlier reports from our laboratory we have described that L-tryptophan rapidly stimulates hepatic polyribosomal aggregation and protein synthesis. This effect appears to be related to alterations in both transcriptional and posttranscriptional controls. Our present proposal plans to explore at the cellular and subcellular levels how L-tryptophan may act, possibly directly on the nucleus (nuclear membrane), to stimulate enhanced nucleocytoplasmic translocation of mRNA. We plan to study in detail how proteins of the cytosol and nuclear membranes of the livers of tryptophan-treated rats are involved in the increased nucleocytoplasmic translocation of mRNA. In view of our recent findings that there are specific tryptophan binding sites on the nuclear envelopes of rat liver, we are now exploring the possible significance of the binding in relation to the enhanced nuclear RNA release in the liver due to tryptophan. We plan to characterize the structure and properties of the nuclear envelope tryptophan binding protein(s). Also we plan to determine whether the tryptophan specific binding may be affected by changes in the liver, such as induced by pretreatment of animals with a variety of hepatotoxic agents. Such information may offer basic insight as to how an important dietary component, as exemplified by L-tryptophan, may play a regulatory role in mammalian liver protein metabolism.