CONTROL OF HISTONE MRNA SYNTHESIS

组蛋白信使核糖核酸的浓度与DNA的合成是平行的。 组蛋白信使核糖核酸有两类：主要的一类是受调控的 和复制组蛋白变体的代码，以及一个次要类，它是 由替换组蛋白变异体的代码组成地表达。这个 组蛋白mRNA水平在细胞周期和信号转导过程中受到调节 这可能与调节DNA和组蛋白的合成有关。三大 问题将被解决：1.核酸序列是什么 参与了组蛋白mRNA水平的调节。其中包括DNA序列 参与转录调控和参与转录的mRNA序列 信使核糖核酸半衰期调控。具体地说，在 复制和替换组蛋白变异体之间的基因结构 这两家公司的监管不同。我们将通过以下方式回答这个问题 构建变异基因，将其导入细胞并进行监测 他们的监管行为。特别是，我们将构建杂交基因 包含复制和替换变体的不同部分 组蛋白，看看哪些部分在调节中是重要的。2.什么是 调节组蛋白mRNA水平的信号？组蛋白mRNA的水平是 由改变脱氧核苷酸新陈代谢的试剂调节。假说 将对一种不寻常的核苷酸调节组蛋白mRNA水平进行测试。 伴随而来的细胞内核苷酸变化 将分析组蛋白mRNA水平的变化。一种无细胞系统 可以用来分析这种信号的方法将被开发出来。3.为什么 3号染色体上的一簇组蛋白基因在5到10倍于 13号染色体上组蛋白基因的数量？基因将被构建成 组蛋白基因上增强子序列的可能性测试 3号染色体。

Histone mRNA concentrations are regulated in parallel with DNA synthesis. There are two classes of histone mRNA; the major class which is regulated and codes for the replication histone variants, and a minor class, which is constitutively expressed by codes for replacement histone variants. The histone mRNA levels are regulated during the cell cycle and the signals which regulate DNA and histone synthesis may be related. Three major questions will be addressed: 1. What are the nucleic acid sequences involved in regulation of histone mRNA levels. These include DNA sequences involved in regulation of transcription and mRNA sequences involved in regulation of mRNA half-life. In particular, what are the differences in gene structure between the replication and replacement histone variants which differ in their regulation. We will answer this question by constructing variant genes, introducing them into cells and monitoring their regulatory behavior. In particular we will construct hybrid genes containing different portions of replication and replacement variant histones to see which portions are important in regulation. 2. What is the signal which regulates histone mRNA levels? The levels of histone mRNA are regulated by agents which alter deoxynucleotide metabolism. The hypothesis that an unusual nucleotide regulates histone mRNA levels will be tested. Changes in intracellular nucleotides which occur concominantly with alterations in histone mRNA levels will be analyzed. A cell-free system which may be used to assay for this signal will be developed. 3. Why is one cluster of histone genes on chromosome 3 expressed in 5 to 10 times the amount of the histone genes on chromosome 13? Genes will be constructed to test for the possibility of enhancer sequences on the histone genes on chromosome 3.