CONTROL OF HISTONE MRNA SYNTHESIS

组蛋白mRNA浓度与DNA合成平行调节。 有两类组蛋白mRNA;主要的一类是受调节的 和复制组蛋白变体的代码，以及一个小类， 由替换组蛋白变体的代码组成型表达。 的 组蛋白mRNA水平在细胞周期中受到调节， 可能与调节DNA和组蛋白合成有关。 三大 将讨论以下问题：1。核酸序列是什么 参与组蛋白mRNA水平的调节。 其中包括DNA序列 参与转录调控的mRNA序列 mRNA半衰期的调节。 具体来说， 复制和替换组蛋白变体之间的基因结构 它们的规则不同。 我们将通过以下方式回答这个问题： 构建变异基因，将其导入细胞并监测 他们的监管行为。 特别是我们将构建杂交基因 含有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.是什么 调节组蛋白mRNA水平的信号？ 组蛋白mRNA的水平是 由改变脱氧核苷酸代谢的试剂调节。 的假设 一个不寻常的核苷酸调节组蛋白mRNA水平将被测试。 细胞内核苷酸的变化， 将分析组蛋白mRNA水平的改变。 无细胞系统 将开发可用于测定该信号的方法。 3.为什么 3号染色体上的一簇组蛋白基因表达量是正常人的5到10倍， 13号染色体上的组蛋白基因数量 基因将被构建成 测试组蛋白基因上增强子序列的可能性， 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.