MAIZE RIBOSOMAL PROTEIN GENE STRUCTURE AND EXPRESSION

拟议研究的长期目标是 了解基因结构与基因表达的关系; 细胞调节大量基因的表达， 功能质体（70 S）和胞质（80 S）核糖体;以及 质体和核编码的70 S核糖体蛋白的表达 基因在独立的基因组中协调。 大量增加 70 S和80 S核糖体的细胞内容物发生在玉米 叶细胞发育 具体目标是彻底 表征整个玉米叶中的核糖体含量; 测定80 S、质体编码和核- 利用核糖体基因组技术在叶片中编码70 S核糖体蛋白mRNA 蛋白质cDNA作为杂交探针;并检查 核糖体蛋白质合成的关键。 另夕h 70 S核糖体含量对核表达的影响 编码的70 S核糖体蛋白基因表达将在 玉米的突变体，这些突变体对低温敏感， 70 S核糖体 这些实验旨在确定 70 S平衡积累的机制 核糖体蛋白 作为对上述研究的补充， 80 S和核编码的70 S核糖体蛋白基因结构。 使用异源70 S和80 S分离这些基因的cDNA 核糖体蛋白cDNA。 然后将玉米cDNA用于 上述实验，并选择基因组克隆从一个 玉米图书馆 几个80 S和核编码的70 S核糖体 蛋白质基因将被测序。 转录开始和停止 将通过S1核酸酶图谱和引物鉴定位点 可拓分析 计算机辅助序列分析这些 基因可以揭示可能参与癌症的DNA序列， 核糖体蛋白基因的协调调节。 蛋白 基因的结合活性将通过DNA足迹来检查 分析. 此外，一些核糖体 蛋白质与前mRNA或成熟mRNA的结合将通过 蛋白质-RNA结合测定。

The long-term objectives of the proposed research are to understand how gene structure relates to gene expression; how the cell regulates the expression of large sets of genes to produce functional plastid (70S) and cytosolic (80S) ribosomes; and how the expression of plastid- and nuclear-encoded 70S ribosomal protein genes is coordinated in the separate genomes. A large increase in the cellular content of 70S and 80S ribosomes occurs during maize leaf cell development. The specific aims are to thoroughly characterize the ribosome content throughout maize leaves; determine the content of 80S and plastid-encoded and nuclear- encoded 70S ribosomal protein mRNAs in leaves using ribosomal protein cDNAs as hybridization probes; and to examine the rates of ribosomal protein synthesis in the leaves. Additionally, the influence of 70S ribosome content on the expression nuclear- encoded 70S ribosomal protein gene expression will be studied in mutants of maize which pre cold-sensitive for the accumlation of the 70S ribosomes. These experiments are designed to determine the mechanisms leading to the balanced accumulation of 70S ribosomal proteins. Complementary to the above studies will be the investigation of 80S and nuclear-encoded 70S ribosomal protein gene structure. cDNAs for these genes be isolated using heterologous 70S and 80S ribosomal protein cDNAs. The maize cDNAs will then be used in the above experiments and to select the genomic clones from a maize library. Several 80S and nuclear-encoded 70S ribosomal protein genes will be sequenced. Transcription start and stop sites will be identified by S1 nuclease mapping and primer extension analysis. Computer-assisted sequence analysis of these genes may reveal DNA sequences that could be involved in the coordinate regulation of the ribosomal protein genes. Protein binding activity of the genes will be examined by DNA footprint analysis. Additionally, the possibility that some ribosomal proteins bind to pre-mRNAs or mature mRNAs will be tested by protein-RNA binding assays.