CARCINOGENS AND CHROMATIN STRUCTURE AND FUNCTION

致癌物和染色质结构与功能

• 批准号: 3166826
• 负责人: MARK E SMULSON
• 金额: $ 17.53万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-06-01 至 1995-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3166826
• 关键词: ADP ribosylation; DNA directed DNA polymerase; DNA repair; DNA replication; RNA splicing; antisense nucleic acid; chemical carcinogen; enzyme mechanism; enzyme structure; flow cytometry; genetic transcription; human tissue; molecular cloning; nicotinamide adenine dinucleotide; nucleoproteins; nucleosomes; plasmids; protein structure function; ribosomal RNA; ribozymes; tissue /cell culture; transfection; transposon /insertion element

The poly ADP-ribosylation modification of nuclear proteins is the initial cellular response to DNA damage caused by chemicals. Poly(ADP-ribose) polymerase (PADPRP) catalytic activity is absolutely dependent upon DNA and its activity is directly correlated with the number of strand breaks in DNA. Thus, when cells, are exposed to chemical carcinogens, there is an immediate drop in cellular NAD and concomitant rapid and transient increase in poly ADP-ribosylated nuclear proteins. Recent progress on this project involved the cloning, sequencing, and hyperexpression of transfected genes for this enzyme in both human and murine systems. Preliminary data using transient transfection indicated that cells hyperexpressing PADPRP have increased rates of DNA repair. We also were able to map the precise chromosomal loci for this gene in both human and mouse. During the renewal period, we intent to utilize the molecular and biochemical data obtained to better clarify and characterize the role of ADP-ribosylation in DNA repair mechanisms. Methods in Aim I utilize a variety of molecular approaches including antisense and ribozyme expression, to experimentally modulate ADP-ribosylation potential in cells subjected to DNA strand breaks and assess the effects of this by utilizing new methods for precisely measuring preferential gene repair and recombinase activity using novel plasmid assays. Nuclear targets for ADP ribosylation are the focus of Aim II. The new molecular information will be used here to relate structure of PADPRP (and its nuclear protein acceptors) to function. For example, c-fos is a nuclear acceptor for PADPRP and also transcriptionally activated by strand- breaking chemicals. PADPRP activity modulated by antisense will be used to address the biological function of the PADPRP of fos, and as an example of approaches to be used for other nuclear protein acceptors during the renewal period.

核蛋白的聚adp核糖基化修饰是最初的