GENETIC AND MOLECULAR STUDIES OF GROUP II INTRONS

II 组内含子的遗传和分子研究

• 批准号: 6329639
• 负责人: PHILIP S. PERLMAN
• 金额: $ 35.16万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-08-01 至 2003-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6329639
• 关键词: RNA binding protein; RNA directed DNA polymerase; RNA splicing; Saccharomyces; complementary DNA; endonuclease; fungal genetics; gene mutation; genetic recombination; introns; laboratory rabbit; mitochondria; mitochondrial DNA; monoclonal antibody; nucleic acid sequence; open reading frames; precursor mRNA; protein structure function

Splicing and genetic properties of group II introns will be investigated in mitochondria of bakers yeast, Saccharomyces cerevisiae. Introns I and 2 of the COXI gene of mtDNA code for a protein with reverse transcriptase (RT), endonuclease and maturase (splicing) functions essential for the splicing and homing/transposition by the introns. Both introns are highly efficient, site-specific retroelements clearly related to non-LTR- retrotransposons, including the LINE elements of the human genome. Major and minor intron homing pathways have been identified, all of which depend on a remarkable reaction in which a complex containing the intron-encoded RT and excised intron RNA lariat inserts the intron RNA into the sense strand of the intron-less DNA target site by a reverse splicing reaction. Subsequent steps vary widely among various RT- independent pathways. Bakers yeast has numerous attributes that make it a powerful and facile system for research on mechanisms of group II intron homing, and for the mechanisms of site-specific homing by group II introns to obtain a clear view of how the various pathways differ and, or importantly, to show how a common homing intermediate is partitioned among processes, transposition was likely a mechanism by which introns spread during evolution. A system will be developed to detect retrotransposition of a tagged intron from mitochondria to the nucleus. The third aim is to characterize aspects of group II intron molecular biology. The main emphasis is to identify nuclear will analyze genes that process the precursor to the intron-encoded RT, control the stability and degradation of excised group II intron RNAs, and assist the self-splicing of the introns. Finally, the RNA binding and splicing functions of the naturase domain of the intron-encoded protein will be studied.

研究面包酵母（Saccharomyces cerevisiae）线粒体中II族内含子的剪接和遗传特性。mtDNA COXI基因的内含子I和2编码一种蛋白质，该蛋白质具有逆转录酶（RT）、核酸内切酶和成熟酶（剪接）功能，这些功能对于内含子的剪接和归巢/转位至关重要。这两个内含子都是高效的、特异位点的逆转录因子，与非ltr逆转录转座子明显相关，包括人类基因组的LINE元件。主要和次要的内含子归巢途径已经被确定，所有这些途径都依赖于一个显著的反应，在这个反应中，内含子编码的RT和切除的内含子RNA通过反向剪接反应将内含子RNA插入到无内含子DNA靶位点的意义链中。随后的步骤在各种与RT无关的途径中差别很大。baker酵母具有许多特性，使其成为研究II族内含子归巢机制的强大而便捷的系统，以及II族内含子的位点特异性归巢机制，以获得各种途径如何不同的清晰观点，或者重要的是，显示一个共同的归巢中间体如何在过程中分配，转位可能是内含子在进化过程中传播的一种机制。将开发一种系统来检测标记内含子从线粒体到细胞核的反转录转位。第三个目的是表征第二组内含子分子生物学的各个方面。主要重点是鉴定核将分析处理内含子编码RT前体的基因，控制切除的II组内含子rna的稳定性和降解，并协助内含子的自剪接。最后，将研究内含子编码蛋白的自然酶结构域的RNA结合和剪接功能。