Silencing and reactivation of rRNA genes in Drosophila

果蝇，果蝇，是研究一些寄生虫基因如何复制到染色体上的新位点，在基因组中传播，以及生物物种如何对抗这些寄生虫的首要模型。核糖体是细胞中最重要的分子机器，由果蝇中的数百个基因编码，其中一些基因正在遭受遗传寄生虫的入侵，称为R1和R2反转录转座子。这些细胞有办法关闭这些基因，但在某些压力条件下，这些插入的基因又会被打开。这项拟议中的研究将研究这些基因从沉默转为活跃形式的机制。该项目的社会影响将介绍遗传学和细胞生物学的基本概念，在地区初中和高中代表性不足的学生，为代表性不足的高中生和本科生提供动手研究培训的机会，并培养研究生在先进的遗传学和细胞生物学。该项目还将确保为路易斯安那州立大学代表性不足的本科生和研究生提供持续的研究培训。在果蝇中有约400个核糖体RNA基因簇，其中约60%含有R1和/或R2反转录转座子的插入。R2元件天然存在于果蝇中约16%的rRNA基因的28 S区域内。这些插入的基因通常是沉默的，被认为是异染色质的，而剩余的活性非插入拷贝提供细胞所需的rRNA量。先前的研究结果表明，R2元件转录后的核仁压力所造成的损失核仁核糖体组装因子，Nopp 140。本项目研究了假定的转换与插入R2反转录转座子的rRNA基因从一个沉默的异染色质状态到一个活跃的常染色质状态时，核仁应力。将要回答的关键问题是去阻遏的R2是否与Pol I的额外28 S rRNA共线性表达，或者过度增强的R2表达是否独立于额外的rDNA单位表达。该项目将向巴吞鲁日地区初中和高中STEM代表性不足的学生介绍遗传学和细胞生物学的基本概念，为代表性不足的高中生和本科生提供动手研究培训的机会，并培训研究生以及高级遗传学和细胞生物学的高中教师。外联工作将包括在苏格兰维尔的初中和高中-一个贫困的，主要是非洲裔美国人的社区。初中、高中和本科培训的评估将采用预备性、形成性和总结性。

Fruit fly, Drosophila melanogaster, is a premier model to study how some parasitic genes copy themselves into the new sites in the chromosomes, spreading around the genome, and how living species counteract these parasites. Ribosome, the most important molecular machine in the cell, is encoded by several hundred genes in fruit fly, and some of these genes are suffering from the invasion of genetic parasites, known as R1 and R2 retrotransposons. The cells have a way of turning these genes off, but under some stress conditions, these inserted genes are turned back on. The proposed study will examine the mechanisms by which these genes switch from silent to active form. Social impacts of this project will introduce basic concepts in genetics and cell biology to underrepresented students in area middle and high schools, provide an opportunity for hands-on research training for underrepresented high school students and undergraduates, and train graduate students in advanced genetics and cell biology. This project will also ensure continued research training for underrepresented undergraduate and graduate students at Louisiana State University. There are ~400 ribosomal RNA gene clusters in Drosophila melanogaster, and ~60% of them contain insertions of R1 and/or R2 retrotransposons. R2 elements naturally reside within the 28S region of approximately 16% of the rRNA genes in Drosophila. These inserted genes are normally silent and are considered heterochromatic, while the remaining active non-inserted copies provide the required amount of rRNA for the cell needs. Previous results showed that R2 elements are transcribed upon nucleolar stress caused by the loss of the nucleolar ribosome assembly factor, Nopp140. This project examines the putative conversion of the rRNA genes with inserted R2 retrotransposons from a silent heterochromatic state to an active euchromatic state upon nucleolar stress. The key question that will be answered is whether de-repressed R2 is co-linearly expressed with extra 28S rRNA by Pol I, or excess enhanced R2 expression is independent of additional rDNA unit expression. This project will introduce basic concepts in genetics and cell biology to students from cohorts underrepresented in STEM in the Baton Rouge area middle and high schools, provide an opportunity for hands-on research training for underrepresented high school students and undergraduates, and train graduate students as well as high school teacher in advanced genetics and cell biology. Out-reach efforts will include middle and high schools in Scotlandville - a distressed, predominantly African-American neighborhood. Assessment of middle, high school, and undergraduate training will employ pre-, formative, and summative.