Cellular Functions of Nopp140 Splice Variants in Drosophila

细胞核仁的主要功能是组装核糖体，核糖体随后从细胞核移动到细胞质，在那里它们催化细胞各种蛋白质的合成。 核糖体组装是一系列复杂的生物合成反应，从基因水平开始，以具有合成功能的核糖体结束，每个核糖体由4个RNA分子和80种不同的蛋白质组成。 因此，核糖体组装是基因表达的综合范例。 核糖体生物合成的破坏导致致死或发育异常。这个研究项目的目标是建立一个分子遗传学的方法来了解核仁特异性蛋白质如何帮助组装核糖体在多细胞生物。 本计画探讨果蝇中两个密切相关的核仁蛋白质的功能。 这两种蛋白质由相同的基因编码，但转录本在果蝇细胞中的加工方式不同，导致两种蛋白质变体。 其中一种变体与脊椎动物核仁蛋白Nopp 140非常相似，这种蛋白的功能未知。 果蝇的另一个变体是独特的;它与所有已知的脊椎动物Nopp 140蛋白质的不同之处在于，Nopp 140的正常尾端被许多RNA结合蛋白质中发现的肽结构域所取代。 该项目将定义两种果蝇Nopp 140变体的发育和组织特异性表达模式。 转基因技术也将用于构建一种或两种Nopp 140变异体都受到破坏的突变果蝇。 Nopp 140基因破坏的影响将通过细胞学和生物化学技术相结合的方式进行评估。该项目将涉及本科生和研究生，并将特别努力招募少数民族学生参加该项目。 在这项研究的过程中，学生将获得现代遗传学，细胞学和生物化学的经验。

The primary function of the cell nucleolus is to assemble ribosomes that subsequently move from the nucleus to the cytoplasm, where they catalyze the synthesis of the cell's various proteins. Ribosome assembly is a complex series of biosynthetic reactions that begins at the gene level and ends with synthetically functional ribosomes, each of which consists of four RNA molecules and 80 different proteins. Ribosome assembly is thus a comprehensive paradigm for gene expression. Disruption of ribosome biosynthesis leads to lethality or developmental abnormalities. The goals of this research project are to establish a molecular-genetic approach toward understanding how nucleolar-specific proteins help assemble ribosomes in multicellular organisms. This project examines the functions of two closely-related nucleolar proteins in the fruitfly Drosophila melanogaster. Both proteins are encoded by the same gene, but the transcripts are processed differently in Drosophila cells, resulting in two protein variants. One of the two variants is very similar to a vertebrate nucleolar protein of unknown function called Nopp140. The other Drosophila variant is unique; it differs from all known vertebrate Nopp140 proteins in that the normal tail end of Nopp140 is replaced by a peptide domain found in many RNA-binding proteins. The project will define the developmental and tissue-specific expression patterns of the two Drosophila Nopp140 variants. Transgenic techniques will also be used to construct mutant flies with disruptions in either one or both Nopp140 variants. The effects of Nopp140 gene disruptions will be assessed by a combination of cytological and biochemical techniques.The project will involve both undergraduate and graduate students, and special effort will be made to recruit minority students to the project. In the course of this research, students will gain experience in modern genetics, cytology and biochemistry.