title: The spinal muscular atrophy protein SMN affects Drosophila germline nuclear organization through the U body-P body pathway.
abstract: Survival motor neuron protein (SMN) is the determining factor for the human neurodegenerative disease spinal muscular atrophy (SMA). SMN is critical for small nuclear ribonucleoprotein (snRNP) assembly. Using Drosophila oogenesis as a model system, we show that mutations in smn cause abnormal nuclear organization in nurse cells and oocytes. Germline and mitotic clonal analysis reveals that both nurse cells and oocytes require SMN to maintain normal organization of nuclear compartments including chromosomes, nucleoli, Cajal bodies and histone locus bodies. We previously found that SMN-containing U bodies invariably associate with P bodies (Liu, J. L., and Gall, J. G. (2007). U bodies are cytoplasmic structures that contain uridine-rich small nuclear ribonucleoproteins and associate with P bodies. Proc. Natl. Acad. Sci. U. S. A. 104, 11655-11659.). Multiple lines of evidence implicate SMN in the regulation of germline nuclear organization through the connection of U bodies and P bodies. Firstly, smn germline clones phenocopy mutations for two P body components, Cup and Ovarian tumour (Otu). Secondly, P body mutations disrupt SMN distribution and the organization of U bodies. Finally, mutations in smn disrupt the function and organization of U bodies and P bodies. Taken together, our results suggest that SMN is required for the functional integrity of the U body-P body pathway, which in turn is important for maintaining proper nuclear architecture.
authors.affiliation: Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, Henry Wellcome Building for Gene Function, University of Oxford, Oxford OX1 3QX, UK.
authors.forename: Lin
authors.initials: L
authors.lastname: Lee
authors.forename: Siân E
authors.initials: SE
authors.lastname: Davies
authors.forename: Ji-Long
authors.initials: JL
authors.lastname: Liu
mesh_terms: D000818:Animals; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D002999:Clone Cells; D020541:Coiled Bodies / Q000378:metabolism; D022083:Cytoplasmic Structures / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000378:metabolism*; D005854:Germ Cells / Q000166:cytology* / Q000378:metabolism; D006570:Heterochromatin / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D008938:Mitosis; D008954:Models, Biological; D009134:Muscular Atrophy, Spinal / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D021381:Protein Transport; D012342:RNA, Small Nuclear / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D006570:Heterochromatin; D006657:Histones; D012342:RNA, Small Nuclear; D016601:RNA-Binding Proteins; C542563:Smn protein, Drosophila; C405484:U2 small nuclear RNA; C105238:cup protein, Drosophila; C061992:otu protein, Drosophila