title: Drosophila germ granules are structured and contain homotypic mRNA clusters.
abstract: Germ granules, specialized ribonucleoprotein particles, are a hallmark of all germ cells. In Drosophila, an estimated 200 mRNAs are enriched in the germ plasm, and some of these have important, often conserved roles in germ cell formation, specification, survival and migration. How mRNAs are spatially distributed within a germ granule and whether their position defines functional properties is unclear. Here we show, using single-molecule FISH and structured illumination microscopy, a super-resolution approach, that mRNAs are spatially organized within the granule whereas core germ plasm proteins are distributed evenly throughout the granule. Multiple copies of single mRNAs organize into 'homotypic clusters' that occupy defined positions within the center or periphery of the granule. This organization, which is maintained during embryogenesis and independent of the translational or degradation activity of mRNAs, reveals new regulatory mechanisms for germ plasm mRNAs that may be applicable to other mRNA granules.
authors.affiliation: Department of Cell Biology, HHMI, Skirball Institute of Biomolecular Medicine, NYU School of Medicine, 540 First Avenue, New York, New York 10016, USA.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Trcek
authors.affiliation: Department of Cell Biology, HHMI, Skirball Institute of Biomolecular Medicine, NYU School of Medicine, 540 First Avenue, New York, New York 10016, USA.
authors.forename: Markus
authors.initials: M
authors.lastname: Grosch
authors.affiliation: Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, NIH, BG 13 RM G800, 13 South Dr, Bethesda, Maryland 20814, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: York
authors.affiliation: Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, NIH, BG 13 RM G800, 13 South Dr, Bethesda, Maryland 20814, USA.
authors.forename: Hari
authors.initials: H
authors.lastname: Shroff
authors.affiliation: Transcription Imaging Consortium, Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, USA.
authors.forename: Timothée
authors.initials: T
authors.lastname: Lionnet
authors.affiliation: Department of Cell Biology, HHMI, Skirball Institute of Biomolecular Medicine, NYU School of Medicine, 540 First Avenue, New York, New York 10016, USA.
authors.forename: Ruth
authors.initials: R
authors.lastname: Lehmann
mesh_terms: D000818:Animals; D003594:Cytoplasmic Granules / Q000378:metabolism*; D004330:Drosophila / Q000378:metabolism*; D005854:Germ Cells / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger