title: Bucky ball organizes germ plasm assembly in zebrafish.
abstract: In many animals, gamete formation during embryogenesis is specified by maternal cytoplasmic determinants termed germ plasm. During oogenesis, germ plasm forms a distinct cellular structure such as pole plasm in Drosophila or the Balbiani body, an aggregate of organelles also found in mammals. However, in vertebrates, the key regulators of germ plasm assembly are largely unknown. Here, we show that, at the beginning of zebrafish oogenesis, the germ plasm defect in bucky ball (buc) mutants precedes the loss of polarity, indicating that Buc primarily controls Balbiani body formation. Moreover, we molecularly identify the buc gene, which is exclusively expressed in the ovary with a novel, dynamic mRNA localization pattern first detectable within the Balbiani body. We find that a Buc-GFP fusion localizes to the Balbiani body during oogenesis and with the germ plasm during early embryogenesis, consistent with a role in germ plasm formation. Interestingly, overexpression of buc seems to generate ectopic germ cells in the zebrafish embryo. Because we discovered buc homologs in many vertebrate genomes, including mammals, these results identify buc as the first gene necessary and sufficient for germ plasm organization in vertebrates.
authors.affiliation: Department of Zoology, University of Geneva, 1211 Geneva 4, Switzerland.
authors.forename: Franck
authors.initials: F
authors.lastname: Bontems
authors.forename: Amandine
authors.initials: A
authors.lastname: Stein
authors.forename: Florence
authors.initials: F
authors.lastname: Marlow
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Lyautey
authors.forename: Tripti
authors.initials: T
authors.lastname: Gupta
authors.forename: Mary C
authors.initials: MC
authors.lastname: Mullins
authors.forename: Roland
authors.initials: R
authors.lastname: Dosch
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016764:Cell Polarity; D005260:Female; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D009866:Oogenesis / Q000502:physiology*; D010053:Ovary / Q000166:cytology / Q000378:metabolism; D010802:Phylogeny; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015027:Zebrafish / Q000033:anatomy & histology / Q000196:embryology*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D011993:Recombinant Fusion Proteins; D029961:Zebrafish Proteins; C541253:buc protein, zebrafish