title: Dynamic distribution of Spatial during mouse spermatogenesis and its interaction with the kinesin KIF17b.
abstract: The Spatial gene is expressed in highly polarized cell types, such as epithelial cells in the thymus, neurons in the brain and germ cells in the testis. In this study, we report the characterization and distribution of Spatial proteins during mouse spermatogenesis. Besides Spatial-epsilon and -delta, we show that the newly described short isoform Spatial-beta is expressed specifically in round spermatids. Using indirect immunofluorescence, we detected Spatial in the cytosol of the early round spermatid. By the end stages of round spermatids, Spatial is concentrated at the opposite face of the acrosome near the nascent flagellum and in the manchette during the elongation process. Finally in mature sperm, Spatial persists in the principal piece of the tail. Moreover, we found that Spatial colocalizes with KIF17b, a testis-specific isoform of the brain kinesin-2 motor KIF17. This colocalization is restricted to the manchette and the principal piece of the sperm tail. Further, coimmunoprecipitation experiments of native proteins from testis lysates confirmed Spatial-KIF17b association through the long Spatial-epsilon isoform. Together, these findings imply a function of Spatial in spermatid differentiation as a new cargo of kinesin KIF17b, in a microtubule-dependent mechanism specific to the manchette and the principal piece of the sperm tail.
authors.affiliation: INSERM, ERM 206, Laboratoire tagc Case 928, Parc Scientifique de Luminy, 13288 Marseille Cedex 9, France.
authors.forename: Murielle
authors.initials: M
authors.lastname: Saade
authors.forename: Magali
authors.initials: M
authors.lastname: Irla
authors.forename: Jérôme
authors.initials: J
authors.lastname: Govin
authors.forename: Genevieve
authors.initials: G
authors.lastname: Victorero
authors.forename: Michel
authors.initials: M
authors.lastname: Samson
authors.forename: Catherine
authors.initials: C
authors.lastname: Nguyen
mesh_terms: D000818:Animals; D007150:Immunohistochemistry; D016547:Kinesins / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D020409:Molecular Motor Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms; D012671:Seminiferous Tubules / Q000378:metabolism; D013079:Sperm Maturation; D013091:Spermatogenesis; D013094:Spermatozoa / Q000378:metabolism*; D013737:Testis / Q000378:metabolism*
chemical_list: C409642:KIF17 protein, mouse; D020409:Molecular Motor Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; C419984:spatial protein, mouse; D016547:Kinesins