title: Nuclear envelope remodelling during human spermiogenesis involves somatic B-type lamins and a spermatid-specific B3 lamin isoform.
abstract: The nuclear lamina (NL) is a filamentous protein meshwork, composed essentially of lamins, situated between the inner nuclear membrane and the chromatin. There is mounting evidence that the NL plays a role in spermatid differentiation during spermiogenesis. The mouse spermatid NL is composed of the ubiquitous lamin B1 and the spermatid-specific lamin B3, an N-terminally truncated isoform of lamin B2. However, nothing is known about the NL in human spermatids. We therefore investigated the expression pattern and localization of A-type lamins (A, C and C2) and B-type lamins (B1, B2 and B3) during human spermiogenesis. Here, we show that a lamin B3 transcript is present in human spermatids and that B-type lamins are the only lamins detectable in human spermatids. We determine that, as shown for their mouse counterparts, human lamin B3, but not lamin B2, induces strong nuclear deformation, when ectopically expressed in HeLa cells. Co-immunofluorescence revealed that, in human spermatids, B-type lamins are present at the nuclear periphery, except in the region covered by the acrosome, and that as the spermatid matures the B-type lamins recede towards the posterior pole. Only lamin B1 remains detectable on 33-47% of ejaculated spermatozoa. On spermatozoa selected for normal head density, however, this fell to <6%, suggesting that loss of the NL signal may be linked to complete sperm nucleus compaction. The similarities revealed between lamin expression during human and rodent spermiogenesis, strengthen evidence that the NL and lamin B3 have conserved functions during the intense remodelling of the mammalian spermatid nucleus.
authors.affiliation: Aix Marseille Université, INSERM, GMGF UMR_S 910, 13385, Marseille, France.
authors.forename: Razan
authors.initials: R
authors.lastname: Elkhatib
authors.affiliation: Aix Marseille Université, INSERM, GMGF UMR_S 910, 13385, Marseille, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Longepied
authors.affiliation: Aix Marseille Université, INSERM, GMGF UMR_S 910, 13385, Marseille, France APHM Hôpital La Conception, Gynépôle, Laboratoire de Biologie de la Reproduction-CECOS, 13385 Marseille Cedex 5, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Paci
authors.affiliation: APHM Hôpital La Conception, Gynépôle, Laboratoire de Biologie de la Reproduction-CECOS, 13385 Marseille Cedex 5, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Achard
authors.affiliation: APHM Hôpital La Conception, Gynépôle, Laboratoire de Biologie de la Reproduction-CECOS, 13385 Marseille Cedex 5, France Aix Marseille Université, Laboratoire de Biogénotoxicologie et Mutagenèse Environnementale, EA 1784 - Fédération de Recherche CNRS no 3098 Ecosystèmes Continentaux et Risques Environnementaux, 13385 Marseille Cedex 5, France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Grillo
authors.affiliation: Aix Marseille Université, INSERM, GMGF UMR_S 910, 13385, Marseille, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Levy
authors.affiliation: Aix Marseille Université, INSERM, GMGF UMR_S 910, 13385, Marseille, France.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mitchell
authors.affiliation: Aix Marseille Université, INSERM, GMGF UMR_S 910, 13385, Marseille, France APHM Hôpital La Conception, Gynépôle, Laboratoire de Biologie de la Reproduction-CECOS, 13385 Marseille Cedex 5, France catherine.metzler-guillemain@univ-amu.fr.
authors.forename: Catherine
authors.initials: C
authors.lastname: Metzler-Guillemain
mesh_terms: D000177:Acrosome / Q000378:metabolism / Q000648:ultrastructure; D000328:Adult; D000818:Animals; D002454:Cell Differentiation; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D034904:Lamin Type A / Q000235:genetics / Q000378:metabolism; D034921:Lamin Type B / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D034881:Nuclear Lamina / Q000378:metabolism* / Q000648:ultrastructure; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D013087:Spermatids / Q000378:metabolism / Q000648:ultrastructure; D013091:Spermatogenesis / Q000235:genetics*
chemical_list: C494847:LMNA protein, human; D034904:Lamin Type A; D034921:Lamin Type B; D020033:Protein Isoforms; D012333:RNA, Messenger
keywords: human; lamins; nuclear lamina; spermiogenesis