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. 2015 Feb 11;92(3):80. doi: 10.1095/biolreprod.114.123661

FIG. 7.

FIG. 7

Nuclear shaping defects in Parp11 knockout spermatids. TEM analyses of elongating spermatids in Parp11+/+ and Parp11−/− testes confirm that wild-type Parp11+/+ early elongating spermatid present with normal structures typical of this developmental step. A) The electron-dense nuclear dense lamina (ndl) coats the nuclear envelope in the entire subacrosomal area. Extranuclear shaping structures are shown in the enlarged insets. Inset 1) F-actin rings inside the surrounding Sertoli cell (Sert) above the developing flat acrosomal area (ac) are visible as dark dots (F). The marginal ring of the acroplaxome (mr) marks the transitional region between the developing acrosome and the manchette (mc). Inset 2) The manchette is comprised of straight microtubule filaments (mt) that surround the central part of the nucleus (n). Nuclear pores (np) are located mainly at the distal end of the nucleus. B) Parp11−/− spermatid. The same basic shaping structures (manchette, F-actin rings, flat developing acrosome and acroplaxome [insets 2 and 4]) are also present in Parp11−/− spermatids of the same developmental step. However, in contrast to the wild-type, the nuclear dense lamia (ndl) coating the subacrosomal nuclear envelope appears interrupted at several positions in subacrosomal regions (arrows in Insets 1 [adjacent other spermatid] and Inset 3 [central region]) as well as under the marginal ring of the acroplaxome (Inset 2). C) Later stage (i.e., more elongated) Parp11+/+ (left) and Parp11−/− spermatids (right). Whereas formation of manchette (Inset 1) and marginal ring (mr; dotted line box in Inset 3) and caudal localization of nuclear pores (np; Inset 2) again appears normal in the Parp11+/+ spermatids, an abnormal invagination of the nuclear envelope (ne) into the nuclear lumen is apparent (arrow in oval of Inset 2). D and E) Round Parp11−/− spermatids have areas of abnormal separation of the nuclear envelope membranes from each other (D, inset 1, and E, inset 1) and detachment of the chromatin from the nuclear envelope (E, insets 2 and 3). adn, acrosome dense plaque. Bar = 500 nm.