A Novel Sperm-Delivered Toxin Causes Late-Stage Embryo Lethality and Transmission Ratio Distortion in C. elegans
Figure 3
PEEL-1 localizes to fibrous body-membranous organelles.
(A) Diagram of spermatogenesis and fibrous body-membranous organelle (FB-MO) development, adapted with permission from [16]. FB-MOs develop in pachytene spermatocytes as membrane-bound organelles having a head region separated by a collar-like constriction from a set of membrane folds (lower panel; red). As spermatogenesis proceeds, the membrane folds grow and extend into arm-like protrusions, enveloping bundles of polymerized Major Sperm Protein, referred to as fibrous bodies (hatched region). Coincident with budding of spermatids from the residual body, the membrane folds of FB-MOs retract, and the fibrous bodies depolymerize into the cytoplasm. The FB-free MOs then move to a position just inside the plasma membrane, and upon sperm activation, they fuse with the plasma membrane opposite the pseudopod. (B–F) Nomarski and fluorescence images of spermatocytes and sperm expressing PEEL-1::GFP. Panels in (B) show the proximal arm of a male gonad, oriented with pachytene spermatocytes towards the left (bracketed region). Arrow and arrowhead indicate primary and secondary spermatocytes, respectively. Panels in (C–F) show higher resolution images of the following stages: secondary spermatocyte (C), budding spermatids (D), unactivated spermatid (E), and activated spermatozoan (F). (G–K) Spermatids were dissected from peel-1(+) (G–I) or peel-1(Δ) (J–K) males and stained with anti-PEEL-1 (green) and the FB-MO marker, 1CB4 (red) [64]. Nuclei are stained with DAPI (blue).