Fig. 6

bucky ball limits the micropylar follicle cell fate preventing polyspermy. (A, E) The single micropyle (pink circle) at the animal pole of a wild-type chorion. (B, F) Multiple micropyles on buc chorions (pink circles). (C) An oocyte cytoplasmic projection extends from the plasma membrane to the micropyle in activated wild-type oocytes (arrowhead). (D) Multiple projections in activated buc mutant oocytes (arrowheads). (G) In activated wild-type eggs, Actin is enriched at the animal pole cortex. (H) In activated buc eggs, Actin is uniform around the cortex due to the lack of animal–vegetal polarity. (I) Actin and DAPI label the extruded polar body (pb), while DAPI alone marks the female pronucleus (pn), indicating the completion of meiosis in unfertilized wild-type. (J) Like wild-type a single pronucleus and polar body are observed in activated buc mutants. (G, H) Yellow boxed areas indicate regions depicted in panels I and J. (L) Female and male pronuclei in a wild-type egg 10 mpf. (K, M) Polyspermy is indicated by excess pronuclei (yellow circles in panel K) in buc mutant eggs 10 mpf. (N) DAPI staining showing cleavage occurs at the animal pole in wild-type (blue arrow), while nuclear cleavage (O) is circumferential in buc progeny (blue arrows). (A–F) Live dissecting microscope images. (G, H) 10x confocal objective. (I, J) Confocal images 63x objective. (K) Dissecting microscope image; (L, M) 40x acquired images. (N, O) Images 5x objective. Scale bars are 200 μm except for panels I, J, L, M which are 10 μm.