Fig. 2.

Tssk6 is required for fertilization but not for egg activation. Sperm were obtained from either WT or Tssk6-null mice and used for in vitro fertilization assays as described in the Materials and Methods. (A) Representative images showing WT eggs with (IVF) or without zona pellucida (IVF-Zona Free) after 4 hours of IVF. Note the formation of the two pronuclei in the eggs fertilized with WT sperm (arrows) and the absence of fertilization in the eggs that were exposed to Tssk6-null sperm (KO). The lower panels (ICSI) depict characteristic intracellular Ca²⁺ transients, indicating equivalent egg activation in the eggs injected with the WT and Tssk6-null sperm. (B) Quantification of the experimental data from A. The data represent a combination of at least four independent experiments and are presented as a percentage of the total eggs used. The total number of eggs used is indicated atop each column.