Fig. 5. Preventing PLC nuclear localisation permits Ca²⁺ oscillations during interphase. MII eggs were activated with Sr²⁺ in the presence of cytochalsin D. 2 hours after pronuclear formation the eggs were injected with Fura-dextran and Myc-PLC. (a) No Ca²⁺ transients were detected in these parthenotes (n=20). (b) Parallel parthenotes were also injected with WGA to block nuclear transport. In these embryos Myc-PLC triggered Ca²⁺ oscillations within 1 hour (n=20). Embryos were fixed and stained at the end of the experiment (as in Fig. 2) demonstrating that blocking nuclear pores with WGA, prevents import of PLC into the pronuclei (aii,bii). (c) Parthenotes were also injected with Myc-PLC^K377E (n=10). As with inhibiting nuclear import, preventing nuclear localisation of PLC through mutation of the NLS permitted Ca²⁺ oscillations during interphase. Such Ca²⁺ oscillations were not observed in parallel controls (n=10).