Fig. 1. Maternal Dkk1 is ubiquitously expressed. (A) Control uninjected (uninj.) and sibling antisense oligo (AS1 5 ng)-injected oocytes were frozen as mature oocytes, mid- (stage 8.5), early (stage 10.5) and late gastrula (stage 12) stage oocytes, and assayed by real-time RT-PCR for the relative expression of Dkk1 mRNA. (B) Batches of two whole and four animal- or four vegetal-half uninjected stage 6 oocytes were assayed by real-time RT-PCR for the relative expression of VegT and Dkk1 mRNA. (C) Batches of two whole and four right-, left-, dorsal- or ventral-half four-cell stage embryos were assayed by real-time RT-PCR for the relative expression of Dkk1 mRNA. (D) Control uninjected (uninj.) and sibling antisense oligo (AS1 5 ng, 10 ng)-injected oocytes were frozen after 48 hours in culture as mature oocytes and assayed for maternal Dkk1 mRNA expression.