Figure 3. Precursor of let-7 inhibits embryo implantation in vivo.

Eight-cell embryos were electroporated with precursor of let-7a or control RNA, and transferred into opposite uterine horns of mice on Day 3 of pseudopregnancy (5 embryos for each horn). Let-7a reduced the number of embryos implanted in the uterus. Statistical significant difference (P<0.05, Chi square) in the number of implantation sites was found on Day-8 of pregnancy (n = 18).