MicroRNA Let-7a and dicer are important in the activation and implantation of delayed implanting mouse embryos

STUDY QUESTION Does Let-7a have a functional role in modulating dicer expression to activate dormant mouse blastocysts for implantation? SUMMARY ANSWER Let-7a post-transcriptionally regulates dicer expression altering microRNA expression to affect the implantation competency of the activated blastocysts. WHAT IS KNOWN ALREADY The Let-7a microRNA is up-regulated during blastocyst dormancy and its forced-expression suppresses embryo implantation in vitro and in vivo. Dicer is a Let-7 target, which processes pre-microRNA to mature microRNA. STUDY DESIGN, SIZE, DURATION The effects on the expression of Let-7a and dicer in dormant blastocysts during the first 12 h after estradiol-induced activation, and the relationship between Let-7a and dicer in preimplantation embryos were determined. The effects on the microRNA expression and embryo implantation in vivo in dicer-knockdown mouse 5–8 cell embryos and dormant blastocysts at 1 h post estradiol activation were also studied. PARTICIPANTS/MATERIALS, SETTING, METHODS ICR female mice at 6 weeks of age were ovariectomized on Day 4 of pregnancy to generate the delayed implantation model. Mouse 5–8 cell embryos and/or dormant blastocysts at 1 h after estradiol injection were electroporated with dicer siRNA and Let-7a precursor or Let-7a inhibitor. At 48 h post electroporation, the Let-7a expression, dicer transcripts and proteins in the embryos were determined using qPCR and immunostaining/western blotting, respectively. A...
Source: Human Reproduction - Category: Reproduction Medicine Authors: Tags: Reproductive biology Source Type: research