Send to

Choose Destination
See comment in PubMed Commons below
J Vet Med Sci. 1998 Jul;60(7):791-4.

A delayed-implantation-associated protein prevents resumption of DNA synthesis by the trophectoderm of delayed-implanting mouse blastocysts in vitro.

Author information

Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.


Objective of this study was to determine the ability of a delayed-implantation-associated protein (MW 170,000, DIAP170K) to inhibit DNA synthesis by mouse blastocysts. Mice were ovariectomized on day 3 of pregnancy and treated with daily injections with 1 mg progesterone till day 7 to induce delayed implantation. Blastocysts were collected on day 8 with or without a single injection of 25 ng estradiol-17 beta on day 7 that activates blastocyst metabolisms (activated blastocysts and delayed-implanting blastocysts respectively). DNA synthesis was determined by measuring [3H]thymidine incorporation by blastocysts. DIAP170K at 10 micrograms/m/ suppressed resumption of DNA synthesis by delayed-implanting blastocysts and suppression was maximal at 50 micrograms/m/. However, DIAP170K did not affect DNA synthesis by blastocysts obtained on day 5 of pregnancy (normal blastocysts) and activated blastocysts. Resumption of DNA synthesis in the inner cell mass (ICM) and trophectoderm from delayed-implanting blastocysts was then separately assessed. DNA synthesis resumed in the trophectoderm of intact blastocysts during 24-hr culture but not in the trophectoderm cultured apart from the ICM. DIAP170K inhibited the resumption of DNA synthesis by the trophectoderm of intact delayed-implanting blastocysts but did not affect DNA synthesis by the ICM. In conclusion, DIAP170K inhibits resumption of DNA synthesis by trophectoderm of delayed-implanting blastocysts. This action of DIAP170K may play a central role in maintaining, but not achieving, dormancy of DNA synthesis by delayed-implanting blastocysts in mice.

[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for J-STAGE, Japan Science and Technology Information Aggregator, Electronic
    Loading ...
    Support Center