Several studies have linked assisted reproductive technologies to aberrant imprinting. We previously showed that 12-day in vitro follicle culture supports normal imprinting establishment in mouse oocytes. The aim of the present study was to assess whether shortened in vitro follicle growth (8 days of culture compared with 12 days, as a model for human in vitro maturation) or preovulatory intrafollicular oocyte “aging” in culture (14 days of culture) leads to imprinting mutations in oocytes. Limiting-dilution bisulphite sequencing showed that shortened in vitro follicle growth (8 days) does not induce oocyte epimutations at the imprinted Snrpn and Mest genes. In contrast, extension of oocyte residence in large unluteinized follicles in vitro was associated with a low level (1 of 54 alleles) of epimutations for Mest but not for Snrpn. The latter condition may occur during controlled ovarian stimulation where the oocyte growth phase may be extended for several days. Furthermore, we studied the dynamics during follicle culture of transcript levels for genes previously shown to be essential for imprinting establishment in oocytes, including Dnmt3a, Dnmt3L, and Zfp57. Oocyte total mRNA levels during in vitro follicle culture showed the timely shutdown in transcription at the antral follicle stage, and total mRNA levels were comparable to those of in vivo grown equine chorionic gonadotropin-stimulated oocytes.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 89 • No. 6