The disclosure is directed to methods for improving the quality of oocytes for assisted reproductive technology procedures (ARTs), such as oocyte cryopreservation and in vitro fertilization. The method involves culturing an oocyte in which endogenous expression of miRNAs miR-20b, miR-199, and miR-363 is absent or reduced in the presence of exogenous miR-20b, miR-199, and miR-363. The disclosure also provides methods for selecting high-quality oocytes by assessing expression of the miRNAs miR-20b, miR-199, and miR-363 in a cumulus cell surrounding an oocyte isolated from a subject, and methods for performing an ART procedure using a selected high-quality oocyte.

Provided is a method for culturing immature oocytes. The method can promote in vitro maturation of the immature oocytes, and specifically comprises using follicular cells and a culture medium for culturing same. The culture medium for culturing the follicular cells contains CNP or variants thereof or analogues thereof and an HDAC (histone deacetylase) inhibitor. Also provided are the in vitro maturation culture medium containing CNP or variants thereof or analogues thereof and the HDAC inhibitor, and related compositions thereof, and the use of the above medium, culture medium and compositions in the promotion of in vitro maturation of the immature oocytes.

Methods of enhancing fertility of a female subject by increasing the number of oogonia present in the ovary of the female subject are provided. Aspects of the methods include methods of in vivo expansion of oogonia as well as methods of ex vivo expansion of oogonia.

The present invention relates to a method for vitrification and thawing of oocytes of animals for somatic cell cloning. More specifically, the present disclosure relates to a method for vitrification and thawing of canine oocytes, and to thus produced frozen-thawed oocytes. In a conventional approach of the vitrification-frozen oocyte production for the dog, an estrous cycle may not coincide with an experimental schedule. However, the method for vitrification and thawing of the canine oocyte according to the present disclosure and the resulting frozen-thawed oocyte allows an experimental schedule to coincide with the estrous cycle, resulting in high nuclear transfer and fertilization effects.

A method of providing a culture of oogonia stem cells comprising oogonia stem cells is provided. The method may further include culturing the oogonia stem cells with granulosa and theca cells to differentiate the oogonia stem cells into oocytes. In some embodiments, the culturing comprises including the oogonia stem cells in an in vitro follicle construct or a microcapsule comprising said granulosa and theca cells. Further described herein is a method of forming a bioengineered follicle construct capable of releasing a mature oocyte. An in vitro fertilization method using the mature oocyte is also provided.

The present invention relates to a nucleic acid molecule encoding (I) a polypeptide having the activity of an endonuclease, which is (a) a nucleic acid molecule encoding a polypeptide comprising or consisting of the amino acid sequence of SEQ ID NO: 1; (b) a nucleic acid molecule comprising or consisting of the nucleotide sequence of SEQ ID NO: 2; (c) a nucleic acid molecule encoding an endonuclease, the amino acid sequence of which is at least 70% identical to the amino acid sequence of SEQ ID NO: 1; (d) a nucleic acid molecule comprising or consisting of a nucleotide sequence which is at least 50% identical to the nucleotide sequence of SEQ ID NO: 2; (e) a nucleic acid molecule which is degenerate with respect to the nucleic acid molecule of (d); or (f) a nucleic acid molecule corresponding to the nucleic acid molecule of any one of (a) to (e) wherein T is replaced by U; (II) a fragment of the polypeptide of (I) having the activity of an endonuclease. Also, the present invention relates to a vector comprising the nucleic acid molecule and a protein encoded by said nucleic acid molecule. Further, the invention relates to a method of modifying the genome of a eukaryotic cell and a method of producing a non-human vertebrate or mammal.

The invention relates to a method for polar body injection, which comprises removing a polar body from a first egg cell and injecting the polar body into a second egg cell that is in a fertilizable state.

A problem of this invention it to provide a method for differentiate a primordial germ cell into a functional GV stage oocyte by in vitro culture. This invention relates to a method for differentiating a primordial germ cell into a functional GV stage oocyte by in vitro culture, comprising: (a) a step of producing a secondary follicle by culturing the primordial germ cell and supporting cells adjacent to the primordial germ cells under conditions that eliminate the effects of estrogen or a factor having a similar function to estrogen; (b) a step of partially dissociating cells between a granulosa cell layer and a thecal cell layer, wherein an oocyte, the granulosa cell layer, and the thecal cell layer constitute the produced secondary follicle; and (c) a step of differentiating the oocyte into a functional GV stage oocyte by culturing the oocyte, the granulosa cell layer, and the thecal cell layer that constitute the secondary follicle in a medium containing a high-molecular-weight compound.

A frozen egg culturing device includes: a housing portion configured to house a frozen egg contained in a container; a liquid injecting portion; a liquid discharging portion; and an egg outflow preventing portion between the frozen egg contained in the container, and the liquid injecting portion and the liquid discharging portion. A frozen egg culturing method uses the frozen egg culturing device.

The present invention provides a novel oocyte maturation medium or/and embryo culture medium with a chemically defined supplement to produce matured oocytes at high efficiency. The inventive medium or supplement comprises three growth factors, namely, fibroblast growth factor 2 (FGF2), leukemia inhibitory factor (LIF), and insulin-like growth factor 1 (IGF-1) in a synergistic combination. Methods for oocyte and embryo culture are also provided.