The cumulus oophorus (discus proligerus) is a cluster of cells that surround the

oocyte An oocyte (, oöcyte, or ovocyte) is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female ger ...

both in the

ovarian follicle An ovarian follicle is a roughly spheroid cellular aggregation set found in the ovaries. It secretes hormones that influence stages of the menstrual cycle. In humans, women have approximately 200,000 to 300,000 follicles at the time of puberty, ea ...

and after

ovulation Ovulation is an important part of the menstrual cycle in female vertebrates where the egg cells are released from the ovaries as part of the ovarian cycle. In female humans ovulation typically occurs near the midpoint in the menstrual cycle and ...

. In the antral follicle, it may be regarded as an extension of the

membrana granulosa The larger ovarian follicles consist of an external fibrovascular coat, connected with the surrounding stroma of the ovary by a network of blood vessels, and an internal coat, which consists of several layers of nucleated cells, called the membr ...

. The innermost layer of these cells is the

corona radiata In neuroanatomy, the corona radiata is a white matter sheet that continues inferiorly as the internal capsule and superiorly as the centrum semiovale. This sheet of both ascending and descending axons carries most of the neural traffic from and ...

. This layer of cells must be penetrated by

spermatozoa A spermatozoon (; also spelled spermatozoön; : spermatozoa; ) is a motile sperm cell (biology), cell produced by male animals relying on internal fertilization. A spermatozoon is a moving form of the ploidy, haploid cell (biology), cell that is ...

for

fertilization Fertilisation or fertilization (see American and British English spelling differences#-ise, -ize (-isation, -ization), spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give ...

to occur.

Functions

Functions of the cumulus oophorus include coordination of follicular development and oocyte maturation. Mechanisms of the latter include stimulation of amino acid transport and

sterol A sterol is any organic compound with a Skeletal formula, skeleton closely related to Cholestanol, cholestan-3-ol. The simplest sterol is gonan-3-ol, which has a formula of , and is derived from that of gonane by replacement of a hydrogen atom on ...

biosynthesis Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme-Catalysis, catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthe ...

and regulation of oocyte

gene transcription Transcription is the process of copying a segment of DNA into RNA for the purpose of gene expression. Some segments of DNA are transcribed into RNA molecules that can encode proteins, called messenger RNA (mRNA). Other segments of DNA are transc ...

. It also provides energy substrates for oocyte meiotic resumption and promotes glycolysis. Cumulus oophorus cells contribute heavily to the maturation and eventual fertilization of an oocyte. As a follicle grows in size and the antrum develops, more layers of cumulus oophorus cells accumulate around the oocyte to aid in the acrosome reaction and sperm penetration into the oocyte. The proximity between the cumulus oophorus cells and the oocyte favors bidirectional communication, which is vital for oocyte development.

Gene expression profiling

As a part of the process of

in vitro fertilization In vitro fertilisation (IVF) is a process of fertilisation in which an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating the ovulatory process, then removing an ovum or ova (egg or eggs) from ...

gene expression profiling In the field of molecular biology, gene expression profiling is the measurement of the activity (the gene expression, expression) of thousands of genes at once, to create a global picture of cellular function. These profiles can, for example, dis ...

of cumulus cells can be performed to estimate oocyte quality and the efficiency of an ovarian hyperstimulation protocol, and may indirectly predict oocyte

aneuploidy Aneuploidy is the presence of an abnormal number of chromosomes in a cell (biology), cell, for example a human somatic (biology), somatic cell having 45 or 47 chromosomes instead of the usual 46. It does not include a difference of one or more plo ...

, embryo development and pregnancy outcomes. Increased knowledge in these aspects is useful in, for example,

embryo selection In vitro fertilisation (IVF) is a process of fertilisation in which an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating the ovulatory process, then removing an ovum or ova (egg or eggs) from t ...

. In gene

expression profiling In the field of molecular biology, gene expression profiling is the measurement of the activity (the expression) of thousands of genes at once, to create a global picture of cellular function. These profiles can, for example, distinguish between ...

of cumulus cells, genes where increased expression is correlated with higher oocyte competence or better pregnancy outcomes, include: HAS2, GREM1 and

PTGS2 Cyclooxygenase-2 (COX-2), also known as prostaglandin-endoperoxide synthase 2 ( HUGO PTGS2), is an enzyme that in humans is encoded by the ''PTGS2'' gene. In humans it is one of three cyclooxygenases. It is involved in the conversion of arachid ...

. In contrast, genes where increased expression is correlated with lower oocyte competence or worse pregnancy outcomes include:

BDNF Brain-derived neurotrophic factor (BDNF), or abrineurin, is a protein found in the and the periphery. that, in humans, is encoded by the ''BDNF'' gene. BDNF is a member of the neurotrophin family of growth factors, which are related to the cano ...

, CCND2,

CXCR4 C-X-C chemokine receptor type 4 (CXCR-4) also known as fusin or CD184 (cluster of differentiation 184) is a protein that in humans is encoded by the ''CXCR4'' gene. The protein is a CXC chemokine receptor. Function CXCR-4 is an alpha- chemo ...

, GPX3, HSPB1,

DVL3 Segment polarity protein dishevelled homolog DVL-3 is a protein that in humans is encoded by the ''DVL3'' gene. This gene is a member of a multi-gene family which shares strong similarity with the Drosophila dishevelled gene, dsh. The Drosophila ...

, DHCR7,

CTNND1 p120 catenin, or simply p120, also called catenin delta-1, is a protein that in humans is encoded by the ''CTNND1'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a se ...

, TRIM28,

STAR A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

, AREG, CX43,

, SCD1 and SCD5.

References

External links

* - "Mammal, bovine ovary (LM, Medium)" * * * - "Female Reproductive System: ovary, cumulus oophorus" {{DEFAULTSORT:Cumulus Oophorus Mammal female reproductive system