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Molecular and Cellular Endocrinology Jun 2024The endocrine system plays a pivotal role in shaping the mechanisms that ensure successful reproduction. With over a million known insect species, understanding the... (Review)
Review
The endocrine system plays a pivotal role in shaping the mechanisms that ensure successful reproduction. With over a million known insect species, understanding the endocrine control of reproduction has become increasingly complex. Some of the key players include the classic insect lipid hormones juvenile hormone (JH) and ecdysteroids, and neuropeptides such as insulin-like peptides (ILPs). Individual endocrine factors not only modulate their own target tissue but also play crucial roles in crosstalk among themselves, ensuring successful vitellogenesis and oogenesis. Recent advances in omics, gene silencing, and genome editing approaches have accelerated research, offering both fundamental insights and practical applications for studying in-depth endocrine signaling pathways. This review provides an updated and integrated view of endocrine factors modulating vitellogenesis and oogenesis in insect females.
Topics: Animals; Female; Vitellogenesis; Oogenesis; Insecta; Juvenile Hormones; Endocrine System
PubMed: 38494046
DOI: 10.1016/j.mce.2024.112211 -
Reproductive Sciences (Thousand Oaks,... May 2024This paper will review a remarkable new approach to in vitro maturation "IVM" of oocytes from ovarian tissue, based on our results with in vitro oogenesis from somatic... (Review)
Review
This paper will review a remarkable new approach to in vitro maturation "IVM" of oocytes from ovarian tissue, based on our results with in vitro oogenesis from somatic cells. As an aside benefit we also have derived a better understanding of ovarian longevity from ovary transplant. We have found that primordial follicle recruitment is triggered by tissue pressure gradients. Increased pressure holds the follicle in meiotic arrest and prevents recruitment. Therefore recruitment occurs first in the least dense inner tissue of the cortico-medullary junction. Many oocytes can be obtained from human ovarian tissue and mature to metaphase 2 in vitro with no need for ovarian stimulation. Ovarian stimulation may only be necessary for removing the oocyte from the ovary, but this can also be accomplished by simple dissection at the time of ovary tissue cryopreservation. By using surgical dissection of the removed ovary, rather than a needle stick, we can obtain many oocytes from very small follicles not visible with ultrasound. A clearer understanding of ovarian function has come from in vitro oogenesis experiments, and that explains why IVM has now become so simple and robust. Tissue pressure (and just a few "core genes" in the mouse) direct primordial follicle recruitment and development to mature oocyte, and therefore also control ovarian longevity. There are three distinct phases to oocyte development both in vitro and in vivo: in vitro differentiation "IVD" which is not gonadotropin sensitive (the longest phase), in vitro gonadotropin sensitivity "IVG" which is the phase of gonadotropin stimulation to prepare for meiotic competence, and IVM to metaphase II. On any given day 35% of GVs in ovarian tissue have already undergone "IVD" and "IVG" in vivo, and therefore are ready for IVM.
Topics: Female; Animals; Oogenesis; Humans; Ovary; In Vitro Oocyte Maturation Techniques; Oocytes; Ovarian Follicle; Mice
PubMed: 38160209
DOI: 10.1007/s43032-023-01427-1 -
Cells Jan 2024Oogenesis is a developmental process leading to the formation of an oocyte, a haploid gamete, which upon fertilisation and sperm entry allows the male and the female... (Review)
Review
Oogenesis is a developmental process leading to the formation of an oocyte, a haploid gamete, which upon fertilisation and sperm entry allows the male and the female pronuclei to fuse and give rise to a zygote. In addition to forming a haploid gamete, oogenesis builds up a store of proteins, mRNAs, and organelles in the oocyte needed for the development of the future embryo. In several species, such as , the polarity axes determinants of the future embryo must be asymmetrically distributed prior to fertilisation. In the oocyte, the correct positioning of the nucleus is essential for establishing the dorsoventral polarity axis of the future embryo and allowing the meiotic spindles to be positioned in close vicinity to the unique sperm entry point into the oocyte.
Topics: Animals; Male; Female; Drosophila; Semen; Oogenesis; Oocytes; Cell Nucleus
PubMed: 38275826
DOI: 10.3390/cells13020201 -
Nature Communications Jul 2023The hard tick, Ixodes ricinus, a main Lyme disease vector, harbors an intracellular bacterial endosymbiont. Midichloria mitochondrii is maternally inherited and resides...
The hard tick, Ixodes ricinus, a main Lyme disease vector, harbors an intracellular bacterial endosymbiont. Midichloria mitochondrii is maternally inherited and resides in the mitochondria of I. ricinus oocytes, but the consequences of this endosymbiosis are not well understood. Here, we provide 3D images of wild-type and aposymbiotic I. ricinus oocytes generated with focused ion beam-scanning electron microscopy. Quantitative image analyses of endosymbionts and oocyte mitochondria at different maturation stages show that the populations of both mitochondrion-associated bacteria and bacterium-hosting mitochondria increase upon vitellogenisation, and that mitochondria can host multiple bacteria in later stages. Three-dimensional reconstructions show symbiosis-dependent morphologies of mitochondria and demonstrate complete M. mitochondrii inclusion inside a mitochondrion. Cytoplasmic endosymbiont located close to mitochondria are not oriented towards the mitochondria, suggesting that bacterial recolonization is unlikely. We further demonstrate individual globular-shaped mitochondria in the wild type oocytes, while aposymbiotic oocytes only contain a mitochondrial network. In summary, our study suggests that M. mitochondrii modulates mitochondrial fragmentation in oogenesis possibly affecting organelle function and ensuring its presence over generations.
Topics: Imaging, Three-Dimensional; Rickettsiales; Oocytes; Mitochondria; Cytoplasm
PubMed: 37438329
DOI: 10.1038/s41467-023-39758-x -
Development (Cambridge, England) Dec 2023Infertility affects couples worldwide. Premature ovarian insufficiency (POI) refers to loss of ovarian function before 40 years of age and is a contributing factor to...
Infertility affects couples worldwide. Premature ovarian insufficiency (POI) refers to loss of ovarian function before 40 years of age and is a contributing factor to infertility. Several case studies have reported dominant-inherited POI symptoms in families with heterozygous EIF4ENIF1 (4E-T) mutations. However, the effects of EIF4ENIF1 haploinsufficiency have rarely been studied in animal models to reveal the underlying molecular changes related to infertility. Here, we demonstrate that Eif4enif1 haploinsufficiency causes mouse subfertility, impairs oocyte maturation and partially arrests early embryonic development. Using dual-omic sequencing, we observed that Eif4enif1 haploinsufficiency significantly altered both transcriptome and translatome in mouse oocytes, by which we further revealed oocyte mitochondrial hyperfusion and mitochondria-associated ribonucleoprotein domain distribution alteration in Eif4enif1-deficient oocytes. This study provides new insights into the molecular mechanisms underlying clinical fertility failure and new avenues to pursue new therapeutic targets to address infertility.
Topics: Female; Humans; Animals; Mice; Mitochondrial Dynamics; Haploinsufficiency; Oocytes; Infertility; Oogenesis; Primary Ovarian Insufficiency
PubMed: 38088064
DOI: 10.1242/dev.202151 -
Biochemical Genetics Apr 2024RAD51 is a highly conserved recombinase involved in the strand invasion/exchange of double-stranded DNA by homologous single-stranded DNA during homologous recombination... (Review)
Review
RAD51 is a highly conserved recombinase involved in the strand invasion/exchange of double-stranded DNA by homologous single-stranded DNA during homologous recombination repair. Although a majority of existing literature associates RAD51 with the pathogenesis of various types of cancer, recent reports indicate a role of RAD51 in maintenance of fertility. The present study reviews the role of RAD51 and its interacting proteins in spermatogenesis/oogenesis and additionally reports the findings from the molecular genetic screening of RAD51 135 G > C polymorphism in infertile cases and controls. Fifty-nine articles from PubMed and Google Scholar related to the reproductive role of RAD51 were reviewed. For case-control study, the PCR-RFLP method was used to screen the RAD51 135 G > C polymorphism in 201 infertile cases (100 males, 101 females) and 201 age- and gender-matched healthy controls (100 males, 101 females) from Punjab, North-West India. The review of literature shows that RAD51 is indispensable for spermatogenesis and oogenesis in animal models. Reports on the role of RAD51 in human fertility are limited, however it is involved in the pathogenesis of infertility in both males and females. Molecular genetic analyses in the infertile cases and healthy controls showed no statistically significant difference in the genotypic and allelic frequencies for RAD51 135 G > C polymorphism, even after segregation of the cases by type of infertility (primary/secondary). Therefore, the present study concluded that the RAD51 135 G > C polymorphism was neither associated with male nor female infertility in North-West Indians. This is the first report on RAD51 135 G > C polymorphism and infertility.
Topics: Animals; Male; Humans; Female; Genetic Predisposition to Disease; Rad51 Recombinase; Case-Control Studies; Genotype; DNA Repair; Infertility
PubMed: 37563467
DOI: 10.1007/s10528-023-10469-8 -
Clinical Genetics Oct 2023Normal oocyte maturation is an important requirement for the success of human reproduction, and defects in this process will lead to female infertility and repeated...
Normal oocyte maturation is an important requirement for the success of human reproduction, and defects in this process will lead to female infertility and repeated IVF/ICSI failures. In order to identify genetic factors that are responsible for oocyte maturation defect, we used whole exome sequencing in the affected individual with oocyte maturation defect from a consanguineous family and identified a homozygous variant c.853_861del (p.285_287del) in ZFP36L2. ZFP36L2 is a RNA-binding protein, which regulates maternal mRNA decay and oocyte maturation. In vitro studies showed that the variant caused decreased protein levels of ZFP36L2 in oocytes due to mRNA instability and might lead to the loss of its function to degrade maternal mRNAs. Previous study showed that the pathogenic variants in ZFP36L2 were associated with early embryonic arrest. In contrast, we identified a novel ZFP36L2 variant in the affected individual with oocyte maturation defect, which further broadened the mutational and phenotypic spectrum of ZFP36L2, suggesting that ZFP36L2 might be a genetic diagnostic marker for the affected individuals with oocyte maturation defect.
Topics: Female; Humans; Infertility, Female; Oocytes; Oogenesis; Mutation; Homozygote; Transcription Factors
PubMed: 37211617
DOI: 10.1111/cge.14362 -
The EMBO Journal Dec 2023In most metazoans, centrioles are lost during oogenesis, ensuring that the zygote is endowed with the correct number of two centrioles, which are paternally contributed....
In most metazoans, centrioles are lost during oogenesis, ensuring that the zygote is endowed with the correct number of two centrioles, which are paternally contributed. How centriole architecture is dismantled during oogenesis is not understood. Here, we analyze with unprecedent detail the ultrastructural and molecular changes during oogenesis centriole elimination in Caenorhabditis elegans. Centriole elimination begins with loss of the so-called central tube and organelle widening, followed by microtubule disassembly. The resulting cluster of centriolar proteins then disappears gradually, usually moving in a microtubule- and dynein-dependent manner to the plasma membrane. Our analysis indicates that neither Polo-like kinases nor the PCM, which modulate oogenesis centriole elimination in Drosophila, do so in C. elegans. Furthermore, we demonstrate that the central tube protein SAS-1 normally departs initially from the organelle, which loses integrity earlier in sas-1 mutants. Overall, our work provides novel mechanistic insights regarding the fundamental process of oogenesis centriole elimination.
Topics: Animals; Caenorhabditis elegans; Centrioles; Caenorhabditis elegans Proteins; Microtubules; Drosophila; Oogenesis; Cell Cycle Proteins
PubMed: 37987153
DOI: 10.15252/embj.2023115076 -
Journal of Hazardous Materials Aug 2023Homologous recombination (HR) during early oogenesis repairs programmed double-strand breaks (DSBs) to ensure female fertility and offspring health. The exposure of...
Homologous recombination (HR) during early oogenesis repairs programmed double-strand breaks (DSBs) to ensure female fertility and offspring health. The exposure of fetal ovaries to endocrine disrupting chemicals (EDCs) can cause reproductive disorders in the adulthood. The EDC dibutyl phthalate (DBP) is widely distributed in flexible plastic products, leading to ubiquitous human exposure. Here, we report that maternal exposure to DBP caused gross aberrations in meiotic prophase I of fetal oocytes, including delayed progression, impaired DNA damage response, uncoupled localization of DMC1 and RAD51, and decreased HR. However, programmed DSBs were efficiently repaired. DBP exposure negatively regulated lysine crotonylation (Kcr) of MSH6. Similar meiotic defects were observed in fetal ovaries with targeted disruption of Msh6, and mutation of K544cr of MSH6 impaired its association with Ku70, thereby promoting non-homologous end joining (NHEJ) and inhibiting HR. Unlike mature F1 females, F2 female mice exhibited premature follicular activation, precocious puberty, and anxiety-like behaviors. Therefore, DBP can influence early meiotic events, and Kcr of MSH6 may regulate preferential induction of HR or NHEJ for DNA repair during meiosis.
Topics: Humans; Female; Mice; Animals; Adult; Dibutyl Phthalate; Meiosis; Maternal Exposure; DNA-Binding Proteins; Homologous Recombination; DNA Repair; Oocytes
PubMed: 37167869
DOI: 10.1016/j.jhazmat.2023.131540 -
Genes Sep 2023The yak () is a unique breed living on the Qinghai-Tibet Plateau and its surrounding areas, providing locals with a variety of vital means of living and production.... (Review)
Review
The yak () is a unique breed living on the Qinghai-Tibet Plateau and its surrounding areas, providing locals with a variety of vital means of living and production. However, the yak has poor sexual maturity and low fertility. High-quality mature oocytes are the basis of animal breeding technology. Recently, in vitro culturing of oocytes and embryo engineering technology have been applied to yak breeding. However, compared to those observed in vivo, the maturation rate and developmental capacity of in vitro oocytes are still low, which severely limits the application of in vitro fertilization and embryo production in yaks. This review summarizes the endogenous and exogenous factors affecting the in vitro maturation (IVM) and developmental ability of yak oocytes reported in recent years and provides a theoretical basis for obtaining high-quality oocytes for in vitro fertilization and embryo production in yaks.
Topics: Animals; Cattle; Blastocyst; Oocytes; Oogenesis; Fertilization in Vitro; Embryo, Mammalian
PubMed: 37895231
DOI: 10.3390/genes14101882