IN BRIEF: Understanding the establishment of post-fertilization totipotency has broad implications for modern biotechnologies. This review summarizes the current knowledge of putative egg components governing this process following natural fertilization and after somatic cell nuclear transfer. ABSTRACT: The mammalian oocyte is a unique cell, and comprehending its physiology and biology is essential for understanding fertilization, totipotency and early events of embryogenesis. Consequently, research in these areas influences the outcomes of various technologies, for example, the production and conservation of laboratory and large animals with rare and valuable genotypes, the rescue of the species near extinction, as well as success in human assisted reproduction. Nevertheless, even the most advanced and sophisticated reproductive technologies of today do not always guarantee a favorable outcome. Elucidating the interactions of oocyte components with its natural partner cell - the sperm or an 'unnatural' somatic nucleus, when the somatic cell nucleus transfer is used is essential for understanding how totipotency is established and thus defining the requirements for normal development. One of the crucial aspects is the stoichiometry of different reprogramming and remodeling factors present in the oocyte and their balance. Here, we discuss how these factors, in combination, may lead to the formation of a new organism. We focus on the laboratory mouse and its genetic models, as this species has been instrumental in shaping our understanding of early post-fertilization events.
- MeSH
- buněčné jádro * fyziologie MeSH
- embryonální vývoj MeSH
- lidé MeSH
- myši MeSH
- oocyty fyziologie MeSH
- savci MeSH
- sperma * MeSH
- spermie fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
It is now approximately 25 years since the sheep Dolly, the first cloned mammal where the somatic cell nucleus from an adult donor was used for transfer, was born. So far, somatic cell nucleus transfer, where G1-phase nuclei are transferred into cytoplasts obtained by enucleation of mature metaphase II (MII) oocytes followed by the activation of the reconstructed cells, is the most efficient approach to reprogram/remodel the differentiated nucleus. In general, in an enucleated oocyte (cytoplast), the nuclear envelope (NE, membrane) of an injected somatic cell nucleus breaks down and chromosomes condense. This condensation phase is followed, after subsequent activation, by chromatin decondensation and formation of a pseudo-pronucleus (i) whose morphology should resemble the natural postfertilization pronuclei (PNs). Thus, the volume of the transferred nuclei increases considerably by incorporating the content released from the germinal vesicles (GVs). In parallel, the transferred nucleus genes must be reset and function similarly as the relevant genes in normal embryo reprogramming. This, among others, covers the relevant epigenetic modifications and the appropriate organization of chromatin in pseudo-pronuclei. While reprogramming in SCNT is often discussed, the remodeling of transferred nuclei is much less studied, particularly in the context of the developmental potential of SCNT embryos. It is now evident that correct reprogramming mirrors appropriate remodeling. At the same time, it is widely accepted that the process of rebuilding the nucleus following SCNT is instrumental to the overall success of this procedure. Thus, in our contribution, we will mostly focus on the remodeling of transferred nuclei. In particular, we discuss the oocyte organelles that are essential for the development of SCNT embryos.
- MeSH
- buněčné jádro metabolismus MeSH
- chromatin metabolismus MeSH
- oocyty MeSH
- ovce genetika MeSH
- savci genetika MeSH
- techniky jaderného přenosu * veterinární MeSH
- zvířata MeSH
- zygota * metabolismus MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The northern white rhinoceros (NWR, Ceratotherium simum cottoni) is the most endangered mammal in the world with only two females surviving. Here we adapt existing assisted reproduction techniques (ART) to fertilize Southern White Rhinoceros (SWR) oocytes with NWR spermatozoa. We show that rhinoceros oocytes can be repeatedly recovered from live SWR females by transrectal ovum pick-up, matured, fertilized by intracytoplasmic sperm injection and developed to the blastocyst stage in vitro. Next, we generate hybrid rhinoceros embryos in vitro using gametes of NWR and SWR. We also establish embryonic stem cell lines from the SWR blastocysts. Blastocysts are cryopreserved for later embryo transfer. Our results indicate that ART could be a viable strategy to rescue genes from the iconic, almost extinct, northern white rhinoceros and may also have broader impact if applied with similar success to other endangered large mammalian species.
- MeSH
- asistovaná reprodukce veterinární MeSH
- buněčná diferenciace MeSH
- buněčné linie MeSH
- embryo savčí * MeSH
- embryonální kmenové buňky cytologie MeSH
- ohrožené druhy * MeSH
- Perissodactyla * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Morbilliviruses, such as Cetacean morbillivirus (CeMV) or Phocine distemper virus (PDV), represent a growing threat for marine mammals on both hemispheres. Because free-ranging animal populations strongly rely on natural resistance mechanisms, innate immunity-related genes and virus cell entry receptor genes may represent key factors involved in susceptibility to CeMV in Cetaceans. Using the next generation sequencing technology, we have sequenced 11 candidate genes in two model species, Stenella coeruleoalba and Phocoena phocoena. Suitable single nucleotide polymorphism markers of potential functional importance, located in genes coding for basigin (BSG, CD147), the signaling lymphocyte activating molecule (SLAMF1), the poliovirus-related receptor-4 (NECTIN4, PVRL4), toll-like receptors 3, 7, 8 (TLR3, TLR7, TLR8), natural resistance-associated macrophage protein (SLC11A1) and natural cytotoxicity triggering receptor 1 (NCR1), were identified in each model species, along with MHC-DQB haplotypes unique for each species. This set of molecular markers represents a potentially useful tool for studying host genetic variation and susceptibility to morbillivirus infection in Cetaceans as well as for studying functionally important genetic diversity of selected Cetacean populations.
- MeSH
- basigin genetika imunologie MeSH
- biologické markery metabolismus MeSH
- delfíni rodu Stenella genetika imunologie virologie MeSH
- exprese genu MeSH
- genetická predispozice k nemoci * MeSH
- histokompatibilita - antigeny třídy II genetika imunologie MeSH
- infekce viry z rodu Morbillivirus genetika imunologie virologie MeSH
- jednonukleotidový polymorfismus * MeSH
- molekuly buněčné adheze genetika imunologie MeSH
- Morbillivirus imunologie patogenita MeSH
- Phocoena genetika imunologie virologie MeSH
- proteiny přenášející kationty genetika imunologie MeSH
- receptor 1 spouštějící přirozenou cytotoxicitu genetika imunologie MeSH
- SLAMF1 protein genetika imunologie MeSH
- toll-like receptor 3 genetika imunologie MeSH
- toll-like receptor 7 genetika imunologie MeSH
- toll-like receptor 8 genetika imunologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
A prospective study to create radiographic classification of caudal vertebral anomalies in dogs was performed and the prevalence of the disorders estimated. Radiographic examination of the caudal vertebrae was performed in 595 client-owned dogs undergoing routine radiological examination of the hip joints. Anomalies of the caudal vertebrae were divided into four groups: (1) congenital anomalies with aberrant fusion of the vertebral epiphysis, like hemivertebra, block or transitional vertebra; (2) morphological anomalies like vertebra curva and dysplastic vertebral epiphysis; (3) post-traumatic changes, represented by fracture or luxation; and (4) degenerative changes, represented by spondylosis, osteophyte formation and mineralisation of intervertebral spaces. A total of 303 caudal vertebral anomalies were detected in 259 dogs (43.53% of all dogs examined). A single type of vertebral anomaly was present in 215 dogs and a combination of two pathologies was recorded in 44 dogs, which represents 83.01% and 16.99%, respectively, of the affected dogs. Congenital anomaly was present in 11.09% of the dogs examined. Sacrocaudal transitional vertebra was the most common congenital anomaly, present in 12.74% of the affected dogs. Radiographic examination of the caudal vertebrae is recommended as an essential part of any screening process to confirm the presence of congenital anomaly as a cause of kinked tail.
