Micro-vibration results in vitro-derived bovine blastocysts with greater cryotolerance, epigenetic abnormalities, and a massive transcriptional change.

Much effort has been employed to improve the quality of embryos obtained by in vitro production (IVP) given the relevance of this technology to current livestock systems. In this context, dynamic IVP systems have proved beneficial to the embryo once they mimic fluid flows and mechanical forces resulting from the movement of ciliated cells and muscle contraction in the reproductive tract. In the present study, we sought to confirm these initial findings as well as assess potential molecular consequences to the embryo by applying micro-vibration (45 Hz for 5 s once per 60 min) during both oocyte maturation and embryo culture in cattle.

Autophagy deficiency abolishes liver mitochondrial DNA segregation.

Mutations in the mitochondrial genome (mtDNA) are ubiquitous in humans and can lead to a broad spectrum of disorders. However, due to the presence of multiple mtDNA molecules in the cell, co-existence of mutant and wild-type mtDNAs (termed heteroplasmy) can mask disease phenotype unless a threshold of mutant molecules is reached. Importantly, the mutant mtDNA level can change across lifespan as mtDNA segregates in an allele- and cell-specific fashion, potentially leading to disease.

Mitochondrial DNA heteroplasmy is modulated during oocyte development propagating mutation transmission.

Heteroplasmic mitochondrial DNA (mtDNA) mutations are a common cause of inherited disease, but a few recurrent mutations account for the vast majority of new families. The reasons for this are not known. We studied heteroplasmic mice transmitting m.

Evidence of Selection Against Damaged Mitochondria During Early Embryogenesis in the Mouse.

There is evidence of a purifying filter acting in the female germline to prevent the expansion of deleterious mutations in the mitochondrial DNA (mtDNA). Given our poor understanding of this filter, here we investigate the competence of the mouse embryo to eliminate dysfunctional mitochondria. Toward that, mitochondria were damaged by photoirradiation of NZB/BINJ zygotes loaded with chloromethyl-X-rosamine (CMXRos).

Catalytic inhibition of H3K9me2 writers disturbs epigenetic marks during bovine nuclear reprogramming.

Orchestrated events, including extensive changes in epigenetic marks, allow a somatic nucleus to become totipotent after transfer into an oocyte, a process termed nuclear reprogramming. Recently, several strategies have been applied in order to improve reprogramming efficiency, mainly focused on removing repressive epigenetic marks such as histone methylation from the somatic nucleus. Herein we used the specific and non-toxic chemical probe UNC0638 to inhibit the catalytic activity of the histone methyltransferases EHMT1 and EHMT2.

Mitofusin 1 is required for oocyte growth and communication with follicular somatic cells.

Mitochondrial function, largely regulated by the dynamics of this organelle, is inextricably linked to the oocyte health. In comparison with most somatic cells, mitochondria in oocytes are smaller and rounder in appearance, suggesting limited fusion. The functional implications of this distinct morphology, and how changes in the mitochondrial shape translate to mitochondrial function in oogenesis is little understood.

Maternal transmission of mitochondrial diseases.

Given the major role of the mitochondrion in cellular homeostasis, dysfunctions of this organelle may lead to several common diseases in humans. Among these, maternal diseases linked to mitochondrial DNA (mtDNA) mutations are of special interest due to the unclear pattern of mitochondrial inheritance. Multiple copies of mtDNA are present in a cell, each encoding for 37 genes essential for mitochondrial function.

Oocyte mitochondria: role on fertility and disease transmission.

Oocyte mitochondria are increased in number, smaller, and rounder in appearance than mitochondria in somatic cells. Moreover, mitochondrial numbers and activity are narrowly tied with oocyte quality because of the key role of mitochondria to oocyte maturation. During oocyte maturation, mitochondria display great mobility and cluster at specific sites to meet the high energy demand.

Metabolic studies of a patient harbouring a novel S487L mutation in the catalytic subunit of AMPK.

AMP-activated protein kinase (AMPK) regulates many different metabolic pathways in eukaryote cells including mitochondria biogenesis and energy homeostasis. Here we identify a patient with hypotonia, weakness, delayed milestones and neurological impairment since birth harbouring a novel homozygous mutation in the AMPK catalytic α-subunit 1, encoded by the PRKAA1 gene. The homozygous mutation p.

The role of mitochondria in the female germline: Implications to fertility and inheritance of mitochondrial diseases.

Mitochondria play a fundamental role during development of the female germline. They are fragmented, round, and small. Despite these characteristics suggesting that they are inactive, there is accumulating evidence that mitochondrial dysfunctions are a major cause of infertility and generation of aneuploidies in humans.

The Infertility of Repeat-Breeder Cows During Summer Is Associated with Decreased Mitochondrial DNA and Increased Expression of Mitochondrial and Apoptotic Genes in Oocytes.

Oocyte quality is known to be a major cause of infertility in repeat-breeder (RB) and heat-stressed dairy cows. However, the mechanisms by which RB oocytes become less capable of supporting embryo development remain largely unknown. Thus, the aim of this study was to investigate whether the decreased oocyte competence of RB cows (RBs) during summer is associated with an altered gene expression profile and a decrease in mitochondrial DNA (mtDNA) copy number.

Real-Time PCR Quantification of Heteroplasmy in a Mouse Model with Mitochondrial DNA of C57BL/6 and NZB/BINJ Strains.

Mouse models are widely employed to study mitochondrial inheritance, which have implications to several human diseases caused by mutations in the mitochondrial genome (mtDNA). These mouse models take advantage of polymorphisms between the mtDNA of the NZB/BINJ and the mtDNA of common inbred laboratory (i.e.

The adenosine salvage pathway as an alternative to mitochondrial production of ATP in maturing mammalian oocytes.

Although the oocyte is the largest cell in the body and an unavoidable phase in life, its physiology is still poorly understood, and other cell types provide little insight into its unique nature. Even basic cellular functions in the oocyte such as energy metabolism are not yet fully understood. It is known that the mitochondria of the female gamete exhibit an immature form characterized by limited energy production from glucose and oxidative phosphorylation.

Reference gene selection for gene expression analysis of oocytes collected from dairy cattle and buffaloes during winter and summer.

Oocytes from dairy cattle and buffaloes have severely compromised developmental competence during summer. While analysis of gene expression is a powerful technique for understanding the factors affecting developmental hindrance in oocytes, analysis by real-time reverse transcription PCR (RT-PCR) relies on the correct normalization by reference genes showing stable expression. Furthermore, several studies have found that genes commonly used as reference standards do not behave as expected depending on cell type and experimental design.