Effect of endometrial biopsy method on ribonucleic acid quality and gene expression analysis in patients with leiomyoma.

Objective: To compare ribonucleic acid (RNA) quantity and purity in tissue collected with different endometrial sampling methods to establish the optimal tool for use in endometrial gene expression studies.

Design: Observational study.

Setting: University hospital.

Single-cell mA mapping in vivo using picoMeRIP-seq.

Current N-methyladenosine (mA) mapping methods need large amounts of RNA or are limited to cultured cells. Through optimized sample recovery and signal-to-noise ratio, we developed picogram-scale mA RNA immunoprecipitation and sequencing (picoMeRIP-seq) for studying mA in vivo in single cells and scarce cell types using standard laboratory equipment. We benchmark mA mapping on titrations of poly(A) RNA and embryonic stem cells and in single zebrafish zygotes, mouse oocytes and embryos.

The RNA mA landscape of mouse oocytes and preimplantation embryos.

Despite the significance of N-methyladenosine (mA) in gene regulation, the requirement for large amounts of RNA has hindered mA profiling in mammalian early embryos. Here we apply low-input methyl RNA immunoprecipitation and sequencing to map mA in mouse oocytes and preimplantation embryos. We define the landscape of mA during the maternal-to-zygotic transition, including stage-specifically expressed transcription factors essential for cell fate determination.

Spatial and temporal changes in follicle distribution in the human ovarian cortex.

Research Question: How does follicle distribution evolve in the human ovarian cortex between the ages of 20 and 35 years?

Design: Fragments of ovarian cortex from women undergoing unilateral oophorectomy for fertility preservation were obtained for quantitative histological assessment, including recording the two-dimensional coordinates of the follicles. Data were analysed using spatial statistical methods.

Results: A total of 53 ovarian cortex tissue samples, containing 1-803 follicles each, were obtained from 14 women aged 20-35 years.

Reversible RNA modifications in meiosis and pluripotency.

Post-transcriptional RNA modifications were discovered several decades ago, but the reversible nature of RNA modifications has only recently been discovered. Owing to technological advances, knowledge of epitranscriptomic marks and their writers, readers and erasers has recently advanced tremendously. Here we focus on the roles of the dynamic methylation and demethylation of internal adenosines in mRNA in germ cells and pluripotent stem cells.

Broad histone H3K4me3 domains in mouse oocytes modulate maternal-to-zygotic transition.

Maternal-to-zygotic transition (MZT) is essential for the formation of a new individual, but is still poorly understood despite recent progress in analysis of gene expression and DNA methylation in early embryogenesis. Dynamic histone modifications may have important roles in MZT, but direct measurements of chromatin states have been hindered by technical difficulties in profiling histone modifications from small quantities of cells. Recent improvements allow for 500 cell-equivalents of chromatin per reaction, but require 10,000 cells for initial steps or require a highly specialized microfluidics device that is not readily available.

Autotransplantation of cryopreserved ovarian tissue after treatment for malignant disease - the first Norwegian results.

Introduction: With increasing survival rates after treatment for cancer in prepubertal girls and women of reproductive age, an increasing focus on quality of life has emerged. Both irradiation and cytotoxic drugs can be detrimental to future fertility, consequently several treatment alternatives have been developed to spare or restore fertility in young females diagnosed with cancer. One of these options is cryopreservation of ovarian tissue before treatment and autotransplantation at a later time.

Female reproductive decline is determined by remaining ovarian reserve and age.

The early decline and loss of female fertility in humans and other species represents an evolutionary paradox. Despite being born with a vast stock of oocytes, females encounter an exhaustion of ovarian reserve and sterility half way through their natural lives. Female reproductive ageing has been proposed to proceed as an ongoing decline in ovarian reserve, determined by remaining ovarian follicle number.

ALKBH4 depletion in mice leads to spermatogenic defects.

ALKBH4, an AlkB homologue in the 2-oxoglutarate and Fe2+ dependent hydroxylase family, has previously been shown to regulate the level of monomethylated lysine-84 in actin and thereby indirectly influences the ability of non-muscular myosin II to bind actin filaments. ALKBH4 modulates fundamental processes including cytokinesis and cell motility, and its depletion is lethal during early preimplantation embryo stage. The aim of this study was to investigate the effect of ALKBH4 deficiency in a physiological context, using inducible Alkbh4 knockout mice.

Therapeutic potential of somatic cell nuclear transfer for degenerative disease caused by mitochondrial DNA mutations.

Induced pluripotent stem cells (iPSCs) hold much promise in the quest for personalised cell therapies. However, the persistence of founder cell mitochondrial DNA (mtDNA) mutations limits the potential of iPSCs in the development of treatments for mtDNA disease. This problem may be overcome by using oocytes containing healthy mtDNA, to induce somatic cell nuclear reprogramming.

Mitochondrial DNA disease: new options for prevention.

Very recently, two papers have presented intriguing data suggesting that prevention of transmission of human mitochondrial DNA (mtDNA) disease is possible. [Craven, L., Tuppen, H.

Pronuclear transfer in human embryos to prevent transmission of mitochondrial DNA disease.

Mutations in mitochondrial DNA (mtDNA) are a common cause of genetic disease. Pathogenic mutations in mtDNA are detected in approximately 1 in 250 live births and at least 1 in 10,000 adults in the UK are affected by mtDNA disease. Treatment options for patients with mtDNA disease are extremely limited and are predominantly supportive in nature.