Obesity and PCOS: the effect of metabolic derangements on endometrial receptivity at the time of implantation.

Successful embryonic implantation is the result of a receptive endometrium, a functional embryo at the blastocyst stage and a synchronized dialog between maternal and embryonic tissues. Successful implantation requires the endometrium to undergo steroid-dependent change during each menstrual cycle, exhibiting a short period of embryonic receptivity known as the window of implantation. The term "endometrial receptivity" was introduced to define the state of the endometrium during the window of implantation.

The fatty acid beta-oxidation pathway is important for decidualization of endometrial stromal cells in both humans and mice.

Embryo implantation and development requires the endometrial stromal cells (ESCs) to undergo decidualization. This differentiation process requires glucose utilization, and blockade of the pentose phosphate pathway inhibits decidualization of ESCs both in vitro and in vivo. Glucose and fatty acids are energy substrates for many cell types, and fatty acid beta-oxidation is critical for embryo implantation.

Glucosamine inhibits decidualization of human endometrial stromal cells and decreases litter sizes in mice.

Embryo implantation in the uterus depends on decidualization of the endometrial stromal cells (ESCs), and glucose utilization via the pentose phosphate pathway is critical in this process. We hypothesized that the amino sugar glucosamine may block the pentose phosphate pathway via inhibition of the rate-limiting enzyme glucose-6-phosphate dehydrogenase in ESCs and therefore impair decidualization and embryo implantation, thus preventing pregnancy. Both human primary and immortalized ESCs were decidualized in vitro in the presence of 0, 2.

Meiosis in male Drosophila.

Meiosis entails sorting and separating both homologous and sister chromatids. The mechanisms for connecting sister chromatids and homologs during meiosis are highly conserved and include specialized forms of the cohesin complex and a tightly regulated homolog synapsis/recombination pathway designed to yield regular crossovers between homologous chromatids. Drosophila male meiosis is of special interest because it dispenses with large segments of the standard meiotic script, particularly recombination, synapsis and the associated structures.

Essential role of β-human 8-oxoguanine DNA glycosylase 1 in mitochondrial oxidative DNA repair.

8-Oxoguanine (8-OG) is the major mutagenic base lesion in DNA caused by reactive oxygen species (ROS) and accumulates in both nuclear and mitochondrial DNA (mtDNA). In humans, 8-OG is primarily removed by human 8-OG DNA glycosylase 1 (hOGG1) through the base excision repair (BER) pathway. There are two major hOGG1 isoforms, designated α- and β-hOGG1, generated by alternative splicing, and they have distinct subcellular localization: cell nuclei and mitochondria, respectively.

Homologous pairing and the role of pairing centers in meiosis.

Homologous pairing establishes the foundation for accurate reductional segregation during meiosis I in sexual organisms. This Commentary summarizes recent progress in our understanding of homologous pairing in meiosis, and will focus on the characteristics and mechanisms of specialized chromosome sites, called pairing centers (PCs), in Caenorhabditis elegans and Drosophila melanogaster. In C.

Homolog pairing and sister chromatid cohesion in heterochromatin in Drosophila male meiosis I.

Drosophila males undergo meiosis without recombination or chiasmata but homologous chromosomes pair and disjoin regularly. The X-Y pair utilizes a specific repeated sequence within the heterochromatic ribosomal DNA blocks as a pairing site. No pairing sites have yet been identified for the autosomes.

SOLO: a meiotic protein required for centromere cohesion, coorientation, and SMC1 localization in Drosophila melanogaster.

Sister chromatid cohesion is essential to maintain stable connections between homologues and sister chromatids during meiosis and to establish correct centromere orientation patterns on the meiosis I and II spindles. However, the meiotic cohesion apparatus in Drosophila melanogaster remains largely uncharacterized. We describe a novel protein, sisters on the loose (SOLO), which is essential for meiotic cohesion in Drosophila.

Reduced expression of von Hippel-Lindau gene in subjects exposed to polychlorinated biphenyls and dibenzofurans.

Polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) are ubiquitous pollutants found in the environment and human tissues. A cohort in Taiwan has undergone follow-up for 24 years after exposure to high levels of PCBs and PCDFs. The incidence of chloracne, hyperkeratosis, and abnormal nail was increased among exposed people.

Streptococcal pyrogenic exotoxin B cleaves human S-adenosylhomocysteine hydrolase and induces hypermethioninemia.

Group A Streptococcus is a common pathogen that causes pharyngitis, impetigo, myositis, and lethal streptococcal toxic shock syndrome. Streptococcal pyrogenic exotoxin B (SPE B) is strongly associated with the severity of disease. SPE B is a cysteine protease and matures itself by autocatalysis.

Hepatitis B virus pre-S2 mutant surface antigen induces degradation of cyclin-dependent kinase inhibitor p27Kip1 through c-Jun activation domain-binding protein 1.

The hepatitis B virus (HBV) large surface antigen (LHBS) mutant with deletion at the pre-S(2) region accumulates in endoplasmic reticulum (ER) and is associated with HBV-induced hepatocellular carcinogenesis. In this study, we found that the pre-S(2) LHBS mutant directly interacts with the Jun activation domain-binding protein 1 (JAB1). Association of pre-S(2) LHBS with JAB1 dissociated JAB1 from the JAB1/IRE1 complex in ER.

HHR23A, a human homolog of Saccharomyces cerevisiae Rad23, regulates xeroderma pigmentosum C protein and is required for nucleotide excision repair.

HHR23A and hHR23B are the human homologs of Saccharomyces cerevisiae Rad23. hHR23B is associated with the nucleotide excision repair (NER) factor xeroderma pigmentosum C (XPC) protein and is required for global genome repair. The function of hHR23A is not yet clear.

Two UVC-induced stress response pathways in HeLa cells identified by cDNA microarray.

Environmental toxins induce multiple effects in vivo, involving various molecular pathways. The ultraviolet C (UVC, 254 nm) component of sunlight can cause strong cytotoxic and genotoxic effects. In this study, UVC-induced stress response factors were analyzed by cDNA microarray, using the Millennium(R) Nylon membrane chip system.