A novel germ cell-specific protein, SHIP1, forms a complex with chromatin remodeling activity during spermatogenesis.
ABSTRACT To determine the mechanisms of spermatogenesis, it is essential to identify and characterize germ cell-specific genes. Here we describe a protein encoded by a novel germ cell-specific gene, Mm.290718/ZFP541, identified from the mouse spermatocyte UniGene library. The protein contains specific motifs and domains potentially involved in DNA binding and chromatin reorganization. An antibody against Mm.290718/ZFP541 revealed the existence of the protein in testicular spermatogenic cells (159 kDa) but not testicular and mature sperm. Immunostaining analysis of cells at various stages of spermatogenesis consistently showed that the protein is present in spermatocytes and round spermatids only. Transfection assays and immunofluorescence studies indicate that the protein is localized specifically in the nucleus. Proteomic analyses performed to explore the functional characteristics of Mm.290718/ZFP541 showed that the protein forms a unique complex. Other major components of the complex included histone deacetylase 1 (HDAC1) and heat-shock protein A2. Disappearance of Mm.290718/ZFP541 was highly correlated with hyperacetylation in spermatids during spermatogenesis, and specific domains of the protein were involved in the regulation of interactions and nuclear localization of HDAC1. Furthermore, we found that premature hyperacetylation, induced by an HDAC inhibitor, is associated with an alteration in the integrity of Mm.290718/ZFP541 in spermatogenic cells. Our results collectively suggest that the Mm.290718/ZFP541 complex is implicated in chromatin remodeling during spermatogenesis, and we provide further information on the previously unknown molecular mechanism. Consequently, we re-designate Mm.290718/ZFP541 as "SHIP1" representing spermatogenic cell HDAC-interacting protein 1.
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ABSTRACT: Artificial insemination (AI) with cryopreserved boar semen is limited to no more than 1% of the total number of inseminations due to low conception rates and litter sizes. Cryopreservation causes a dramatic decrease in the viability, motility and fertility of spermatozoa, but the underlying mechanism remains unknown. In this study, mRNA expression and protein levels of epigenetic-related genes (Dnmt3a, Dnmt3b, Jhdm2a, Kat8, Prm1, Prm2 and IGF2) in fresh and cryopreserved boar spermatozoa were evaluated using qRT-PCR and ELISA. The results showed that cryopreservation or freezing, which drastically alter the environmental stimuli, can induce epigenetic changes of boar spermatozoa. Dramatic changes of mRNA expression of epigenetic-related genes were observed before and after cryopreservation, and low protein levels of multiple genes were mainly found in program freezing groups with or without LEY. The addition of different cryoprotective agents to the freezing extender can provide better protective effects for boar spermatozoa to avoid freezing or cryopreservation-induced expression changes of epigenetic-related genes.Cryobiology 06/2014; · 1.64 Impact Factor
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ABSTRACT: European pigs that carry Asian haplotypes of a 1.94-Mbp region on pig chromosome 6 have lower levels of androstenone, one of the two main compounds causing boar taint. The objective of our study was to examine potential pleiotropic effects of the Asian low-androstenone haplotypes. A single nucleotide polymorphism marker, rs81308021, distinguishes the Asian from European haplotypes and was used to investigate possible associations of androstenone with production and reproduction traits. Eight traits were available from three European commercial breeds. For the two sow lines studied, a favorable effect on number of teats was detected for the low-androstenone haplotype. In one of these sow lines, a favorable effect on number of spermatozoa per ejaculation was detected for the low-androstenone haplotype. No unfavorable pleiotropic effects were found, which suggests that selection for low-androstenone haplotypes within the 1.94 Mbp would not unfavorably affect the other eight relevant traits.Animal Genetics 09/2014; · 2.21 Impact Factor
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ABSTRACT: Metformin is an oral anti-hyperglycemic drug that acts as an insulin sensitizer in the treatment of diabetes mellitus type 2. It has also been widely used in the treatment of polycystic ovary syndrome (PCOS) and gestational diabetes. This drug has been shown to activate a protein kinase called 5' AMP-activated protein kinase or AMPK. AMPK is present in many tissues making metformin's effect multi factorial. However as metformin crosses the placenta, its use during pregnancy raises concerns regarding potential adverse effects on the mother and fetus. The majority of reports suggest no significant adverse effects or teratogenicity. However, disconcerting reports of male mouse offspring that were exposed to metformin in utero that present with a reduction in testis size, seminiferous tubule size and in Sertoli cell number suggest that we do not understand the full suite of effects of metformin. In addition, recent molecular evidence is suggesting an epigenetic effect of metformin which could explain some of the long-term effects reported. Nevertheless, the data are still insufficient to completely confirm or disprove negative effects of metformin. The aims of this review are to provide a summary of the safety of metformin in various aspects of sexual reproduction, the use of metformin by gestating mothers, and its possible side-effects on offspring from women who are administered metformin during pregnancy. Introduction Metformin is the most widely used drug for reproductive abnormalities associated with insulin resistance and also the oldest insulin sensitizer in the therapeutic management of type 2 diabetes mellitus. Its action reduces hepatic glucose output, increases tissue insulin sensitivity and enhances peripheral glucose uptake, resulting in lower concentrations of glucose without the associated risk of either hypoglycemia or weight gain (1,2). Metformin is a stable hydrophilic biguanide compound that is highly polar, positively charged with a low molecular weight and has pleiotropic actions. It is present in a number of tissues including muscle, liver, pancreas, adipose tissue, hypothalamus, pituitary and the gonads. Despite low lipid solubility, some subcellular studies in rat liver showed that metformin is mainly localized in the cytosol (3) and studies in mice show that metformin may accumulate in certain tissues at higher concentrations than in plasma (4). The passive diffusion of metformin into cells is limited (5), the main transport is the organic cation transporter 1-3 or multidrug and toxic compound extrusion type transporters (MATE1, MATE2) which are able to internalize metformin as described in gut, hepatocytes, renal tubular epithelial cells and reproductive tissues (6). One of the direct effects of metformin identified is to inhibit the activity of the respiratory electron transport chain in mitochondria (7) and to activate the cytoplasmic protein kinase known as AMP-activated protein kinase (AMPK) (8). AMPK is an important sensor of cellular energy homeostasis and is sensitive to the AMP:ATP ratio (9,10). We can note that severalAnnals of Translational Medicine. 05/2014;