MicroRNA-184 downregulates nuclear receptor corepressor 2 in mouse spermatogenesis

<p>Abstract</p> <p>Background</p> <p>There have been increasing attentions on the role of small RNAs, especially microRNAs in post-transcriptional gene regulation during spermatogenesis. MicroRNA-184 (miR-184) has been shown to be mainly expressed in the testis and brain, and that its expression levels are by far the highest in the testis. However, the role of miR-184 in mammalian spermatogenesis remains unclear.</p> <p>Results</p> <p>In this study, we demonstrated that miR-184 levels were increased during mouse postnatal testis development. Specifically, miR-184 expression was restricted to the germ cells from spermatogonia to round spermatids. Overexpression of miR-184 promoted the proliferation of a germ cell line, GC-1spg. Moreover, miR-184 downregulated <it>nuclear receptor corepressor 2 </it>(<it>Ncor2</it>) by targeting its 3' untranslated region through inhibiting NCOR2 protein translation.</p> <p>Conclusions</p> <p>MiR-184 may be involved in the post-transcription regulation of mRNAs such as <it>Ncor2 </it>in mammalian spermatogenesis.</p

UPF2-dependent nonsense-mediated mRNA decay pathway is essential for spermatogenesis by selectively eliminating longer 3'UTR transcripts

During transcription, most eukaryotic genes generate multiple alternative cleavage and polyadenylation (APA) sites, leading to the production of transcript isoforms with variable lengths in the 3' untranslated region (3'UTR). In contrast to somatic cells, male germ cells, especially pachytene spermatocytes and round spermatids, express a distinct reservoir of mRNAs with shorter 3'UTRs that are essential for spermatogenesis and male fertility. However, the mechanisms underlying the enrichment of shorter 3'UTR transcripts in the developing male germ cells remain unknown. Here, we report that UPF2-mediated nonsense-mediated mRNA decay (NMD) plays an essential role in male germ cells by eliminating ubiquitous genes-derived, longer 3'UTR transcripts, and that this role is independent of its canonical role in degrading "premature termination codon" (PTC)-containing transcripts in somatic cell lineages. This report provides physiological evidence supporting a noncanonical role of the NMD pathway in achieving global 3'UTR shortening in the male germ cells during spermatogenesis

Post-Domestication Selection in the Maize Starch Pathway

Modern crops have usually experienced domestication selection and subsequent genetic improvement (post-domestication selection). Chinese waxy maize, which originated from non-glutinous domesticated maize (Zea mays ssp. mays), provides a unique model for investigating the post-domestication selection of maize. In this study, the genetic diversity of six key genes in the starch pathway was investigated in a glutinous population that included 55 Chinese waxy accessions, and a selective bottleneck that resulted in apparent reductions in diversity in Chinese waxy maize was observed. Significant positive selection in waxy (wx) but not amylose extender1 (ae1) was detected in the glutinous population, in complete contrast to the findings in non-glutinous maize, which indicated a shift in the selection target from ae1 to wx during the improvement of Chinese waxy maize. Our results suggest that an agronomic trait can be quickly improved into a target trait with changes in the selection target among genes in a crop pathway

Effects of Different Thawing Methods on the Quality of Micropterus salmoides at Room Temperature

In order to choose a suitable thawing method for Micropterus salmoides (room temperature thawing, running water thawing, saltwater thawing, ultrasonic static water thawing and ultrasonic running water thawing), this paper took Micropterus salmoides as the research subject. To investigate the effects of different thawing methods on water retention, total volatile base nitrogen (TVB-N), malondialdehyde content, peroxide value, total sulfhydryl content and Ca2+-ATPase activity of Micropterus salmoides. At the same time, the changes of texture properties such as hardness, elasticity and adhesion of fish were analyzed. The results showed that the normal temperature thaw 219 min, longest, fish water retention, lipid and protein oxidation was the most serious. Thawing water and salt water thawing time consuming 35 and 55 min, respectively, was the shorter of the normal temperature thaw, but fish water retention, protein oxidation, quality and structure characteristics of the various quality indexes such as the change was still serious. After ultrasonic static water thawing, the fish had better water retention and texture characteristics, and could effectively alleviate the oxidation of fish protein, but the lipid oxidation was more serious. Ultrasonic flow water thawing could complete the thawing of fish within 24 minutes, which was more efficient. Compared with other thawing methods, it could effectively maintain the water retention and texture characteristics of fish, and effectively delay the oxidation of fish protein and lipid. Ultrasonic thawing of frozen water, therefore, Micropterus salmoides had little effect on quality, was the most suitable thawing method

Deficient LRRC8A-dependent volume-regulated anion channel activity is associated with male infertility in mice

Ion channel-controlled cell volume regulation is of fundamental significance to the physiological function of sperm. In addition to volume regulation, LRRC8A-dependent volume-regulated anion channel (VRAC) activity is involved in cell cycle progression, insulin signaling, and cisplatin resistance. Nevertheless, the contribution of LRRC8A and its dependent VRAC activity in the germ cell lineage remain unknown. By utilizing a spontaneous Lrrc8a mouse mutation (c.1325delTG, p.F443*) and genetically engineered mouse models, we demonstrate that LRRC8A-dependent VRAC activity is essential for male germ cell development and fertility. Lrrc8a-null male germ cells undergo progressive degeneration independent of the apoptotic pathway during postnatal testicular development. Lrrc8a-deficient mouse sperm exhibit multiple morphological abnormalities of the flagella (MMAF), a feature commonly observed in the sperm of infertile human patients. Importantly, we identified a human patient with a rare LRRC8A hypomorphic mutation (c.1634G>A, p.Arg545His) possibly linked to Sertoli cell-only syndrome (SCOS), a male sterility disorder characterized by the loss of germ cells. Thus, LRRC8A is a critical factor required for germ cell development and volume regulation in the mouse, and it might serve as a novel diagnostic and therapeutic target for SCOS patients

Diet and lifestyle interventions in postpartum women in China: study design and rationale of a multicenter randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>"Doing the month", or "sitting month", is a traditional practice for postpartum women in China and other Asian countries, which includes some taboos against well-accepted healthy diet and lifestyles in general population. Previous studies have shown this practice may be associated with higher prevalence of postpartum problems. The current multicenter randomized controlled trial (RCT) aims to evaluate outcomes of diet and lifestyle interventions in Chinese postpartum women.</p> <p>Methods/Design</p> <p>The current multicenter RCT will be conducted in three representative areas in China, Shandong province, Hubei province and Guangdong province, which locate in northern, central and southern parts of China, respectively. Women who attend routine pregnancy diagnosis in hospitals or maternal healthcare centers will be invited to take part in this study. At least 800 women who meet our eligibility criteria will be recruited and randomly assigned to the intervention group (n > = 400) and the control group (n > = 400). A three-dimension comprehensive intervention strategy, which incorporates intervention measures simultaneously to individual postpartum woman, their family members and community environment, will be utilized to maximize the effectiveness of intervention. Regular visiting and follow-up will be done in both group; nutrition and health-related measurements will be assessed both before and after the intervention.</p> <p>Discussion</p> <p>To our knowledge, this current study is the first and largest multicenter RCT which focus on the effectiveness of diet and lifestyle intervention on reducing the incidence rate of postpartum diseases and improving health status in postpartum women. We hypothesize that the intervention will reduce the incidence rates of postpartum diseases and improve nutrition and health status due to a balanced diet and reasonable lifestyle in comparison with the control condition. If so, the results of our study will provide especially important evidence for changes in both the concept and action of traditional postpartum practice in China.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov ID NCT01039051.</p