Increased expression of miR-325-3p by urocortin 2 and its involvement in stress-induced suppression of LH secretion in rat pituitary

Urocortin 2 (Ucn2) is a member of the corticotropin releasing factor (CRF) peptide family, which binds to CRF type 2 receptor. We previously reported on expression of Ucn2 in proopiomelanocortin cells of rat pituitary and its inhibitory action on LH secretion. We also demonstrated that Ucn2 is involved in the mechanism underlying immobilization-induced suppression of LH secretion; the details remain unclear. Here, we found that Ucn2 increased the expression of miR-325-3p, one of three microRNAs with predicted sequence for binding to LH β-subunit 3'-untranslated region (3'-UTR) in monolayer cultured rat anterior pituitary cells, and that miR-325-3p was expressed in LH cells of the anterior pituitary. Immobilization also increased miR-325-3p expression in the anterior pituitary, and its increase was blocked by pretreatment with anti-Ucn2 IgG. Overexpression of miR-325-3p in cultured pituitary cells significantly suppressed intracellular contents and secretion of LH, while miR-325-3p knockdown blocked Ucn2-induced suppression of intracellular contents and secretion of LH. Coexpression of miR-325-3p with LH β-subunit 3'-UTR-fused luciferase vector significantly suppressed luciferase activity compared with that of mock transfectants. These results suggest that miR-325-3p is involved in immobilization-induced suppression of LH translation and secretion and that Ucn2 plays a role in the increase in miR-325-3p expression.     

Roles of GIG1 and UVI4 in genome duplication in Arabidopsis thaliana

Endomitosis and endoreplication are atypical modes of cell cycle that results in genome duplication in single nucleus. Because the cell size of given cell type is generally proportional to the nuclear DNA content, endoreplication and endomitosis are effective strategy of cell growth, which are widespread in multicellular organisms, especially those in plant kingdom. We found that these processes might be differently regulated by GIGAS CELL1 (GIG1) and its paralog UV-INSENSITIVE4 (UVI4) in Arabidopsis thaliana. GIG1 and UVI4 may negatively regulate activities of anaphase-promoting complex or cyclosome (APC/C) ubiquitin ligase that acts as an important mitotic regulator. The gig1 mutation induced ectopic occurrence of endomitosis during somatic cell division, while it has been reported that uvi4 mutation resulted in premature occurrence of endoreplication during organ development. Overexpression of GIG1 and UVI4 dramatically increased the amount of mitotic cyclin, CYCB1;1, a well-known substrate of APC/C. Ectopic endomitosis in gig1 was enhanced by mutation in CYCB2;2 and suppressed by downregulation of APC10 encoding a core subunit of APC/C. Overexpression of CDC20.1, an activator protein of APC/C, further promoted the ectopic endomitosis in gig1. These findings suggest that endomitosis and endoreplication are regulated by similar molecular mechanisms, in which two related proteins, GIG1 and UVI4, may inhibit APC/C in different ways.     

Passage of a Sendai Virus Recombinant in Embryonated Chicken Eggs Leads to Markedly Rapid Accumulation of U-to-C Transitions in a Limited Region of the Viral Genome

The P gene of paramyxoviruses is unique in producing not only P but also “accessory” C and/or V proteins. Successful generation of C- or V-deficient recombinant viruses using a reverse genetics technique has been revealing their importance in viral pathogenesis as well as replication. As for Sendai virus (SeV), the C proteins, a nested set of four polypeptides C’, C, Y1, and Y2, have been shown to exert multiple functions in escaping from the host innate immunity, inhibiting virus-induced apoptosis, promoting virus assembly and budding, and regulating viral RNA synthesis. In this study, we subjected the 4C(-) recombinant lacking expression of all four C proteins to serial passages through eggs, and found the rapid emergence of a C-recovered revertant virus. Unlike the SeV strains or the recombinants reported previously or tested in this study, this was caused by an exceptionally quick accumulation of U-to-C transitions in a limited region of the 4C(-) genome causing recovery of the C protein expression. These results suggest that a lack of C proteins could lead unexpectedly to strong selective pressures, and that the C proteins might play more critical roles in SeV replication than ever reported.     

AP2σ Mutations Impair Calcium-Sensing Receptor Trafficking and Signaling,and Show an Endosomal Pathway to Spatially Direct G-Protein Selectivity

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Synthetic studies on glycosphingolipids from Protostomia phyla: total syntheses of glycosphingolipids from the parasite, Echinococcus multilocularis

Efficient and systematic syntheses of four neutral glycosphingolipids that have been isolated from the metacestodes of Echinococcus multilocularis have been achieved. A key step is the direct glycosylation of galactosyl donors using thioglycosides with benzoyl ceramide in the presence of N-iodosuccinimide (NIS)/TfOH, which gave the desired oligosaccharide derivatives. The fully protected glycosides 13, 20, 22 and 25 were deprotected to give four target glycosphingolipids (1-4).     

Homeostatic Epithelial Renewal in the Gut Is Required for Dampening a Fatal Systemic Wound Response in Drosophila

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Highlights? Caspase activity is required for gut cell turnover ? Caspase is specifically activated in ECs of midgut after wounding ? Caspase activity in ECs is required for fly survival after wounding ? EC turnover is required for dampening the production of lethal factors after wounding     

Physiological responses of simulated karate sparring matches in young men and boys

The purpose of this study was to investigate the duration of each series of offensive and defensive techniques and the cardiovascular, metabolic, and perceptual responses during 2- and 3-minute bouts of simulated karate sparring. Six young men (age, 18-20 years) and 6 boys (age, 16-17 years) participated in this study. We formed 3 pairs of men and 3 pairs of boys to create a demanding competitive environment. After a rest period, each pair performed a 2-minute bout of sparring, sat quietly for 60 minutes, and then performed 3-minute bout of sparring. We measured oxygen uptake (Vo2), heart rate (HR), and blood lactate responses and ascertained the rate of perceived exertion (RPE) and energy expenditure (EE) during these sparring bouts. The ventilatory threshold was estimated from ventilatory equivalent and Vo2 obtained during the treadmill test. The duration of each series of offensive and defensive techniques was videotaped. During the 2- and 3-minute bouts of sparring, the duration of longest series of offensive and/or defensive combination techniques performed were 2.1 +/- 1.0 and 1.8 +/- 0.4 seconds, respectively; the mean total times of performing offensive and defensive techniques were 13.3 +/- 3.3 and 19.4 +/- 5.5 seconds, respectively. The mean oxygen uptake (Vo2), the percentage of maximum oxygen uptake (%Vo2max), HR, percentage of maximum HR, RPE, and EE for a 3-minute bout of sparring were significantly higher than for a 2-minute bout of sparring. The mean %Vo2max values for these bouts of sparring were below the ventilatory threshold. It is recommended that karate practitioners perform more specific weight training, plyometric exercises, and interval training to increase the ability to buffer acid muscle and blood concentrations and to build lean body mass, strength, and power to develop the specific motor skills required in sparring.     

Two pathways for lysophosphatidic acid production

Lysophosphatidic acid (LPA, 1- or 2-acyl-sn-glycerol 3-phosphate) is a simple phospholipid but displays an intriguing cell biology that is mediated via interactions with G protein-coupled seven transmembrane receptors (GPCRs). So far, five GPCRs, designated LPA(1-5), and, more recently, two additional GPCRs, GPR87 and P2Y5, have been identified as receptors for LPA. These LPA receptors can be classified into two families, the EDG and P2Y families, depending on their primary structures. Recent studies on gene targeting mice and family diseases of these receptors revealed that LPA is involved in both pathological and physiological states including brain development (LPA(1)), neuropathy pain (LPA(1)), lung fibrosis (LPA(1)), renal fibrosis (LPA(1)) protection against radiation-induced intestinal injury (LPA(2)), implantation (LPA(3)) and hair growth (P2Y5). LPA is produced both in cells and biological fluids, where multiple synthetic reactions occur. There are at least two pathways for LPA production. In serum or plasma, LPA is predominantly produced by a plasma enzyme called autotaxin (ATX). ATX is a multifunctional ectoenzyme and is involved in many patho-physiological conditions such as cancer, neuropathy pain, lymphocyte tracking in lymph nodes, obesity, diabetes and embryonic blood vessel formation. LPA is also produced from phosphatidic acid (PA) by its deacylation catalyzed by phospholipase A (PLA)-type enzymes. However, the physiological roles of this pathway as well as the enzymes involved remained to be solved. A number of phospholipase A(1) and A(2) isozymes could be involved in this pathway. One PA-selective PLA(1) called mPA-PLA(1)alpha/LIPH is specifically expressed in hair follicles, where it has a critical role in hair growth by producing LPA through a novel LPA receptor called P2Y5.