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81.
Summary The differentiation capacity of the rat epididymis after depletion of androgen was studied in organ culture and in castrated rats. The differentiation of narrow cells in 5- and 10-day-old explants and in 10-day-old castrated rats suggests that: (i) the testicular androgens are not essential for their differentiation, (ii) a differential androgen dependence exists among the epididymal cell types, (iii) the undifferentiated epithelial cells are the precursors of the narrow cells. 相似文献
82.
Lavanya M Kinet S Montel-Hagen A Mongellaz C Battini JL Sitbon M Taylor N 《Journal of immunology (Baltimore, Md. : 1950)》2008,181(2):891-898
Bovine leukemia virus (BLV), one of the most common infectious viruses of cattle, is endemic in many herds. Approximately 30-40% of adult cows in the United States are infected by this oncogenic C-type retrovirus and 1-5% of animals will eventually develop a malignant lymphoma. BLV, like the human and simian T cell leukemia viruses, is a deltaretrovirus but, in contrast with the latter, the BLV receptor remains unidentified. In this study, we demonstrate that the amino-terminal 182 residues of the BLV envelope glycoprotein surface unit encompasses the receptor-binding domain. A bona fide interaction of this receptor-binding domain with the BLV receptor was demonstrated by specific interference with BLV, but not human T cell leukemia virus, envelope glycoprotein-mediated binding. We generated a rabbit Ig Fc-tagged BLV receptor-binding domain construct and ascertained that the ligand binds the BLV receptor on target cells from multiple species. Using this tool, we determined that the BLV-binding receptor is expressed on differentiating pro/pre-B cells in mouse bone marrow. However, the receptor was not detected on mature/quiescent B cells but was induced upon B cell activation. Activation of human B and T lymphocytes also induced surface BLV-binding receptor expression and required de novo protein synthesis. Receptor levels were down-regulated as activated lymphocytes returned to quiescence. In the human thymus, BLV-binding receptor expression was specifically detected on thymocytes responding to the IL-7 cytokine. Thus, expression of the BLV-binding receptor is a marker of enhanced metabolic activity in B cells, T cells, and thymocytes. 相似文献
83.
Manuel Etzkorn Manuela Zoonens Laurent J. Catoire Jean-Luc Popot Sebastian Hiller 《The Journal of membrane biology》2014,247(9-10):965-970
Amphipathic polymers called amphipols provide a valuable alternative to detergents for keeping integral membrane proteins soluble in aqueous buffers. Here, we characterize spatial contacts of amphipol A8-35 with membrane proteins from two architectural classes: The 8-stranded β-barrel outer membrane protein OmpX and the α-helical protein bacteriorhodopsin. OmpX is well structured in A8-35, with its barrel adopting a fold closely similar to that in dihexanoylphosphocholine micelles. The accessibility of A8-35-trapped OmpX by a water-soluble paramagnetic molecule is highly similar to that in detergent micelles and resembles the accessibility in the natural membrane. For the α-helical protein bacteriorhodopsin, previously shown to keep its fold and function in amphipols, NMR data show that the imidazole protons of a polyhistidine tag at the N-terminus of the protein are exchange protected in the presence of detergent and lipid bilayer nanodiscs, but not in amphipols, indicating the absence of an interaction in the latter case. Overall, A8-35 exhibits protein interaction properties somewhat different from detergents and lipid bilayer nanodiscs, while maintaining the structure of solubilized integral membrane proteins. 相似文献
84.
Loïck Le Dantec Gaelle Cardinet Julio Bonet Mathieu Fouché Karima Boudehri Amparo Monfort Jean-Luc Poëssel Annick Moing Elisabeth Dirlewanger 《Tree Genetics & Genomes》2010,6(6):995-1012
The goal of the present study was to identify candidate genes (CGs) involved in fruit quality in peach that can be transferred to other Rosaceae species. Two cDNA libraries from fruit of the “Fantasia” peach cultivar, constructed at two stages of development, were used to generate a set of expressed sequence tag sequences. A total of 1,730 peach unigenes were obtained after clustering. Sequences and corresponding annotations were stored in a relational database and are available through a web interface. Fifty-nine CGs involved in fruit growth and development or fruit quality at maturity, focusing on sweetness, acidity, and phenolic compound content, were selected according to their annotation. Fifty-five primer pairs, designed from peach CG sequences and giving PCR products in peach, were tested in strawberry and 36 gave amplified products. Eight CGs were mapped in peach, 14 in strawberry, four in both species and confirmed the pattern of synteny already proposed using comparative mapping. In peach, the CGs are located in three linkage groups (3, 5, 7), and in strawberry they are distributed in all seven Fragaria linkage groups. Colocalization between some of these CGs and quantitative trait loci for fruit quality traits were identified and are awaiting confirmation in further analyses. 相似文献
85.
Improvements in the usefulness of QTL analysis arise from better statistical methods applied to the problem, ability to analyze
more complex mating designs, and the fitting of less simplified genetic models. Here we review the advantages of different
plant mating designs in QTL analysis and conclude that diallel designs have several favorable properties. We then turn to
the detection of systematic genome-wide synergistic epistasis. This form of epistasis has important implications from evolutionary
(maintenance of sexual reproduction and concealment of cryptic genetic variation) and practical perspectives (response to
pyramided favorable alleles). We develop two methods for detecting systematic synergistic epistasis, one based on analyzing
interactions between locus effects and predicted individual genotypic values and one based on analyzing pairwise locus interactions.
Using the first method we detect synergistic epistasis in a barley and a wheat dataset but not in a maize dataset. We fail
to detect synergistic epistasis with the second method. We discuss our results in the light of theoretical questions concerning
the mechanisms of synergistic epistasis. 相似文献
86.
Perugi F Muriaux D Ramirez BC Chabani S Decroly E Darlix JL Blot V Pique C 《Molecular biology of the cell》2009,20(1):498-508
Human immunodeficiency virus (HIV)-1 replication is positively or negatively regulated through multiple interactions with host cell proteins. We report here that human Discs Large (Dlg1), a scaffold protein recruited beneath the plasma membrane and involved in the assembly of multiprotein complexes, restricts HIV-1 infectivity. The endogenous Dlg1 and HIV-1 Gag polyprotein spontaneously interact in HIV-1-chronically infected T cells. Depleting endogenous Dlg1 in either adherent cells or T cells does not affect Gag maturation, production, or release, but it enhances the infectivity of progeny viruses five- to sixfold. Conversely, overexpression of Dlg1 reduces virus infectivity by ~80%. Higher virus infectivity upon Dlg1 depletion correlates with increased Env content in cells and virions, whereas the amount of virus-associated Gag or genomic RNA remains identical. Dlg1 knockdown is also associated with the redistribution and colocalization of Gag and Env toward CD63 and CD82 positive vesicle-like structures, including structures that seem to still be connected to the plasma membrane. This study identifies both a new negative regulator that targets the very late steps of the HIV-1 life cycle, and an assembly pathway that optimizes HIV-1 infectivity. 相似文献
87.
Hamelin E Thériault C Laroche G Parent JL 《The Journal of biological chemistry》2005,280(43):36195-36205
Intracellular trafficking pathways of cell surface receptors following their internalization are the subject of intense research efforts. However, the mechanisms by which they recycle back to the cell surface are still poorly defined. We have recently demonstrated that the small Rab11 GTPase protein is a determinant factor in controlling the recycling to the cell surface of the beta-isoform of the thromboxane A2 receptor (TPbeta) following its internalization. Here, we demonstrate with co-immunoprecipitation studies in HEK293 cells that there is a Rab11-TPbeta association occurring in the absence of agonist, which is not modulated by stimulation of TPbeta. We show with purified TPbeta intracellular domains fused to GST and HIS-Rab11 proteins that Rab11 interacts directly with the first intracellular loop and the C-tail of TPbeta. Amino acids 335-344 of the TPbeta C-tail were determined to be essential for the interaction of Rab11 with this receptor domain. This identified sequence appears to be important in directing the intracellular trafficking of the receptor from the Rab5-positive intracellular compartment to the perinuclear recycling endosome. Interestingly, our data indicate that TPbeta interacts with the GDP-bound form, and not the GTP-bound form, of Rab11 which is necessary for recycling of the receptor back to the cell surface. To our knowledge, this is the first demonstration of a direct interaction between Rab11 and a transmembrane receptor. 相似文献
88.
González-Reiche AS Morales-Betoulle ME Alvarez D Betoulle JL Müller ML Sosa SM Perez DR 《PloS one》2012,7(3):e32873
The role wild bird species play in the transmission and ecology of avian influenza virus (AIV) is well established; however, there are significant gaps in our understanding of the worldwide distribution of these viruses, specifically about the prevalence and/or significance of AIV in Central and South America. As part of an assessment of the ecology of AIV in Guatemala, we conducted active surveillance in wild birds on the Pacific and Atlantic coasts. Cloacal and tracheal swab samples taken from resident and migratory wild birds were collected from February 2007 to January 2010.1913 samples were collected and virus was detected by real time RT-PCR (rRT-PCR) in 28 swab samples from ducks (Anas discors). Virus isolation was attempted for these positive samples, and 15 isolates were obtained from the migratory duck species Blue-winged teal. The subtypes identified included H7N9, H11N2, H3N8, H5N3, H8N4, and H5N4. Phylogenetic analysis of the viral sequences revealed that AIV isolates are highly similar to viruses from the North American lineage suggesting that bird migration dictates the ecology of these viruses in the Guatemalan bird population. 相似文献
89.
Pauline Chaste Nathalie Clement Oriane Mercati Jean-Luc Guillaume Richard Delorme Hany Goubran Botros Cécile Pagan Samuel Périvier Isabelle Scheid Gudrun Nygren Henrik Anckars?ter Maria Rastam Ola St?hlberg Carina Gillberg Emilie Serrano Nathalie Lemière Jean Marie Launay Marie Christine Mouren-Simeoni Marion Leboyer Christopher Gillberg Ralf Jockers Thomas Bourgeron 《PloS one》2010,5(7)
Melatonin is a powerful antioxidant and a synchronizer of many physiological processes. Alteration of the melatonin pathway has been reported in circadian disorders, diabetes and autism spectrum disorders (ASD). However, very little is known about the genetic variability of melatonin receptors in humans. Here, we sequenced the melatonin receptor MTNR1A and MTNR1B, genes coding for MT1 and MT2 receptors, respectively, in a large panel of 941 individuals including 295 patients with ASD, 362 controls and 284 individuals from different ethnic backgrounds. We also sequenced GPR50, coding for the orphan melatonin-related receptor GPR50 in patients and controls. We identified six non-synonymous mutations for MTNR1A and ten for MTNR1B. The majority of these variations altered receptor function. Particularly interesting mutants are MT1-I49N, which is devoid of any melatonin binding and cell surface expression, and MT1-G166E and MT1-I212T, which showed severely impaired cell surface expression. Of note, several mutants possessed pathway-selective signaling properties, some preferentially inhibiting the adenylyl cyclase pathway, others preferentially activating the MAPK pathway. The prevalence of these deleterious mutations in cases and controls indicates that they do not represent major risk factor for ASD (MTNR1A case 3.6% vs controls 4.4%; MTNR1B case 4.7% vs 3% controls). Concerning GPR50, we detected a significant association between ASD and two variations, Δ502–505 and T532A, in affected males, but it did not hold up after Bonferonni correction for multiple testing. Our results represent the first functional ascertainment of melatonin receptors in humans and constitute a basis for future structure-function studies and for interpreting genetic data on the melatonin pathway in patients. 相似文献
90.
Andrea Vivian Alvarez-Oxiley Noelita Melo de Sousa Jean-Luc Hornick Kamal Touati Gysbert C van der Weijden Marcel AM Taverne Otto Szenci Jean-François Beckers 《Acta veterinaria Scandinavica》2010,52(1):9