scholarly journals Homozygous Inactivating Mutation inNANOS3in Two Sisters with Primary Ovarian Insufficiency

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mariza G. Santos ◽  
Aline Z. Machado ◽  
Conceição N. Martins ◽  
Sorahia Domenice ◽  
Elaine M. F. Costa ◽  
...  

Despite the increasing understanding of female reproduction, the molecular diagnosis of primary ovarian insufficiency (POI) is seldom obtained. The RNA-binding protein NANOS3 poses as an interesting candidate gene for POI since members of the Nanos family have an evolutionarily conserved function in germ cell development and maintenance by repressing apoptosis. We performed mutational analysis ofNANOS3in a cohort of 85 Brazilian women with familial or isolated POI, presenting with primary or secondary amenorrhea, and in ethnically-matched control women. A homozygous p.Glu120Lys mutation inNANOS3was identified in two sisters with primary amenorrhea. The substituted amino acid is located within the second C2HC motif in the conserved zinc finger domain of NANOS3 andin silicomolecular modelling suggests destabilization of protein-RNA interaction.In vitroanalyses of apoptosis through flow cytometry and confocal microscopy show that NANOS3 capacity to prevent apoptosis was impaired by this mutation. The identification of an inactivating missense mutation inNANOS3suggests a mechanism for POI involving increased primordial germ cells (PGCs) apoptosis during embryonic cell migration and highlights the importance of NANOS proteins in human ovarian biology.

2020 ◽  
Author(s):  
Nan Zhang ◽  
Jiawei Xu ◽  
Xiao Bao ◽  
Feifei Zhao ◽  
Dayuan Shi ◽  
...  

Abstract Background: Primary ovarian insufficiency, one of the main causes of female infertility, is a heterogeneous disease when it comes to the phenotype and etiology. Familial cases are observed in approximately 10% of patients which indicates a strong genetic component. However, the underlying cause remains to be identified in most cases of patients.Methods: Here we studied an un-consanguineous Han Chinese family in which four siblings are primary amenorrhea and hypergonadotropic hypogonadism. Three siblings with POI and one unaffected sibling were exome sequenced. Also, other members in this family were genotyped by Sanger Sequencing. In silicon and in-vitro functional analyses were performed.Results: Whole exome sequencing identified a shared novel compound heterozygous mutation of FSHR gene in all the affected members. c.1412T>G, the first variant identified in FSHR IL2(intracellular loop2) in POI patients, and another novel mutation c.1090_1091del were the genetic etiology of this family. In-vitro functional analyses showed that cAMP (second messenger of FSHR) producing was abolished by c.1412T>G. Conclusions: Our study identified two novel FSHR mutations in a compound heterozygous state and gave the evidence that the FSHR IL2 could play a crucial role in FSHR-caused POI.


1999 ◽  
Vol 73 (9) ◽  
pp. 7357-7367 ◽  
Author(s):  
Debra Elton ◽  
Liz Medcalf ◽  
Konrad Bishop ◽  
Deborah Harrison ◽  
Paul Digard

ABSTRACT The influenza virus nucleoprotein (NP) is a single-strand-RNA-binding protein associated with genome and antigenome RNA and is one of the four virus proteins necessary for transcription and replication of viral RNA. To better characterize the mechanism by which NP binds RNA, we undertook a physical and mutational analysis of the polypeptide, with the strategy of identifying first the regions in direct contact with RNA, then the classes of amino acids involved, and finally the crucial residues by mutagenesis. Chemical fragmentation and amino acid sequencing of NP that had been UV cross linked to radiolabelled RNA showed that protein-RNA contacts occur throughout the length of the polypeptide. Chemical modification experiments implicated arginine but not lysine residues as important for RNA binding, while RNA-dependent changes in the intrinsic fluorescence spectrum of NP suggested the involvement of tryptophan residues. Supporting these observations, single-codon mutagenesis identified five tryptophan, one phenylalanine, and two arginine residues as essential for high-affinity RNA binding at physiological temperature. In addition, mutants unable to bind RNA in vitro were unable to support virus gene expression in vivo. The mutationally sensitive residues are not localized to any particular region of NP but instead are distributed throughout the protein. Overall, these data are inconsistent with previous models suggesting that the NP-RNA interaction is mediated by a discrete N-terminal domain. Instead, we propose that high-affinity binding of RNA by NP requires the concerted interaction of multiple regions of the protein with RNA and that the individual protein-RNA contacts are mediated by a combination of electrostatic interactions between positively charged residues and the phosphate backbone and planar interactions between aromatic side chains and bases.


Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1230
Author(s):  
Sawsan Napthine ◽  
Chris H. Hill ◽  
Holly C. M. Nugent ◽  
Ian Brierley

The product of the interferon-stimulated gene C19orf66, Shiftless (SHFL), restricts human immunodeficiency virus replication through downregulation of the efficiency of the viral gag/pol frameshifting signal. In this study, we demonstrate that bacterially expressed, purified SHFL can decrease the efficiency of programmed ribosomal frameshifting in vitro at a variety of sites, including the RNA pseudoknot-dependent signals of the coronaviruses IBV, SARS-CoV and SARS-CoV-2, and the protein-dependent stimulators of the cardioviruses EMCV and TMEV. SHFL also reduced the efficiency of stop-codon readthrough at the murine leukemia virus gag/pol signal. Using size-exclusion chromatography, we confirm the binding of the purified protein to mammalian ribosomes in vitro. Finally, through electrophoretic mobility shift assays and mutational analysis, we show that expressed SHFL has strong RNA binding activity that is necessary for full activity in the inhibition of frameshifting, but shows no clear specificity for stimulatory RNA structures.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jordy Homing Lam ◽  
Yu Li ◽  
Lizhe Zhu ◽  
Ramzan Umarov ◽  
Hanlun Jiang ◽  
...  

Abstract Protein-RNA interaction plays important roles in post-transcriptional regulation. However, the task of predicting these interactions given a protein structure is difficult. Here we show that, by leveraging a deep learning model NucleicNet, attributes such as binding preference of RNA backbone constituents and different bases can be predicted from local physicochemical characteristics of protein structure surface. On a diverse set of challenging RNA-binding proteins, including Fem-3-binding-factor 2, Argonaute 2 and Ribonuclease III, NucleicNet can accurately recover interaction modes discovered by structural biology experiments. Furthermore, we show that, without seeing any in vitro or in vivo assay data, NucleicNet can still achieve consistency with experiments, including RNAcompete, Immunoprecipitation Assay, and siRNA Knockdown Benchmark. NucleicNet can thus serve to provide quantitative fitness of RNA sequences for given binding pockets or to predict potential binding pockets and binding RNAs for previously unknown RNA binding proteins.


2000 ◽  
Vol 74 (18) ◽  
pp. 8252-8261 ◽  
Author(s):  
Hui Zhang ◽  
Roger J. Pomerantz ◽  
Geethanjali Dornadula ◽  
Yong Sun

ABSTRACT Virion infectivity factor (Vif) is a protein encoded by human immunodeficiency virus types 1 and 2 (HIV-1 and -2) and simian immunodeficiency virus, plus other lentiviruses, and is essential for viral replication either in vivo or in culture for nonpermissive cells such as peripheral blood lymphoid cells, macrophages, and H9 T cells. Defects in the vif gene affect virion morphology and reverse transcription but not the expression of viral components. It has been shown that Vif colocalizes with Gag in cells and Vif binds to the NCp7 domain of Gag in vitro. However, it seems that Vif is not specifically packaged into virions. The molecular mechanism(s) for Vif remains unknown. In this report, we demonstrate that HIV-1 Vif is an RNA-binding protein and specifically binds to HIV-1 genomic RNA in vitro. Further, Vif binds to HIV-1 RNA in the cytoplasm of virus-producing cells to form a 40S mRNP complex. Coimmunoprecipitation and in vivo UV cross-linking assays indicated that Vif directly interact with HIV-1 RNA in the virus-producing cells. Vif-RNA binding could be displaced by Gag-RNA binding, suggesting that Vif protein in the mRNP complex may mediate viral RNA interaction with HIV-1 Gag precursors. Furthermore, we have demonstrated that these Vif mutants that lose the RNA binding activity in vitro do not supportvif-deficient HIV-1 replication in H9 T cells, suggesting that the RNA binding capacity of Vif is important for its function. Further studies regarding Vif-RNA interaction in virus-producing cells will be important for studying the function of Vif in the HIV-1 life cycle.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Bushra Gorsi ◽  
Mika Moriwaki ◽  
Marvin B Moore ◽  
Aleksandar Rajkovic ◽  
Lawrence M Nelson ◽  
...  

Abstract Primary ovarian insufficiency (POI) is highly heritable. The majority of cases have no known cause. We hypothesized that mutations in previously identified genes or genes from the same pathways are the cause of POI in a recessive or dominant manner. Subjects included 294 women diagnosed with POI (amenorrhea with an elevated FSH level). All had a 46XX karyotype, and normal FMR1 repeat number. Subjects were recruited in Boston (n=95), at the NIH and Washington University (n=98), and in Pittsburgh (n=98). Controls included subjects recruited for health in old age and disorders unrelated to reproduction or cancer, and subjects from the 1000 Genomes Project (total n=587). Variants were called using the Sentieon software package (https://www.sentieon.com). Case and control samples were stratified on ethnicity, relatedness and heterozygosity. Peddy and XPAT were used to calculate quality control metrics to detect outlier samples for removal from analysis to create a homogenous dataset. The number of cases (227) and controls (458) was adjusted for downstream analysis. XPAT imposed additional quality filters and removed variants. A second filter removed variants that did not pass a Gnomad filter of <0.001 allele frequency. VAAST was used to determine a composite likelihood ratio (CLR) as the test statistic to represent the aggregate burden of variants of affected individuals in each transcript relative to a set of 458 control genomes. The significance of each transcript’s VAAST CLR score was evaluated by 1 million permutations. We screened exomes for variants in previously identified genes causing POI in humans and those demonstrating infertility in a male or female mouse model. We also used the American College of Medical Genetics and Genomics standards for interpretation of pathogenicity of a variant, with priority on null variants in genes with probability of loss of function intolerance based on the observed vs. expected rate in gnomAD, in vivo or in vitro functional evidence of a damaging effect, significantly increased prevalence compared to controls, i.e. not found in any controls or in fewer than 10 in the gnomAD database if the subject had a matching race/ethnicity. Thirty-four subjects were removed for poor quality exomes and relatedness. Fifty-three subjects had at least one variant in a previously identified POI gene or one in which there was a previously identified functional model. Two subjects carried recessive variants and 30 carried at least one novel heterozygous candidate variant for follow up. Analysis of genetic causes of POI in this large cohort identified candidate causal gene variants in over half of the subjects. The data demonstrate that the genetic architecture is heterogeneous. Although recessive mutations have been identified in consanguineous families, the data suggest that a dominant or oligogenic pattern of inheritance may be important.


2020 ◽  
Vol 26 (7) ◽  
pp. 485-497
Author(s):  
Diego Hernández-López ◽  
Adriana Geisinger ◽  
María Fernanda Trovero ◽  
Federico F Santiñaque ◽  
Mónica Brauer ◽  
...  

Abstract More than 50% of cases of primary ovarian insufficiency (POI) and nonobstructive azoospermia in humans are classified as idiopathic infertility. Meiotic defects may relate to at least some of these cases. Mutations in genes coding for synaptonemal complex (SC) components have been identified in humans, and hypothesized to be causative for the observed infertile phenotype. Mutation SYCE1 c.721C>T (former c.613C>T)—a familial mutation reported in two sisters with primary amenorrhea—was the first such mutation found in an SC central element component-coding gene. Most fundamental mammalian oogenesis events occur during the embryonic phase, and eventual defects are identified many years later, thus leaving few possibilities to study the condition’s etiology and pathogenesis. Aiming to validate an approach to circumvent this difficulty, we have used the CRISPR/Cas9 technology to generate a mouse model with an SYCE1 c.721C>T equivalent genome alteration. We hereby present the characterization of the homozygous mutant mice phenotype, compared to their wild type and heterozygous littermates. Our results strongly support a causative role of this mutation for the POI phenotype in human patients, and the mechanisms involved would relate to defects in homologous chromosome synapsis. No SYCE1 protein was detected in homozygous mutants and Syce1 transcript level was highly diminished, suggesting transcript degradation as the basis of the infertility mechanism. This is the first report on the generation of a humanized mouse model line for the study of an infertility-related human mutation in an SC component-coding gene, thus representing a proof of principle.


2005 ◽  
Vol 79 (11) ◽  
pp. 6631-6643 ◽  
Author(s):  
Diego E. Alvarez ◽  
María F. Lodeiro ◽  
Silvio J. Ludueña ◽  
Lía I. Pietrasanta ◽  
Andrea V. Gamarnik

ABSTRACT Secondary and tertiary RNA structures present in viral RNA genomes play essential regulatory roles during translation, RNA replication, and assembly of new viral particles. In the case of flaviviruses, RNA-RNA interactions between the 5′ and 3′ ends of the genome have been proposed to be required for RNA replication. We found that two RNA elements present at the ends of the dengue virus genome interact in vitro with high affinity. Visualization of individual molecules by atomic force microscopy reveled that physical interaction between these RNA elements results in cyclization of the viral RNA. Using RNA binding assays, we found that the putative cyclization sequences, known as 5′ and 3′ CS, present in all mosquito-borne flaviviruses, were necessary but not sufficient for RNA-RNA interaction. Additional sequences present at the 5′ and 3′ untranslated regions of the viral RNA were also required for RNA-RNA complex formation. We named these sequences 5′ and 3′ UAR (upstream AUG region). In order to investigate the functional role of 5′-3′ UAR complementarity, these sequences were mutated either separately, to destroy base pairing, or simultaneously, to restore complementarity in the context of full-length dengue virus RNA. Nonviable viruses were recovered after transfection of dengue virus RNA carrying mutations either at the 5′ or 3′ UAR, while the RNA containing the compensatory mutations was able to replicate. Since sequence complementarity between the ends of the genome is required for dengue virus viability, we propose that cyclization of the RNA is a required conformation for viral replication.


2004 ◽  
Vol 24 (17) ◽  
pp. 7392-7401 ◽  
Author(s):  
Jan Medenbach ◽  
Silke Schreiner ◽  
Sunbin Liu ◽  
Reinhard Lührmann ◽  
Albrecht Bindereif

ABSTRACT After each spliceosome cycle, the U4 and U6 snRNAs are released separately and are recycled to the functional U4/U6 snRNP, requiring in the mammalian system the U6-specific RNA binding protein p110 (SART3). Its domain structure is made up of an extensive N-terminal domain with at least seven tetratricopeptide repeat (TPR) motifs, followed by two RNA recognition motifs (RRMs) and a highly conserved C-terminal sequence of 10 amino acids. Here we demonstrate under in vitro recycling conditions that U6-p110 is an essential splicing factor. Recycling activity requires both the RRMs and the TPR domain but not the highly conserved C-terminal sequence. For U6-specific RNA binding, the two RRMs with some flanking regions are sufficient. Yeast two-hybrid assays reveal that p110 interacts through its TPR domain with the U4/U6-specific 90K protein, indicating a specific role of the TPR domain in spliceosome recycling. On the 90K protein, a short internal region (amino acids 416 to 550) suffices for the interaction with p110. Together, these data suggest a model whereby p110 brings together U4 and U6 snRNAs through both RNA-protein and protein-protein interactions.


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