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  • 1
    Language: English
    In: PLoS genetics, April 2017, Vol.13(4), pp.e1006725
    Description: [This corrects the article DOI: 10.1371/journal.pgen.1005975.].
    Keywords: Biology;
    E-ISSN: 1553-7404
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  • 2
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 2012, Vol.109(12), pp.4621-4626
    Description: The conserved RNA-binding protein Hfq and its associated small regulatory RNAs (sRNAs) are increasingly recognized as the players of a large network of posttranscriptional control of gene expression in Gram-negative bacteria. The role of Hfq in this network is to facilitate base pairing between sRNAs and their trans-encoded target mRNAs. Although the number of known sRNA–mRNA interactions has grown steadily, cellular factors that influence Hfq, the mediator of these interactions, have remained unknown. We report that RelA, a protein long known as the central regulator of the bacterial-stringent response, acts on Hfq and thereby affects the physiological activity of RyhB sRNA as a regulator of iron homeostasis. RyhB requires RelA in vivo to arrest growth during iron depletion and to down-regulate a subset of its target mRNAs (fdoG, nuoA, and sodA), whereas the sodB and sdhC targets are barely affected by RelA. In vitro studies with recombinant proteins show that RelA enhances multimerization of Hfq monomers and stimulates Hfq binding of RyhB and other sRNAs. Hfq from polysomes extracted from wild-type cells binds RyhB in vitro, whereas Hfq from polysomes of a relA mutant strain shows no binding. We propose that, by increasing the level of the hexameric form of Hfq, RelA enables binding of RNAs whose affinity for Hfq is low. Our results suggest that, under specific conditions and/or environments, Hfq concentrations are limiting for RNA binding, which thereby provides an opportunity for cellular proteins such as RelA to impact sRNA-mediated responses by modulating the activity of Hfq. ; p. 4621-4626.
    Keywords: Polyribosomes ; In Vitro Studies ; Messenger Rna ; Gram-Negative Bacteria ; Gene Expression ; Recombinant Proteins
    ISSN: 0027-8424
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  • 3
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 20 March 2012, Vol.109(12), pp.4621-6
    Description: The conserved RNA-binding protein Hfq and its associated small regulatory RNAs (sRNAs) are increasingly recognized as the players of a large network of posttranscriptional control of gene expression in Gram-negative bacteria. The role of Hfq in this network is to facilitate base pairing between sRNAs and their trans-encoded target mRNAs. Although the number of known sRNA-mRNA interactions has grown steadily, cellular factors that influence Hfq, the mediator of these interactions, have remained unknown. We report that RelA, a protein long known as the central regulator of the bacterial-stringent response, acts on Hfq and thereby affects the physiological activity of RyhB sRNA as a regulator of iron homeostasis. RyhB requires RelA in vivo to arrest growth during iron depletion and to down-regulate a subset of its target mRNAs (fdoG, nuoA, and sodA), whereas the sodB and sdhC targets are barely affected by RelA. In vitro studies with recombinant proteins show that RelA enhances multimerization of Hfq monomers and stimulates Hfq binding of RyhB and other sRNAs. Hfq from polysomes extracted from wild-type cells binds RyhB in vitro, whereas Hfq from polysomes of a relA mutant strain shows no binding. We propose that, by increasing the level of the hexameric form of Hfq, RelA enables binding of RNAs whose affinity for Hfq is low. Our results suggest that, under specific conditions and/or environments, Hfq concentrations are limiting for RNA binding, which thereby provides an opportunity for cellular proteins such as RelA to impact sRNA-mediated responses by modulating the activity of Hfq.
    Keywords: Escherichia Coli -- Metabolism ; Escherichia Coli Proteins -- Physiology ; Host Factor 1 Protein -- Physiology ; Ligases -- Physiology ; RNA, Bacterial -- Metabolism ; RNA-Binding Proteins -- Physiology
    ISSN: 00278424
    E-ISSN: 1091-6490
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  • 4
    In: PLoS Genetics, 2016, Vol.12(4)
    Description: While an increasing number of conserved small regulatory RNAs (sRNAs) are known to function in general bacterial physiology, the roles and modes of action of sRNAs from horizontally acquired genomic regions remain little understood. The IsrK sRNA of Gifsy-1 prophage of Salmonella belongs to the latter class. This regulatory RNA exists in two isoforms. The first forms, when a portion of transcripts originating from isrK promoter reads-through the IsrK transcription-terminator producing a translationally inactive mRNA target. Acting in trans , the second isoform, short IsrK RNA, binds the inactive transcript rendering it translationally active. By switching on translation of the first isoform, short IsrK indirectly activates the production of AntQ, an antiterminator protein located upstream of isrK . Expression of antQ globally interferes with transcription termination resulting in bacterial growth arrest and ultimately cell death. Escherichia coli and Salmonella cells expressing AntQ display condensed chromatin morphology and localization of UvrD to the nucleoid. The toxic phenotype of AntQ can be rescued by co-expression of the transcription termination factor, Rho, or RNase H, which protects genomic DNA from breaks by resolving R-loops. We propose that AntQ causes conflicts between transcription and replication machineries and thus promotes DNA damage. The isrK locus represents a unique example of an island-encoded sRNA that exerts a highly complex regulatory mechanism to tune the expression of a toxic protein. Author Summary As the function of conserved core-genome-encoded small RNAs (sRNA) reflects the basic lifestyle of bacteria, the function of non-conserved island-encoded sRNAs remains enigmatic. The island-encoded sRNA IsrK belongs to Gifsy-1 prophage of Salmonella . Here, we report a complex mechanism in which the IsrK RNA functions as both sRNA and mRNA to control the production of the toxic AntQ protein. The isrK promoter directs the synthesis of two distinct RNA species: a full-length translationally inactive target mRNA and the correctly terminated, shorter IsrK sRNA. IsrK sRNA binds the full-length inactive mRNA producing an antiterminator protein, AntQ, which interferes with transcription termination. Expression of antQ results in bacterial growth arrest and ultimately cell death. Fluorescence microscopy of E . coli and Salmonella expressing antQ revealed condensed chromatin morphology as observed upon exposure to DNA-damaging agents. We propose that expression of the phage antiterminator protein results in conflicts between transcription and replication machineries and thus facilitates DNA damage. In summary, the RNA regulator IsrK presents a new regulatory principle in which a horizontally acquired sRNA controls genome integrity.
    Keywords: Research Article ; Biology And Life Sciences ; Biology And Life Sciences ; Medicine And Health Sciences ; Biology And Life Sciences ; Medicine And Health Sciences ; Biology And Life Sciences ; Biology And Life Sciences ; Biology And Life Sciences ; Research And Analysis Methods ; Biology And Life Sciences ; Biology And Life Sciences ; Research And Analysis Methods ; Research And Analysis Methods ; Biology And Life Sciences
    ISSN: 1553-7390
    E-ISSN: 1553-7404
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  • 5
    Language: English
    Description: While an increasing number of conserved small regulatory RNAs (sRNAs) are known to function in general bacterial physiology, the roles and modes of action of sRNAs from horizontally acquired genomic regions remain little understood. The IsrK sRNA of Gifsy-1 prophage of Salmonella belongs to the latter class. This regulatory RNA exists in two isoforms. The first forms, when a portion of transcripts originating from isrK promoter reads-through the IsrK transcription-terminator producing a translationally inactive mRNA target. Acting in trans, the second isoform, short IsrK RNA, binds the inactive transcript rendering it translationally active. By switching on translation of the first isoform, short IsrK indirectly activates the production of AntQ, an antiterminator protein located upstream of isrK. Expression of antQ globally interferes with transcription termination resulting in bacterial growth arrest and ultimately cell death. Escherichia coli and Salmonella cells expressing AntQ display condensed chromatin morphology and localization of UvrD to the nucleoid. The toxic phenotype of AntQ can be rescued by co-expression of the transcription termination factor, Rho, or RNase H, which protects genomic DNA from breaks by resolving R-loops. We propose that AntQ causes conflicts between transcription and replication machineries and thus promotes DNA damage. The isrK locus represents a unique example of an island-encoded sRNA that exerts a highly complex regulatory mechanism to tune the expression of a toxic protein.
    Source: Open Access LMU (Universitätsbibliothek der LMU München)
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  • 6
    Language: English
    In: Fertility and Sterility, 01 September 2016, Vol.106(3), pp.590-596.e2
    Description: To evaluate the safety of oocyte activation by calcium ionophore in cases of failed fertilization after intracytoplasmic sperm injection (ICSI) procedure with respect to birth defects. A retrospective cohort of pregnancies achieved by oocyte activation with calcium ionophore after ICSI (ICSI-Ca) and routine ICSI between the years 2006 and 2014. Not applicable. The cohort included a total of 793 pregnancies: 66 (8%) were lost to follow up and 49 (6%) were ongoing pregnancies at the time of data collection. Out of the 678 available cases for analysis, 595 treatments were ICSI alone (88%) and 83 were ICSI-Ca (12%). None. Pregnancy and neonatal outcomes including birth defects were compared. On the basis of a cohort of 595 ICSI pregnancies and 83 ICSI-Ca pregnancies, we found no difference in birth defects rate for singletons or for twins. Additionally, no significant difference was found between defect type (chromosomal aberration or structural malformations) and malformation type (heart, urogenital, and limb), between the ICSI and ICSI-Ca groups. Moreover, no significant differences were found regarding birth weight, gestational week at time of delivery, and fetal gender for singleton or twin pregnancies. Ca ionophore oocyte activation should be considered as a legitimate option for cases of failed or low fertilization by ICSI.
    Keywords: Intracytoplasmic Sperm Injection ; Icsi ; Artificial Oocyte Activation ; AOA ; Congenital Defects ; Medicine
    ISSN: 0015-0282
    E-ISSN: 1556-5653
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  • 7
    Language: English
    In: PLoS ONE, May 22, 2018, Vol.13(5), p.e0196706
    Description: Background Neutrophils to lymphocytes ratio (NLR) and platelets to lymphocytes ratio (PLR) are both inflammatory ratios that can be easily calculated from a simple blood count. They are frequently reported and tested as prognostic factors in several medical disciplines. Pregnancy involves special reference values for laboratory assays. Objective The aim of this study was to define pregnancy-related reference values for NLR and PLR according to trimester, background morbidity and according to the patient's age. Study design A retrospective analysis of a large cohort undergoing community-based pregnancy surveillance between the years 2011-2016. Data were analyzed according to high-risk patient versus normal-risk patient. Results A total of 11,415 patients were included. Mean PLR and NLR values were 136.3#177;44.3, 2.6#177;1, respectively during the first trimester, 144.6#177;47.1, 4.0#177;1.4 respectively during the second trimester and 118.1#177;42.0, 3.5#177;1.2 respectively during the third trimester. No difference was detected between the high-risk and the normal population (P-values 0.3, 0.5 and 0.4 for PLR in each trimester respectively and 0.3, 0.4, 0.6 for NLR in each trimester, respectively). No differences were detected among parity categories. The correlation between patient's age and either PLR and NLR was a weak positive correlation (though statistically significant). Both PLR and NLR reached a maximum value during the second trimester. The differences between mean NLR and PLR between trimesters were significant (P 0.01 for all differences tested). PLR rises in the presence of anemia, reaching statistical significance (P-value for PLR in each trimester was 0.01). NLR showed an opposite trend (P-values for NLR were 0.4, 0.005 and 0.06 in each trimester, respectively). Conclusions In our cohort, there were generally no differences between the high-risk and the normal population, excluding patients with a fibroid uterus or inflammatory bowel disease who presented a significantly elevated PLR through all trimesters. Both PLR and NLR reached a maximum value during the second trimester and were positively correlated with age. We anticipate that the population-based data will assist in providing accurate reference values for future research testing NLR and PLR measures during pregnancy.
    Keywords: Pregnancy – Health Aspects ; Inflammatory Bowel Diseases – Diagnosis ; Lymphocytes – Research ; Neutrophils – Research
    ISSN: 1932-6203
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  • 8
    Language: English
    In: The Israel Medical Association journal : IMAJ, June 2013, Vol.15(6), pp.321-2
    Keywords: Leukoencephalopathy, Progressive Multifocal ; Antibodies, Monoclonal, Murine-Derived -- Adverse Effects ; Jc Virus -- Physiology ; Lymphoma, Large B-Cell, Diffuse -- Drug Therapy
    ISSN: 1565-1088
    Source: MEDLINE/PubMed (U.S. National Library of Medicine)
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  • 9
    Language: English
    In: Journal of Assisted Reproduction and Genetics, 2018, Vol.35(1), pp.143-148
    Description: Purpose The purpose of this study was to evaluate telomere homeostasis in sub-fertile compared to fertile human sperm. Methods This observational, comparative study included 16 sub-fertile men who required intracytoplasmic sperm injection and 10 fertile men. At least 100 sperm cells from each participant were assessed. Main outcome measures were telomere length and telomere aggregates. Telomerase RNA component (TERC) copy number and telomere capture were assessed using fluorescence in situ hybridization technique and human telomerase reverse transcriptase (hTERT) using immunohistochemistry. Results Clinical backgrounds were similar. The percentage of sperm cells with shorter telomeres was higher among the sub-fertile compared to the fertile participants (3.3 ± 3.1 vs. 0.6 ± 1.2%, respectively; P 〈 0.005). The percentage of cells with telomere aggregates was significantly higher in the sub-fertile group (15.12 ± 3.73 vs. 4.73 ± 3.73%; P 〈 0.005). TERC gene copy number was similar between groups. The percentage of cells that were positive for hTERT was lower in the sub-fertile group (3.81 ± 1.27 vs. 8.42 ± 1.80%; P 〈 0.005). Telomere capture rates were higher among the sub-fertile sperm cells (P 〈 0.005). Conclusions Sub-fertile sperm cells have short telomeres that are elongated by the alternative pathway of telomere capture. Dysfunctional telomeres may affect sperm fertilizability.
    Keywords: Male sub-fertility ; Telomeres ; Sperm
    ISSN: 1058-0468
    E-ISSN: 1573-7330
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  • 10
    Language: English
    In: Archives of Gynecology and Obstetrics, 2018, Vol.298(1), pp.51-58
    Description: To access, purchase, authenticate, or subscribe to the full-text of this article, please visit this link: http://dx.doi.org/10.1007/s00404-018-4747-z Byline: Rivka Sukenik Halevy (1,2,3), Jordana Mashiach Friedler (4), Anat Hershko-Klement (1,3), Tal Biron-Shental (1,3), Ofer Markovitch (3,4), Ronnie Tepper (3,4) Keywords: Lateral neck cyst; Aneuploidy; Heart malformations; Pregnancy outcome Abstract: Purpose This study evaluated the association of fetal lateral neck cysts (FLNC) with adverse pregnancy outcomes, in relation to specific sonographic characteristics and co-existing findings. Methods Pregnancies in which FLNC were detected by a single examiner in early anatomical scans (14--16 weeks) were included. Data regarding the pregnancy and its outcome were retrieved from telephone-based questionnaires, patient charts and from the examiner's reports. Results 654 cases of FLNC were detected among 9446 early anatomical scans (6.9%). Complete data regarding 219 pregnancies were available. FLNC were significantly more prevalent in males (65.2%). The prevalence of heart malformations was 3.2% [all were non-isolated cases or with abnormal nuchal translucency (NT) and/or nuchal fold (NF)]. Amniocentesis performed in 165 pregnancies was abnormal in 1.2%. Among 206 children born from this cohort, adverse medical outcomes were reported in 5.3%. The likelihood of adverse pregnancy outcomes was significantly higher in non-isolated cases and in cases with abnormal NT or NF. Sonographic characteristics such as cyst size and bilateral findings were not linked to adverse pregnancy outcomes. Conclusion Isolated FLNC are benign findings which do not require additional work up. FLNC with additional sonographic abnormalities are associated with a significantly increased risk for adverse pregnancy outcomes. Author Affiliation: (1) 0000 0001 0325 0791, grid.415250.7, Department of OB-GYN, Meir Medical Center, Kfar Saba, Israel (2) 0000 0001 0325 0791, grid.415250.7, Genetics Institute, Meir Medical Center, 59 Tchernichovsky St., Kfar Saba, Israel (3) 0000 0004 1937 0546, grid.12136.37, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel (4) 0000 0001 0325 0791, grid.415250.7, Ultrasound Unit, Meir Medical Center, Kfar Saba, Israel Article History: Registration Date: 13/03/2018 Received Date: 30/11/2017 Accepted Date: 12/03/2018 Online Date: 03/04/2018
    Keywords: Lateral neck cyst ; Aneuploidy ; Heart malformations ; Pregnancy outcome
    ISSN: 0932-0067
    E-ISSN: 1432-0711
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