40 research outputs found

    Potential of DNA zygosity tests for non-invasive evaluation of risk of complications in twin pregnancies

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    Objectives: To evaluate and compare the potential of DNA analysis and ultrasound examination for diagnosis of high-risk and low-risk twin pregnancies. Material and methods: Chorionicity of 42 twin pregnancies was determined by routine high-resolution sonographic examination between 10 and 14 weeks of gestation. Zygosity was analysed in umbilical cord blood samples collected immediately after the birth by genotyping of 22 autosomal short tandem repeats used in human identity testing. Results: Routine ultrasound imaging in the first trimester of twin gestations revealed 21 low-risk dichorionic (50%) and 21 high-risk monochorionic pregnancies (50%). DNA typing of umbilical cord blood showed 23 twin pairs with different genotypes (low-risk dizygotic pregnancies, 55%) and 19 twin pairs with identical genotypes (high-risk monozygotic pregnancies, 45%). We found four pregnancies (10%), which were diagnosed sonographically as monochorionic diamniotic, but were identified as dizygotic in postnatal DNA testing. They constituted 19% of all high-risk monochorionic pregnancies detected by ultrasound imaging. Conclusions: Our results indicate high potential of prenatal DNA testing of zygosity in identification of low-risk and high-risk twin gestations requiring different prenatal care, especially in cases when chorionicity and zygosity cannot be reliably determined by ultrasound examination and as a supplementary test able to detect gestations misdiagnosed as monochorionic, resulting from fusions of dizygotic placentas. In such cases, dizygosity detected prenatally eliminates the need for frequent prenatal visits typical for monochorionic pregnancies. If chorionicity cannot be unequivocally determined and a prenatal DNA test detects monozygotic twins, a more pessimistic variant of monochorionic pregnancy should always be assumed

    CRISPR activation screen in mice identifies novel membrane proteins enhancing pulmonary metastatic colonisation

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    Abstract Melanoma represents ~5% of all cutaneous malignancies, yet accounts for the majority of skin cancer deaths due to its propensity to metastasise. To develop new therapies, novel target molecules must to be identified and the accessibility of cell surface proteins makes them attractive targets. Using CRISPR activation technology, we screened a library of guide RNAs targeting membrane protein-encoding genes to identify cell surface molecules whose upregulation enhances the metastatic pulmonary colonisation capabilities of tumour cells in vivo. We show that upregulated expression of the cell surface protein LRRN4CL led to increased pulmonary metastases in mice. Critically, LRRN4CL expression was elevated in melanoma patient samples, with high expression levels correlating with decreased survival. Collectively, our findings uncover an unappreciated role for LRRN4CL in the outcome of melanoma patients and identifies a potential therapeutic target and biomarker.info:eu-repo/semantics/publishe

    FBXO7 sensitivity of phenotypic traits elucidated by a hypomorphic allele.

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    FBXO7 encodes an F box containing protein that interacts with multiple partners to facilitate numerous cellular processes and has a canonical role as part of an SCF E3 ubiquitin ligase complex. Mutation of FBXO7 is responsible for an early onset Parkinsonian pyramidal syndrome and genome-wide association studies have linked variants in FBXO7 to erythroid traits. A putative orthologue in Drosophila, nutcracker, has been shown to regulate the proteasome, and deficiency of nutcracker results in male infertility. Therefore, we reasoned that modulating Fbxo7 levels in a murine model could provide insights into the role of this protein in mammals. We used a targeted gene trap model which retained 4-16% residual gene expression and assessed the sensitivity of phenotypic traits to gene dosage. Fbxo7 hypomorphs showed regenerative anaemia associated with a shorter erythrocyte half-life, and male mice were infertile. Alterations to T cell phenotypes were also observed, which intriguingly were both T cell intrinsic and extrinsic. Hypomorphic mice were also sensitive to infection with Salmonella, succumbing to a normally sublethal challenge. Despite these phenotypes, Fbxo7 hypomorphs were produced at a normal Mendelian ratio with a normal lifespan and no evidence of neurological symptoms. These data suggest that erythrocyte survival, T cell development and spermatogenesis are particularly sensitive to Fbxo7 gene dosage

    The AMP-activated protein kinase beta 1 subunit modulates murine erythrocyte development

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    Failure to maintain a normal in vivo erythrocyte half-life results in the development of hemolytic anemia. Half-life is affected by numerous factors, including energy balance, electrolyte gradients, reactive oxygen species, and membrane plasticity. The heterotrimeric AMP-activated protein kinase (AMPK) is an evolutionarily conserved serine/threonine kinase that acts as a critical regulator of cellular energy balance. Previous roles for the alpha 1 and gamma 1 subunits in the control of erythrocyte survival have been reported. In the work described here, we studied the role of the beta 1 subunit in erythrocytes and observed microcytic anemia with compensatory extramedullary hematopoiesis together with splenomegaly and increased osmotic resistance

    Intrauterine deaths — an unsolved problem in Polish perinatology

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    Objectives: The Polish criteria for “intrauterine death” include fetal demise after 22 weeks of gestation, weighing > 500 g and body length at least 25 cm, when the gestational age is unknown. The rate of fetal death in Poland in 2015 is 3:10,000. In 2020, 1,231 stillbirths were registered. Material and methods: An analysis using 142,662 births in the period between 2015–2020 in 11 living in Poland. The first subgroup was admitted as patients > 22 to the beginning of the 30th week of pregnancy (n = 229), and the second from the 30th week of pregnancy inclusively (n = 179). In the case of women from both subgroups, there was a risk of preterm delivery close to hospitalization. Results: It was found that stillbirth in 41% of women in the first pregnancy. For the patient, stillbirth was also the first in his life. The average stillbirth weight was 1487 g, the average body length was 40 cm. Among fetuses up to 30 weeks, male fetuses are born more often, in subgroup II, the sex of the child was usually female. Most fetal deaths occur in mothers < 15 and > 45 years of age. Conclusions: According to the Polish results of the origin of full-term fetuses > 30 weeks of gestation for death in the concomitant antenatal, such as placental-umbilical and fetal hypoxia, acute intrapartum effects rarely, and moreover < 30 Hbd fetal growth restriction (FGR), occurring placental-umbilical, acute intrapartum often

    Variants of the 5′-terminal region of p53 mRNA influence the ribosomal scanning and translation efficiency

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    Abstract The p53 protein is one of the major cell cycle regulators. The protein is expressed as at least twelve protein isoforms resulting from the use of alternative promoters, alternative splicing or downstream initiation codons. Importantly, there is growing evidence that translation initiation of p53 mRNA may be regulated by the structure and length of the naturally occurring variants of the 5′-terminal region of p53 mRNA transcripts. Here, several mRNA constructs were synthesized with variable length of the p53 5′-terminal regions and encoding luciferase reporter protein, and their translation was monitored continuously in situ in a rabbit reticulocyte lysate system. Moreover, four additional mRNA constructs were prepared. In two constructs, the structural context of AUG1 initiation codon was altered while in the other two constructs, characteristic hairpin motifs present in the p53 5′-terminal region were changed. Translation of the last two constructs was also performed in the presence of the cap analogue to test the function of the 5′-terminal region in cap-independent translation initiation. Superposition of several structural factors connected with the length of the 5′-terminal region, stable elements of the secondary structure, structural environment of the initiation codon and IRES elements greatly influenced the ribosomal scanning and translation efficiency

    The Role of Structural Elements of the 5'-Terminal Region of p53 mRNA in Translation under Stress Conditions Assayed by the Antisense Oligonucleotide Approach.

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    The p53 protein is one of the major factors responsible for cell cycle regulation and stress response. In the 5'-terminal region of p53 mRNA, an IRES element has been found which takes part in the translational regulation of p53 expression. Two characteristic hairpin motifs are present in this mRNA region: G56-C169, with the first AUG codon, and U180-A218, which interacts with the Hdm2 protein (human homolog of mouse double minute 2 protein). 2'-OMe modified antisense oligomers hybridizing to the 5'-terminal region of p53 mRNA were applied to assess the role of these structural elements in translation initiation under conditions of cellular stress. Structural changes in the RNA target occurring upon oligomers' binding were monitored by the Pb2+-induced cleavage method. The impact of antisense oligomers on the synthesis of two proteins, the full-length p53 and its isoform Δ40p53, was analysed in HT-29, MCF-7 and HepG2 cells, under normal conditions and under stress, as well as in vitro conditions. The results revealed that the hairpin U180-A218 and adjacent single-stranded region A219-A228 were predominantly responsible for high efficacy of IRES-mediated translation in the presence of stress factors. These motifs play a role of cis-acting elements which are able to modulate IRES activity, likely via interactions with protein factors
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