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ring chromosome

Steen Kølvraa, Ripudaman Singh, Elizabeth A Normand, Sadeem Qdaisat, Ignatia B Van denVeyver, Laird Jackson, Lotte Hatt, Palle Schelde, Niels Uldbjerg, Else Marie Vestergaard, Li Zhao, Rui Chen, Chad A Shaw, Amy M Breman, Arthur L Beaudet
OBJECTIVE: Non-invasive prenatal testing (NIPT) based on fetal cells in maternal blood has the advantage over NIPT based on circulating cell-free fetal DNA in that there is no contamination with maternal DNA. This will most likely result in better detection of chromosomal aberrations including subchromosomal defects. The objective of this study was to test whether fetal cells enriched from maternal blood can be used for cell-based NIPT. METHODS: We present a method for enriching fetal cells from maternal blood, subsequent amplification of the fetal genome and detection of chromosomal and subchromosomal variations in the genome...
October 19, 2016: Prenatal Diagnosis
Magali De Koninck, Ana Losada
Cohesin is a large ring-shaped protein complex, conserved from yeast to human, which participates in most DNA transactions that take place in the nucleus. It mediates sister chromatid cohesion, which is essential for chromosome segregation and homologous recombination (HR)-mediated DNA repair. Together with architectural proteins and transcriptional regulators, such as CTCF and Mediator, respectively, it contributes to genome organization at different scales and thereby affects transcription, DNA replication, and locus rearrangement...
October 14, 2016: Cold Spring Harbor Perspectives in Medicine
Shane C Quinonez, Thomas D Gelehrter, Wendy R Uhlmann
Small supernumerary marker chromosomes (sSMC) are abnormal chromosomes that cannot be characterized by standard banding cytogenetic techniques. A minority of sSMC contain a neocentromere, which is an ectopic centromere lacking the characteristic alpha-satellite DNA. The phenotypic manifestations of sSMC and neocentromeric sSMC are variable and range from severe intellectual disability and multiple congenital anomalies to a normal phenotype. Here we report a patient with a diagnosis of Marfan syndrome and infertility found to have an abnormal karyotype consisting of a chromosome 15 deletion and a ring-type sSMC likely stabilized by a neocentromere derived via a mechanism initially described by Barbara McClintock in 1938...
October 14, 2016: American Journal of Medical Genetics. Part A
Andrea Carolina Torres, Verónica Vannini, Julieta Bonacina, Graciela Font, Lucila Saavedra, María Pía Taranto
BACKGROUND: Despite the fact that most vitamins are present in a variety of foods, malnutrition, unbalanced diets or insufficient intake of foods are still the cause of vitamin deficiencies in humans in some countries. Vitamin B12 (Cobalamin) is a complex compound that is only naturally produced by bacteria and archea. It has been reported that certain strains belonging to lactic acid bacteria group are capable of synthesized water-soluble vitamins such as those included in the B-group, as vitamin B12...
October 13, 2016: BMC Microbiology
Heather M Byers, Margaret P Adam, Amy LaCroix, Sarah E S Leary, Bonnie Cole, William B Dobyns, Heather C Mefford
Atypical teratoid rhabdoid tumors of the central nervous system are rare, highly malignant, embryonal tumors most often occurring in children under age 3 years. Most are due to a somatic change in tumor suppressor gene SMARCB1 followed by a second-hit, typically loss of heterozygosity, best detected on immunohistochemical staining. Despite the noteworthy genetic homogeneity of atypical teratoid rhabdoid tumors, relatively little is known about the oncogenic mechanisms that lead to biallelic inactivation of SMARCB1...
October 12, 2016: American Journal of Medical Genetics. Part A
Si-Sun Choi, Hee-Ju Nah, Hye-Rim Pyeon, Eung-Soo Kim
Tautomycetin (TMC) is a natural product with a linear structure that includes an ester bond connecting a dialkylmaleic moiety to a type I polyketide chain. Although TMC was originally identified as an antifungal antibiotic in the late 1980s, follow-up studies revealed its novel immunosuppressant activity. Specifically, TMC exhibited a mechanistically unique immunosuppressant activity about 100 times higher than that of cyclosporine A, a widely used immunosuppressant drug. Interestingly, a structurally close relative, tautomycin (TTM), was reported to not possess TMC-like immunosuppressant activity, suggesting that a distinctive polyketide moiety of TMC plays a critical role in immunosuppressant activity...
October 12, 2016: Journal of Industrial Microbiology & Biotechnology
Rima Koka, Candace B Mainor, Arnob Banerjee, Maria R Baer, Ying S Zou
No abstract text is available yet for this article.
October 12, 2016: Leukemia & Lymphoma
Brad A Krajina, Andrew J Spakowitz
Topological constraints, such as those associated with DNA supercoiling, play an integral role in genomic regulation and organization in living systems. However, physical understanding of the principles that underlie DNA organization at biologically relevant length scales remains a formidable challenge. We develop a coarse-grained simulation approach for predicting equilibrium conformations of supercoiled DNA. Our methodology enables the study of supercoiled DNA molecules at greater length scales and supercoiling densities than previously explored by simulation...
October 4, 2016: Biophysical Journal
Soon Bahng, Ryo Hayama, Kenneth J Marians
Properly condensed chromosomes are necessary for accurate segregation of the sisters after DNA replication. The Escherichia coli condesin is MukB, a Structural Maintenance of Chromosomes (SMC)3-like protein that forms a complex with MukE and the kleisin MukF. MukB is known to be able to mediate knotting of a DNA ring, an intramolecular reaction. In our investigations of how MukB condenses DNA we discovered that it can also mediate catenation of two DNA rings, an intermolecular reaction. This activity of MukB requires DNA binding by the head domains of the protein but does not require either ATP or its partner proteins MukE or MukF...
October 3, 2016: Journal of Biological Chemistry
Z Matijasevic, A Krzywicka-Racka, G Sluder, J Gallant, S N Jones
The MDMX (MDM4) oncogene is amplified or overexpressed in a significant percentage of human tumors. MDMX is thought to function as an oncoprotein by binding p53 tumor suppressor protein to inhibit p53-mediated transcription, and by complexing with MDM2 oncoprotein to promote MDM2-mediated degradation of p53. However, down-regulation or loss of functional MDMX has also been observed in a variety of human tumors that are mutated for p53, often correlating with more aggressive cancers and a worse patient prognosis...
October 3, 2016: Oncogenesis
Dina Elhadi, Li Lv, Xiao-Ran Jiang, Hong Wu, Guo-Qiang Chen
Microbial morphology engineering has recently become interesting for biotechnology. Genes ftsZ and mreB encoding proteins of bacterial fission ring and skeletons, respectively, are essential for cell growth, they both are the most important genes keeping the bacterial shapes including the cell length and width, respectively. Clustered regularly interspaced short palindromic repeats interference, abbreviated as CRISPRi, was for the first time used in this study to regulate expression intensities of ftsZ or/and mreB in E...
September 28, 2016: Metabolic Engineering
Roland G Huber, Irina Kulemzina, Keven Ang, Alap P Chavda, Sasikala Suranthran, Jun-Thing Teh, Dimitar Kenanov, Gaowen Liu, Giulia Rancati, Radoslaw Szmyd, Philipp Kaldis, Peter J Bond, Dmitri Ivanov
The cohesin ring, which is composed of the Smc1, Smc3, and Scc1 subunits, topologically embraces two sister chromatids from S phase until anaphase to ensure their precise segregation to the daughter cells. The opening of the ring is required for its loading on the chromosomes and unloading by the action of Wpl1 protein. Both loading and unloading are dependent on ATP hydrolysis by the Smc1 and Smc3 "head" domains, which engage to form two composite ATPase sites. Based on the available structures, we modeled the Saccharomyces cerevisiae Smc1/Smc3 head heterodimer and discovered that the Smc1/Smc3 interfaces at the two ATPase sites differ in the extent of protein contacts and stability after ATP hydrolysis...
September 27, 2016: Structure
Mohsen Cheki, Alireza Shirazi, Aziz Mahmoudzadeh, Javad Tavakkoly Bazzaz, Seyed Jalal Hosseinimehr
Metformin is a widely prescribed drug used in the treatment of patients with type 2 diabetes. In this study, the radioprotective effect of metformin was investigated against cytotoxicity and genotoxicity induced by ionizing radiation (IR) in human peripheral blood lymphocytes. Human lymphocytes were treated with metformin at concentrations 10 and 50μM for 2h and irradiated with 6MV X-rays. The radiation antagonistic potential of metformin was assessed by MTT [3-(4,5-dimethyl-2-thiaozolyl)-2,5-diphenyl-2H tetrazolium bromide] assay, chromosomal aberration (CA) analysis, cytokinesis blocked micronucleus (CBMN) assay, and flow cytometry...
October 2016: Mutation Research
Rui Gao, Lan Wang, Hao Cai, Jingjing Zhu, Long Yu
RNF12/RLIM is a RING domain-containing E3 ubiquitin ligase whose function has only begun to be elucidated recently. Although RLIM was reported to play important roles in some biological processes such as imprinted X-chromosome inactivation and regulation of TGF-β pathway etc., other functions of RLIM are largely unknown. Here, we identified RLIM as a novel E3 ubiquitin ligase for c-Myc, one of the most frequently deregulated oncoproteins in human cancers. RLIM associates with c-Myc in vivo and in vitro independently of the E3 ligase activity of RLIM...
2016: PloS One
Gioconda Manassero-Morales, Denisse Alvarez-Manassero, Alfredo Merino-Luna
Introduction. The coexistence of Down and Turner syndromes due to double chromosome aneuploidy is very rare; it is even more rare to find the presence of a double monoclonal chromosomal abnormality. Objective. To report a unique case of double monoclonal chromosomal abnormality with trisomy of chromosome 21 and an X ring chromosome in all cells studied; no previous report has been found. Case Report. Female, 28 months old, with pathological short stature from birth, with the following dysmorphic features: tilted upward palpebral fissures, short neck, brachycephaly, and low-set ears...
2016: Case Reports in Pediatrics
Michèle Valens, Axel Thiel, Frédéric Boccard
The Ori region of bacterial genomes is segregated early in the replication cycle of bacterial chromosomes. Consequently, Ori region positioning plays a pivotal role in chromosome dynamics. The Ori region of the E. coli chromosome is organized as a macrodomain with specific properties concerning DNA mobility, segregation of loci and long distance DNA interactions. Here, by using strains with chromosome rearrangements and DNA mobility as a read-out, we have identified the MaoP/maoS system responsible for constraining DNA mobility in the Ori region and limiting long distance DNA interactions with other regions of the chromosome...
September 2016: PLoS Genetics
Irina Kulemzina, Keven Ang, Xiaodan Zhao, Jun-Thing Teh, Vikash Verma, Sasikala Suranthran, Alap P Chavda, Roland G Huber, Birgit Eisenhaber, Frank Eisenhaber, Jie Yan, Dmitri Ivanov
Cohesin is a ring-shaped protein complex that is capable of embracing DNA. Most of the ring circumference is comprised of the anti-parallel intramolecular coiled coils of the Smc1 and Smc3 proteins, which connect globular head and hinge domains. Smc coiled coil arms contain multiple acetylated and ubiquitylated lysines. To investigate the role of these modifications, we substituted lysines for arginines to mimic the unmodified state and uncovered genetic interaction between the Smc arms. Using scanning force microscopy, we show that wild-type Smc arms associate with each other when the complex is not on DNA...
September 15, 2016: Molecular Cell
Xin-Jie Zhuang, Wen-Hao Tang, Xue Feng, Chang-Yu Liu, Jin-Liang Zhu, Jie Yan, De-Feng Liu, Ping Liu, Jie Qiao
ABSTARCT Formation of the XY body is believed to prevent recombination between X and Y chromosomes during meiosis. We recently demonstrated that SYCP3-like X-linked 2 (Slx2) could be involved in synaptonemal complex formation as well as XY body maintenance during meiosis. In order to further investigate the role and composition of XY body protein complexes in meiotic processes and spermatogenesis, a yeast 2-hybrid screening was performed, and the tripartite motif protein 27(Trim27) was found to interact with Slx2 and co-localized in the XY body...
October 2016: Cell Cycle
C S Paththinige, N D Sirisena, U G I U Kariyawasam, L P C Saman Kumara, V H W Dissanayake
A female child born preterm with intrauterine growth retardation and presenting with facial dysmorphism with clefts, microcephaly, limb deformities, and congenital abnormalities involving cardiovascular and urinary systems is described. Chromosomal analysis showed a de novo 46,XX,r(4)(p15.3q35) karyotype. The clinical features of the patient were compared with the phenotypic characteristics of 17 previously reported cases with ring chromosome 4 and those with Wolf-Hirschhorn syndrome (4p-). Clinical features observed in this case are consistent with the consensus phenotype in ring chromosome 4...
2016: Case Reports in Genetics
Jerry Vriend, Hassan Marzban
Chromosome 17 abnormalities are often observed in medulloblastomas (MBs), particularly those classified in the consensus Groups 3 and 4. Herein we review MB signature genes associated with chromosome 17 and the relationship of these signature genes to the ubiquitin-proteasome system. While clinical investigators have not focused on the ubiquitin-proteasome system in relation to MB, a substantial amount of data on the topic has been hidden in the form of supplemental datasets of gene expression. A supplemental dataset associated with the Thompson classification of MBs shows that a subgroup of MB with 17p deletions is characterized by reduced expression of genes for several core particle subunits of the beta ring of the proteasome (β1, β4, β5, β7)...
September 3, 2016: Cellular and Molecular Life Sciences: CMLS
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