scholarly journals Analysis of Extrachromosomal Ac/Ds Transposable Elements

Genetics ◽  
2000 ◽  
Vol 155 (1) ◽  
pp. 349-359 ◽  
Author(s):  
Vera Gorbunova ◽  
Avraham A Levy
Keyword(s):  
Random Sequence ◽  
Donor Site ◽  
Plasmid Rescue ◽  
Present Evidence ◽  
Extrachromosomal Elements ◽  
Linear Elements ◽  
Ds Excision ◽  
Hairpin Formation ◽  
Insight Into ◽  
Original Donor

Abstract The mechanism of transposition of the maize Ac/Ds elements is not well understood. The true transposition intermediates are not known and it has not been possible to distinguish between excision models involving 8-bp staggered cuts or 1-bp staggered cuts followed by hairpin formation. In this work, we have analyzed extrachromosomal excision products to gain insight into the excision mechanism. Plasmid rescue was used to demonstrate that Ds excision is associated with the formation of circular molecules. In addition, we present evidence for the formation of linear extrachromosomal species during Ds excision. Sequences found at the termini of circular and linear elements showed a broad range of nucleotide additions or deletions, suggesting that these species are not true intermediates. Additional nucleotides adjacent to the termini in extrachromosomal elements were compared to the sequence of the original donor site. This analysis showed that: (1) the first nucleotide adjacent to the transposon end was significantly more similar to the first nucleotide flanking the element in the donor site than to a random sequence and (2) the second and farther nucleotides did not resemble the donor site. The implications of these findings for excision models are discussed.

scholarly journals Genetic evidence against intramolecular rejoining of the donor DNA molecule following IS10 transposition.

Genetics ◽  
1991 ◽  
Vol 128 (4) ◽  
pp. 687-694
Author(s):  
J Bender ◽  
J Kuo ◽  
N Kleckner
Keyword(s):  
Donor Site ◽  
Bacterial Genome ◽  
Strand Break ◽  
Donor Molecule ◽  
Dna Molecule ◽  
Target Dna ◽  
Donor Locus ◽  
Is10 Element ◽  
Original Donor ◽  
Original Information

Abstract Tn10 and IS10 transpose by a nonreplicative mechanism in which the transposon is excised from the donor molecule and integrated into a target DNA site, leaving behind a break at the original donor site. The fate of this broken donor DNA molecule is not known. We describe here two experiments that address this issue. One experiment demonstrates that a polar IS10 element gives rise to polarity-relief revertants at less than 1% the frequency of transposition of the same element in the same culture. In a second experiment, transpositions of an IS10 element from one site in the bacterial genome to another are selected and the resulting isolates examined for alterations at the donor site; none of 1088 such isolates exhibited a detectable change at the donor locus. These results are compatible with two possible fates of the transposon donor molecule: degradation ("donor suicide"), or restoration of the original information at the donor site by a recombinational repair mechanism analogous to double-strand break repair. These results argue against the possibility that the donor molecule gap is simply resealed by intramolecular rejoining.

MicroRNA: mIR-ly regulators of DNMT?

Blood ◽  
2009 ◽  
Vol 113 (25) ◽  
pp. 6269-6270 ◽  
Author(s):  
Elizabeth A. Griffiths ◽  
Steven D. Gore
Keyword(s):  
Mechanism Of Action ◽  
Functional Role ◽  
Present Evidence ◽  
Pharmacologically Active ◽  
Insight Into

Abstract In this issue of Blood, Garzon and colleagues present evidence for a functional role of miR 29b in controlling DNMT levels in leukemia. Their work may provide insight into the mechanism of action of the azanucleotides and could potentially offer the first pharmacologically active miRNA.

scholarly journals Random Binary Sequences in Telecommunications

2013 ◽  
Vol 64 (4) ◽  
pp. 230-237 ◽  
Author(s):  
Slavko Šajić ◽  
Nebojša Maletić ◽  
Branislav M. Todorović ◽  
Milan Šunjevarić
Keyword(s):  
Random Sequence ◽  
Binary Sequence ◽  
Statistical Test ◽  
Binary Sequences ◽  
Secure Communications ◽  
Basic Principles ◽  
Sequence Generation ◽  
Telecommunication Systems ◽  
Random Sequence Generation ◽  
Insight Into

Realization of modern telecommunication systems is inconceivable without use of different binary sequences. In this paper, an overview of random binary sequences used in different telecommunication systems is given. Basic principles of pseudorandom, chaotic, and true random sequence generation are presented, as well as their application in telecommunications in respect to advantages and drawbacks of the same. Moreover, particular scheme for true random binary sequence generation is given, as well as results of randomness assessment obtained by NIST statistical test suite. Finally, short insight into importance of random binary sequence in secure communications is given.

scholarly journals Topoisomerase II SUMOylation activates a metaphase checkpoint via Haspin and Aurora B kinases

2019 ◽  
Vol 219 (1) ◽  
Author(s):  
Nootan Pandey ◽  
Daniel Keifenheim ◽  
Makoto Michael Yoshida ◽  
Victoria A. Hassebroek ◽  
Caitlin Soroka ◽  
...  
Keyword(s):  
Topoisomerase Ii ◽  
Histone H3 ◽  
Aurora B ◽  
Additional Time ◽  
Checkpoint Activation ◽  
Present Evidence ◽  
The Core ◽  
Anaphase Onset ◽  
Topo Ii ◽  
Insight Into

Topoisomerase II (Topo II) is essential for mitosis since it resolves sister chromatid catenations. Topo II dysfunction promotes aneuploidy and drives cancer. To protect from aneuploidy, cells possess mechanisms to delay anaphase onset when Topo II is perturbed, providing additional time for decatenation. Molecular insight into this checkpoint is lacking. Here we present evidence that catalytic inhibition of Topo II, which activates the checkpoint, leads to SUMOylation of the Topo II C-terminal domain (CTD). This modification triggers mobilization of Aurora B kinase from inner centromeres to kinetochore proximal centromeres and the core of chromosome arms. Aurora B recruitment accompanies histone H3 threonine-3 phosphorylation and requires Haspin kinase. Strikingly, activation of the checkpoint depends both on Haspin and Aurora B. Moreover, mutation of the conserved CTD SUMOylation sites perturbs Aurora B recruitment and checkpoint activation. The data indicate that SUMOylated Topo II recruits Aurora B to ectopic sites, constituting the molecular trigger of the metaphase checkpoint when Topo II is catalytically inhibited.

Gestures Occur With Spatial and Motoric Knowledge: It's More Than Just Coincidence

2015 ◽  
Vol 22 (2) ◽  
pp. 42-49
Author(s):  
Autumn Hostetter ◽  
Elina Mainela-Arnold
Keyword(s):  
Individual Differences ◽  
Cognitive Load ◽  
Speech Production ◽  
Arm Movements ◽  
Semantic Content ◽  
Present Evidence ◽  
Production Processes ◽  
Representational Gestures ◽  
Insight Into ◽  
Gesture Production

Representational gestures are hand and arm movements that are related to the semantic content of co-occurring speech. In this review, we present evidence that such movements not only provide insight into the knowledge possessed by a speaker, but also provide insight into how that knowledge is represented. Specifically, gestures often occur with the communication of information that is understood spatially or motorically but that has not yet been verbally or linguistically encoded. Using gesture to convey such information can have a number of benefits for speakers, including facilitation of speech production processes and reduction of cognitive load. We focus our review on evidence from individual differences in gesture production among both typical and clinical populations, and conclude with a few recommendations for language therapists who are interested in using gesture as a tool in their practice.

scholarly journals Insight into the role of alternative splicing within the RBM10v1 exon 10 tandem donor site

2015 ◽  
Vol 8 (1) ◽  
pp. 46 ◽  
Author(s):  
Sarah J Tessier ◽  
Julie J Loiselle ◽  
Anne McBain ◽  
Celine Pullen ◽  
Benjamin W Koenderink ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Donor Site ◽  
Insight Into ◽  
Exon 10

scholarly journals Ubiquitous Forbidden Order in R-group classified protein sequence of SARS-CoV-2 and other viruses

2020 ◽  
Author(s):  
Pratibha ◽  
C. Shaju ◽  
Kamal
Keyword(s):  
Amino Acids ◽  
Protein Sequence ◽  
Polypeptide Chain ◽  
Random Sequence ◽  
Protein Sequences ◽  
Chemical Behavior ◽  
Coding Sequences ◽  
Linear Sequence ◽  
Novel Method ◽  
Insight Into

AbstractEach amino acid in a polypeptide chain has a distinctive R-group associated with it. We report here a novel method of species characterization based upon the order of these R-group classified amino acids in the linear sequence of the side chains associated with the codon triplets. In an otherwise pseudo-random sequence, we search for forbidden combinations of kth order. We applied this method to analyze the available protein sequences of various viruses including SARS-CoV-2. We found that these ubiquitous forbidden orders (UFO) are unique to each of the viruses we analyzed. This unique structure of the viruses may provide an insight into viruses’ chemical behavior and the folding patterns of the proteins. This finding may have a broad significance for the analysis of coding sequences of species in general.

scholarly journals Origination of Ds Elements From Ac Elements in Maize: Evidence for Rare Repair Synthesis at the Site of Ac Excision

Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1733-1740 ◽  
Author(s):  
Xianghe Yan ◽  
Isabel M Martínez-Férez ◽  
Steven Kavchok ◽  
Hugo K Dooner
Keyword(s):  
De Novo ◽  
Donor Site ◽  
Double Strand Breaks ◽  
Direct Repeats ◽  
End Joining ◽  
Repair Synthesis ◽  
Strand Breaks ◽  
Ac Transposition ◽  
Insight Into ◽  
Deletion Junction

Abstract Although it has been known for some time that the maize transposon Ac can mutate to Ds by undergoing internal deletions, the mechanism by which these mutations arise has remained conjectural. To gain further insight into this mechanism in maize we have studied a series of Ds elements that originated de novo from Ac elements at known locations in the genome. We present evidence that new, internally deleted Ds elements can arise at the Ac donor site when Ac transposes to another site in the genome. However, internal deletions are rare relative to Ac excision footprints, the predominant products of Ac transposition. We have characterized the deletion junctions in five new Ds elements. Short direct repeats of variable length occur adjacent to the deletion junction in three of the five Ds derivatives. In the remaining two, extra sequences or filler DNA is inserted at the junction. The filler DNAs are identical to sequences found close to the junction in the Ac DNA, where they are flanked by the same sequences that flank the filler DNA in the deletion. These findings are explained most simply by a mechanism involving error-prone DNA replication as an occasional alternative to end-joining in the repair of Ac-generated double-strand breaks.

In Vitro Reconstitution of Differentiated Human Epithelia

1992 ◽  
Vol 20 (1) ◽  
pp. 95-102
Author(s):  
Graziella Pellegrini ◽  
Roberto Gherzi ◽  
Adriano Tito Franzi ◽  
Fiorella D'Anna ◽  
Michele De Luca ◽  
...  
Keyword(s):  
Donor Site ◽  
Three Dimensional ◽  
Basal Layer ◽  
Human Keratinocytes ◽  
Culture Conditions ◽  
3T3 Fibroblasts ◽  
Stratified Squamous Epithelium ◽  
Original Donor

Human keratinocytes obtained from skin biopsies can be serially cultured in vitro. When plated on lethally irradiated 3T3 fibroblasts, keratinocyte colonies reconstitute a stratified squamous epithelium devoid of stratum corneum. The expression of a mature cornified epidermis, expressing all the morphological and biochemical markers of the in vivo epidermis, can be obtained by the “emerged dermal equivalent” culture system. Melanocytes grown under the same culture conditions, maintain a physiological melanocyte/keratinocyte ratio, are organised in the basal layer of the cultured epidermis, and maintain differentiated functions such as dendritic arborisation, melanin synthesis and melanosome transfer. This allows the reconstitution of an epidermis physiologically populated by functionally active melanocytes. Epithelial cells from different mucosal body sites, namely palate, urethra, conjunctiva, cornea and vagina, can also be cultured and maintain the characteristics of the original donor sites. The in vitro reconstituted human epithelia, permanently transplanted onto patients presenting large epidermal or mucosal defects, retain the characteristics of the original donor site, suggesting an intrinsic site-specific differentiation programme. These three-dimensional human epithelium models could prove useful in standard cytotoxicity assays and could be used as a tool to study the effects of a variety of compounds on normal human epithelia in vitro.

Calibration problems in hydrogen luminosities

1966 ◽  
Vol 24 ◽  
pp. 322-330
Author(s):  
A. Beer
Keyword(s):  
Galactic Structure ◽  
B Stars ◽  
Insight Into

The investigations which I should like to summarize in this paper concern recent photo-electric luminosity determinations of O and B stars. Their final aim has been the derivation of new stellar distances, and some insight into certain patterns of galactic structure.

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