Phase Shifts of the Triplet Periodicity in DNA Sequences of Genes

Author(s):  
Е.В. Коротков ◽  
E.V. Korotkov
Author(s):  
В.А. Кутыркин ◽  
V.A. Kutyrkin

Structural-statistical characteristics of the coding DNA sequences (CDSs) from human genome are investigated in the frame of spectral-statistical approach (the 2S-approach). Properties of 3-regularity and latent profile periodicity are among of such the characteristics. Special meaning and intrinsic existence of these properties are confirmed by researching the binary recoded CDSs. The only one kind of singular recoding, that identifies complementary nucleotides, serves to persistence of the original CDSs characteristics. Usage of nonsingular binary recoding proves a statement that latent triplet periodicity in the CDSs of human genome belongs to earlier unknown type called as profile periodicity.


1985 ◽  
Vol 40 (11-12) ◽  
pp. 854-857
Author(s):  
N. Burr Furlong ◽  
Koenraad Marien

Abstract There are non-random features in the occurrences of nucleotides in the DNA’s of certain organisms which are detectable by statistical analyses of the entire sequence. Earlier, using the bacteriophage Phi-X 174 DNA sequence, we had reported that the self-information values for one type of dinucleotide association showed a marked periodicity when their autocorrelation coefficients were graphed. A similar, but computationally simpler, analysis has been developed which gives a comparable indication of periodicity. The difference, in average autocorrelation coefficients obtained with this analysis, between the peak values and all others has been used as an index to compare the extent of periodic non-randomness for a series of natural DNA sequences and for various artificial sequences. Calculations show that triplet periodicity, the relationship between dinucleotides separated by a single nucleotide, is characteristic only of the natural sequences of certain filamentous phages and is not found prominently in any other DNA analyzed (including sequences of similar length from plasmids, yeast, bacteria and higher animals). By shuffling nucleotides in a given sequence or by substituting selected nucleotides to alter various positions in both periodic and aperiodic sequences, we have found that an excess or deficiency of a given nucleotide at one of the three positions in a triplet reading frame can simulate the periodic characteristic. Thus, it appears that this global statistical analysis detects the tendency for single­ strand phages to utilize a specific nucleotide, rather than one randomly selected, to constitute codons.


2010 ◽  
Vol 7 (3) ◽  
pp. 219-230 ◽  
Author(s):  
Eugene V. Korotkov ◽  
Maria A. Korotkova

Abstract The definition of a phase shift of triplet periodicity (TP) is introduced. The mathematical algorithm for detection of TP phase shift of nucleotide sequences has been developed. Gene sequences from Kegg-46 data bank were analyzed with a purpose of searching genes with a phase shift of TP. The presence of a phase shift of triplet periodicity has been shown for 318329 genes (~10% from the number of genes in Kegg-46). We suppose that shifts of the TP phase may indicate the shifts of reading frame (RF) in genes. A relationship between the phase shifts of TP and the frame shifts in genes is discussed.


Author(s):  
David P. Bazett-Jones ◽  
Mark L. Brown

A multisubunit RNA polymerase enzyme is ultimately responsible for transcription initiation and elongation of RNA, but recognition of the proper start site by the enzyme is regulated by general, temporal and gene-specific trans-factors interacting at promoter and enhancer DNA sequences. To understand the molecular mechanisms which precisely regulate the transcription initiation event, it is crucial to elucidate the structure of the transcription factor/DNA complexes involved. Electron spectroscopic imaging (ESI) provides the opportunity to visualize individual DNA molecules. Enhancement of DNA contrast with ESI is accomplished by imaging with electrons that have interacted with inner shell electrons of phosphorus in the DNA backbone. Phosphorus detection at this intermediately high level of resolution (≈lnm) permits selective imaging of the DNA, to determine whether the protein factors compact, bend or wrap the DNA. Simultaneously, mass analysis and phosphorus content can be measured quantitatively, using adjacent DNA or tobacco mosaic virus (TMV) as mass and phosphorus standards. These two parameters provide stoichiometric information relating the ratios of protein:DNA content.


Author(s):  
Barbara Trask ◽  
Susan Allen ◽  
Anne Bergmann ◽  
Mari Christensen ◽  
Anne Fertitta ◽  
...  

Using fluorescence in situ hybridization (FISH), the positions of DNA sequences can be discretely marked with a fluorescent spot. The efficiency of marking DNA sequences of the size cloned in cosmids is 90-95%, and the fluorescent spots produced after FISH are ≈0.3 μm in diameter. Sites of two sequences can be distinguished using two-color FISH. Different reporter molecules, such as biotin or digoxigenin, are incorporated into DNA sequence probes by nick translation. These reporter molecules are labeled after hybridization with different fluorochromes, e.g., FITC and Texas Red. The development of dual band pass filters (Chromatechnology) allows these fluorochromes to be photographed simultaneously without registration shift.


Author(s):  
José L. Carrascosa ◽  
José M. Valpuesta ◽  
Hisao Fujisawa

The head to tail connector of bacteriophages plays a fundamental role in the assembly of viral heads and DNA packaging. In spite of the absence of sequence homology, the structure of connectors from different viruses (T4, Ø29, T3, P22, etc) share common morphological features, that are most clearly revealed in their three-dimensional structure. We have studied the three-dimensional reconstruction of the connector protein from phage T3 (gp 8) from tilted view of two dimensional crystals obtained from this protein after cloning and purification.DNA sequences including gene 8 from phage T3 were cloned, into Bam Hl-Eco Rl sites down stream of lambda promotor PL, in the expression vector pNT45 under the control of cI857. E R204 (pNT89) cells were incubated at 42°C for 2h, harvested and resuspended in 20 mM Tris HC1 (pH 7.4), 7mM 2 mercaptoethanol, ImM EDTA. The cells were lysed by freezing and thawing in the presence of lysozyme (lmg/ml) and ligthly sonicated. The low speed supernatant was precipitated by ammonium sulfate (60% saturated) and dissolved in the original buffer to be subjected to gel nitration through Sepharose 6B, followed by phosphocellulose colum (Pll) and DEAE cellulose colum (DE52). Purified gp8 appeared at 0.3M NaCl and formed crystals when its concentration increased above 1.5 mg/ml.


2019 ◽  
Vol 63 (6) ◽  
pp. 757-771 ◽  
Author(s):  
Claire Francastel ◽  
Frédérique Magdinier

Abstract Despite the tremendous progress made in recent years in assembling the human genome, tandemly repeated DNA elements remain poorly characterized. These sequences account for the vast majority of methylated sites in the human genome and their methylated state is necessary for this repetitive DNA to function properly and to maintain genome integrity. Furthermore, recent advances highlight the emerging role of these sequences in regulating the functions of the human genome and its variability during evolution, among individuals, or in disease susceptibility. In addition, a number of inherited rare diseases are directly linked to the alteration of some of these repetitive DNA sequences, either through changes in the organization or size of the tandem repeat arrays or through mutations in genes encoding chromatin modifiers involved in the epigenetic regulation of these elements. Although largely overlooked so far in the functional annotation of the human genome, satellite elements play key roles in its architectural and topological organization. This includes functions as boundary elements delimitating functional domains or assembly of repressive nuclear compartments, with local or distal impact on gene expression. Thus, the consideration of satellite repeats organization and their associated epigenetic landmarks, including DNA methylation (DNAme), will become unavoidable in the near future to fully decipher human phenotypes and associated diseases.


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