STUDIES ON THE SAL LOCUS IN DROSOPHILA PSEUDOOBSCURA. III. THE MOLECULAR PATTERN OF DNA IN ACTIVE AND INACTIVE CHROMOSOME REGIONS

1973 ◽  
Vol 15 (3) ◽  
pp. 497-507 ◽  
Author(s):  
Eileen Sutton Gersh
Keyword(s):  
Double Helix ◽  
Drosophila Pseudoobscura ◽  
Chromosome 3 ◽  
Gene Products ◽  
Position Effects ◽  
Molecular Pattern ◽  
Cytological Changes ◽  
Dna Double Helix ◽  
Osmotic Effects ◽  
Chromosome Regions

The banding pattern at the tip of salivary gland chromosome 3 in Drosophila pseudoobscura is determined by a nearby locus, sal (salivary). A number of cytological changes in the neighborhood of the sal locus have been obtained. Their effects on the appearance of bands are interpreted in terms of the fine structure of the chromosome and the arrangement of the DNA double helix. Bands as viewed in the light microscope may become dispersed, as in puffs, or compacted, as in position effects involving their transposition to heterochromatic regions. Changes of bands are interpreted in terms of dispersion or compaction of DNA.Secondary puffing is induced in a paired sal chromosome which does not puff when unpaired, by a sal+ homologue which puffs when unpaired. This is explained as being due to osmotic effects caused by added protein and gene products (RNAs) diffusing from the sal+ to the sal chromosome, when they are paired, through submicroscopic interconnecting spaces within the chromosomes.

scholarly journals Holding All the Cards—How Fanconi Anemia Proteins Deal with Replication Stress and Preserve Genomic Stability

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 170 ◽  
Author(s):  
Arindam Datta ◽  
Robert M. Brosh Jr.
Keyword(s):  
Dna Damage ◽  
Fanconi Anemia ◽  
Excision Repair ◽  
Double Helix ◽  
Bone Marrow Failure ◽  
Molecular Genetic ◽  
Replication Stress ◽  
Gene Products ◽  
Hematopoietic Stem ◽  
Dna Double Helix

Fanconi anemia (FA) is a hereditary chromosomal instability disorder often displaying congenital abnormalities and characterized by a predisposition to progressive bone marrow failure (BMF) and cancer. Over the last 25 years since the discovery of the first linkage of genetic mutations to FA, its molecular genetic landscape has expanded tremendously as it became apparent that FA is a disease characterized by a defect in a specific DNA repair pathway responsible for the correction of covalent cross-links between the two complementary strands of the DNA double helix. This pathway has become increasingly complex, with the discovery of now over 20 FA-linked genes implicated in interstrand cross-link (ICL) repair. Moreover, gene products known to be involved in double-strand break (DSB) repair, mismatch repair (MMR), and nucleotide excision repair (NER) play roles in the ICL response and repair of associated DNA damage. While ICL repair is predominantly coupled with DNA replication, it also can occur in non-replicating cells. DNA damage accumulation and hematopoietic stem cell failure are thought to contribute to the increased inflammation and oxidative stress prevalent in FA. Adding to its confounding nature, certain FA gene products are also engaged in the response to replication stress, caused endogenously or by agents other than ICL-inducing drugs. In this review, we discuss the mechanistic aspects of the FA pathway and the molecular defects leading to elevated replication stress believed to underlie the cellular phenotypes and clinical features of FA.

Protamine-DNA interaction

1978 ◽  
Vol 36 (2) ◽  
pp. 200-201
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Small Volume ◽  
Double Helix ◽  
Dna Interaction ◽  
Dark Field ◽  
Sperm Head ◽  
Nuclear Proteins ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dna Double Helix ◽  
Positively Charged

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.

Mercury Electrodes in Nucleic Acid Electrochemistry: Sensitive Analytical Tools and Probes of DNA Structure. A Review

2004 ◽  
Vol 69 (4) ◽  
pp. 715-747 ◽  
Author(s):  
Miroslav Fojta
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Double Helix ◽  
Dna Structure ◽  
Electrochemical Analysis ◽  
Label Free ◽  
Helix Formation ◽  
Mercury Electrodes ◽  
Dna Strand ◽  
Dna Double Helix

This review is devoted to applications of mercury electrodes in the electrochemical analysis of nucleic acids and in studies of DNA structure and interactions. At the mercury electrodes, nucleic acids yield faradaic signals due to redox processes involving adenine, cytosine and guanine residues, and tensammetric signals due to adsorption/desorption of polynucleotide chains at the electrode surface. Some of these signals are highly sensitive to DNA structure, providing information about conformation changes of the DNA double helix, formation of DNA strand breaks as well as covalent or non-covalent DNA interactions with small molecules (including genotoxic agents, drugs, etc.). Measurements at mercury electrodes allow for determination of small quantities of unmodified or electrochemically labeled nucleic acids. DNA-modified mercury electrodes have been used as biodetectors for DNA damaging agents or as detection electrodes in DNA hybridization assays. Mercury film and solid amalgam electrodes possess similar features in the nucleic acid analysis to mercury drop electrodes. On the contrary, intrinsic (label-free) DNA electrochemical responses at other (non-mercury) solid electrodes cannot provide information about small changes of the DNA structure. A review with 188 references.

scholarly journals The molecular structure of the left-handed Z-DNA double helix at 1.0-Å atomic resolution

1989 ◽  
Vol 264 (14) ◽  
pp. 7921-7935
Author(s):  
R V Gessner ◽  
C A Frederick ◽  
G J Quigley ◽  
A Rich ◽  
A H J Wang
Keyword(s):  
Molecular Structure ◽  
Double Helix ◽  
Atomic Resolution ◽  
Left Handed ◽  
Z Dna ◽  
Dna Double Helix
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