scholarly journals Islands of complex DNA are widespread in Drosophila centric heterochromatin.

Genetics ◽  
1995 ◽  
Vol 141 (1) ◽  
pp. 283-303
Author(s):  
M H Le ◽  
D Duricka ◽  
G H Karpen
Keyword(s):  
Dna Sequences ◽  
Structure And Function ◽  
Southern Analysis ◽  
Cloning And Sequencing ◽  
Pulsed Field ◽  
Drosophila Heterochromatin ◽  
And Function ◽  
Heterochromatin Structure ◽  
Derivatives Of ◽  
Eukaryotic Genomes

Abstract Heterochromatin is a ubiquitous yet poorly understood component of multicellular eukaryotic genomes. Major gaps exist in our knowledge of the nature and overall organization of DNA sequences present in heterochromatin. We have investigated the molecular structure of the 1 Mb of centric heterochromatin in the Drosophila minichromosome Dp1187. A genetic screen of irradiated minichromosomes yielded rearranged derivatives of Dp1187 whose structures were determined by pulsed-field Southern analysis and PCR. Three Dp1187 deletion derivatives and an inversion had one breakpoint in the euchromatin and one in the heterochromatin, providing direct molecular access to previously inaccessible parts of the heterochromatin. End-probed pulsed-field restriction mapping revealed the presence of at least three "islands" of complex DNA, Tahiti, Moorea, and Bora Bora, constituting approximately one half of the Dp1187 heterochromatin. Pulsed-field Southern analysis demonstrated that Drosophila heterochromatin in general is composed of alternating blocks of complex DNA and simple satellite DNA. Cloning and sequencing of a small part of one island, Tahiti, demonstrated the presence of a retroposon. The implications of these findings to heterochromatin structure and function are discussed.

Drosophila heterochromatin: structure and function

2014 ◽  
Vol 1 ◽  
pp. 19-24 ◽  
Author(s):  
Rana Mteirek ◽  
Nathalie Gueguen ◽  
Silke Jensen ◽  
Emilie Brasset ◽  
Chantal Vaury
Keyword(s):  
Structure And Function ◽  
Drosophila Heterochromatin ◽  
And Function ◽  
Heterochromatin Structure

scholarly journals DNAContentViewer a BioJS component to visualise GC/AT Content

F1000Research ◽  
2014 ◽  
Vol 3 ◽  
pp. 54 ◽  
Author(s):  
Anil S. Thanki ◽  
Shabhonam Caim ◽  
Manuel Corpas ◽  
Robert P. Davey
Keyword(s):  
Dna Sequences ◽  
Genome Analysis ◽  
Biological Function ◽  
Structure And Function ◽  
Link Type ◽  
And Function ◽  
Potential Interactions

Summary: Compositional GC/AT content of DNA sequences is a useful feature in genome analysis. GC/AT content provides useful information about evolution, structure and function of genomes, giving clues about their biological function and organisation. We have developed DNAContentViewer, a BioJS component for visualisation of compositional GC/AT content in raw sequences. DNAContentViewer has been integrated in the BioJS project as part of the BioJS registry of components. DNAContentViewer requires a simple configuration and installation. Its design allows potential interactions with other components via predefined events. Availability: http://github.com/biojs/biojs; doi: 10.5281/zenodo.7722.

scholarly journals Chromatin-Mediated Regulation of Genome Plasticity in Human Fungal Pathogens

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 855 ◽  
Author(s):  
Buscaino
Keyword(s):  
Candida Albicans ◽  
Aspergillus Fumigatus ◽  
Cryptococcus Neoformans ◽  
Fungal Pathogens ◽  
Environmental Changes ◽  
Structure And Function ◽  
Model Systems ◽  
Genome Plasticity ◽  
And Function ◽  
Heterochromatin Structure

Human fungal pathogens, such as Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans, are a public health problem, causing millions of infections and killing almost half a million people annually. The ability of these pathogens to colonise almost every organ in the human body and cause life-threating infections relies on their capacity to adapt and thrive in diverse hostile host-niche environments. Stress-induced genome instability is a key adaptive strategy used by human fungal pathogens as it increases genetic diversity, thereby allowing selection of genotype(s) better adapted to a new environment. Heterochromatin represses gene expression and deleterious recombination and could play a key role in modulating genome stability in response to environmental changes. However, very little is known about heterochromatin structure and function in human fungal pathogens. In this review, I use our knowledge of heterochromatin structure and function in fungal model systems as a road map to review the role of heterochromatin in regulating genome plasticity in the most common human fungal pathogens: Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans.

scholarly journals Sequential de novo centromere formation and inactivation on a chromosomal fragment in maize

2015 ◽  
Vol 112 (11) ◽  
pp. E1263-E1271 ◽  
Author(s):  
Yalin Liu ◽  
Handong Su ◽  
Junling Pang ◽  
Zhi Gao ◽  
Xiu-Jie Wang ◽  
...  
Keyword(s):  
Dna Sequences ◽  
De Novo ◽  
B Chromosome ◽  
Chromosome 9 ◽  
Centromeric Dna ◽  
Repeat Sequences ◽  
Centromeric Repeat ◽  
And Function ◽  
Centromere Assembly ◽  
Derivatives Of

The ability of centromeres to alternate between active and inactive states indicates significant epigenetic aspects controlling centromere assembly and function. In maize (Zea mays), misdivision of the B chromosome centromere on a translocation with the short arm of chromosome 9 (TB-9Sb) can produce many variants with varying centromere sizes and centromeric DNA sequences. In such derivatives of TB-9Sb, we found a de novo centromere on chromosome derivative 3-3, which has no canonical centromeric repeat sequences. This centromere is derived from a 288-kb region on the short arm of chromosome 9, and is 19 megabases (Mb) removed from the translocation breakpoint of chromosome 9 in TB-9Sb. The functional B centromere in progenitor telo2-2 is deleted from derivative 3-3, but some B-repeat sequences remain. The de novo centromere of derivative 3-3 becomes inactive in three further derivatives with new centromeres being formed elsewhere on each chromosome. Our results suggest that de novo centromere initiation is quite common and can persist on chromosomal fragments without a canonical centromere. However, we hypothesize that when de novo centromeres are initiated in opposition to a larger normal centromere, they are cleared from the chromosome by inactivation, thus maintaining karyotype integrity.

scholarly journals In situ analyses reveal that the two nuclei of Giardia lamblia are equivalent

1990 ◽  
Vol 95 (3) ◽  
pp. 353-360 ◽  
Author(s):  
K.S. Kabnick ◽  
D.A. Peattie
Keyword(s):  
Ribosomal Dna ◽  
Dna Sequences ◽  
Giardia Lamblia ◽  
Transcriptional Activity ◽  
Protozoan Parasite ◽  
Structure And Function ◽  
Higher Eukaryotes ◽  
And Function

The protozoan parasite Giardia lamblia has the unusual morphology of bearing two equal-sized nuclei. This organism probably represents the earliest diverging lineage of eukaryotes, suggesting that its biological tactics may be transitional. To begin to understand the role played by the two equal-sized nuclei in this organism, and perhaps the role this organism has played along the path to higher eukaryotes, we have analyzed the structure and function of these two nuclei. We show that the two nuclei are equivalent with respect to the amount of DNA harbored in each nucleus, the presence of ribosomal DNA sequences, and the transcriptional activity. We begin also to address the question of how these bilaterally symmetrical ancestors divide, by illustrating the mitotic plane of division.

Genomics, Proteomics, and Metabolomics

2021 ◽  
pp. 328-400
Keyword(s):  
Functional Genomics ◽  
Gene Product ◽  
Structural Genomics ◽  
Dna Sequences ◽  
Structure And Function ◽  
Nucleotide Sequences ◽  
Metabolomics Data ◽  
Practical Utilization ◽  
Basic Concepts ◽  
And Function

Genomics could be viewed as the study of the randomness of DNA sequences. It may be possible to predict the structure of a gene product from the nucleotide sequences and thereby predict its function. The terms “structural genomics” and “functional genomics” were coined to denote the assignment of structure and function to a gene product, respectively. Proteomics focuses on the products of gene, which are basically proteins. Proteins are responsible for the development of phenotype, and proteomics is the bridge between genotype and phenotype. The transcribed mRNAs and their abundance are called transcriptome. Proteomics also deals with the interaction between proteins called intractomics. Metabolomics is concerned with identification, abundance, and localization of all the molecules excluding lipids and polysaccharides in the cell. In this chapter, the basic concepts and analysis of the genomic, proteomic, and metabolomics data for their practical utilization are discussed.

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