Expression of Transposable Elements throughout the Trematode Life Cycle.

Background: Transposable elements (TEs) are major components of eukaryotic genomes. The extensive body of evidence suggests that although they were once considered "genomic parasites", transposons and their transcripts perform specific functions, such as regulation of early embryo development. Understanding the role of TEs in such parasites as trematodes is becoming critically important.

Tandem Repeat Diversity in Two Closely Related Hamster Species-The Chinese Hamster () and Striped Hamster ().

The Chinese hamster () and striped hamster () are very closely related species with similar karyotypes. The karyotypes differ from each other by one Robertsonian rearrangement and X-chromosome morphology. The level of the tandem repeat (TR) sequences' evolutional variability is high.

Novel protein from larval sponge cells, ilborin, is related to energy turnover and calcium binding and is conserved among marine invertebrates.

Sponges (phylum Porifera) are early-branching animals, whose outwardly simple body plan is underlain by a complex genetic repertoire. The transition from a mobile larva to an attached filter-feeding organism occurs by metamorphosis, a process accompanied by a radical change of the body plan and cell transdifferentiation. The continuity between larval cells and adult tissues is still obscure.

Transposons-Based Clonal Diversity in Trematode Involves Parts of CR1 (LINE) in Eu- and Heterochromatin.

Trematode parthenitae have long been believed to form clonal populations, but clonal diversity has been discovered in this asexual stage of the lifecycle. Clonal polymorphism in the model species has been previously described, but the source of this phenomenon remains unknown. In this work, we traced cercarial clonal diversity using a simplified amplified fragment length polymorphism (SAFLP) method and characterised the nature of fragments in diverse electrophoretic bands.

The Long Linker Region of Telomere-Binding Protein TRF2 Is Responsible for Interactions with Lamins.

Telomere-binding factor 2 (TRF2) is part of the shelterin protein complex found at chromosome ends. Lamin A/C interacts with TRF2 and influences telomere position. TRF2 has an intrinsically disordered region between the ordered dimerization and DNA-binding domains.

Tandem Repeat-Based Probes Support the Loop Model of Pericentromere Packing.

Constitutive heterochromatin is the most mysterious part of the eukaryotic genome. It forms vital chromosome regions such as the centromeric and the pericentromeric ones. The main component of heterochromatic regions are tandem repeats (TR), and their specific organization complicates assembly, annotation, and mapping of these regions.

Amino acid sequence associated with bacteriophage recombination site helps to reveal genes potentially acquired through horizontal gene transfer.

Background: Horizontal gene transfer, i.e. the acquisition of genetic material from nonparent organism, is considered an important force driving species evolution.

Actin depolymerization disrupts karyosphere capsule integrity but not residual transcription in late oocytes of the grass frog Rana temporaria.

Late diplotene oocytes are characterized by an essential decrease in transcriptional activity. At this time, chromosomes condense and form a compact structure named a karyosphere. The karyosphere of grass frogs Rana temporaria is surrounded by a fibrillar karyosphere capsule (KC).

From traveler to homebody: Which signaling mechanisms sponge larvae use to become adult sponges?

Cell-to-cell signaling is responsible for regulation of many developmental processes such as proliferation, cell migration, survival, cell fate specification and axis patterning. In this article we discussed the role of signaling in the metamorphosis of sponges with a focus on epithelial-mesenchymal transition (EMT) accompanying this event. Sponges (Porifera) are an ancient lineage of morphologically simple animals occupying a basal position on the tree of life.

Features of a novel protein, rusticalin, from the ascidian reveal ancestral horizontal gene transfer event.

Background: The transfer of genetic material from non-parent organisms is called horizontal gene transfer (HGT). One of the most conclusive cases of HGT in metazoans was previously described for the cellulose synthase gene in ascidians.

Results: In this study we identified a new protein, rusticalin, from the ascidian and presented evidence for its likely origin by HGT.

The karyosphere capsule in Rana temporaria oocytes contains structural and DNA-binding proteins.

During the last stages of oogenesis, oocyte chromosomes condense and come close together, forming the so-called karyosphere. Karyosphere formation is accompanied by an essential decrease in transcriptional activity. In the grass frog Rana temporaria, the karyosphere is surrounded by an extrachromosomal capsule that separates the chromosomes from the rest of the nucleoplasm.

Mouse chromocenters DNA content: sequencing and in silico analysis.

Background: Chromocenters are defined as a punctate condensed blocks of chromatin in the interphase cell nuclei of certain cell types with unknown biological significance. In recent years a progress in revealing of chromocenters protein content has been made although the details of DNA content within constitutive heterochromatin still remain unclear. It is known that these regions are enriched in tandem repeats (TR) and transposable elements.

The exon junction complex factor Y14 is dynamic in the nucleus of the beetle during late oogenesis.

Background: The oocyte chromosomes of the red flour beetle, , are gathered into a knot, forming a karyosphere at the diplotene stage of meiotic prophase. Chromatin rearrangement, which is a characteristic feature of oocyte maturation, is well documented. The karyosphere is surrounded by a complex extrachromosomal structure termed the karyosphere capsule.

Heterochromatic Tandem Repeats in the Extracellular DNA.

Only limited sequencing data of the normal extracellular DNA (ecDNA) are currently available. The uptake of the ecDNA by cultured cells and its integration into the host chromatin have been demonstrated. A number of membrane-bearing vesicles in plasma and serum have been shown to carry nucleic acids.

Karyotype features of trematode Himasthla elongata.

Background: Trematodes have a complex life cycle with animal host changes and alternation of parthenogenetic and hermaphrodite generations. The parthenogenetic generation of the worm (rediae) from the first intermediate host Littorina littorea was used for chromosome spreads production. Karyotype description of parasitic flatworm Himasthla elongata Mehlis, 1831 (Digenea: Himasthlidae) based on fluorochrome banding and 18S rDNA mapping.

LINE-related component of mouse heterochromatin and complex chromocenters' composition.

Chromocenters are interphase nuclear landmark structures of constitutive heterochromatin. The tandem repeat (TR)-enriched parts of different chromosomes cluster together in chromocenters. There has been progress in recent years in determining the protein content of chromocenters, although it is not clear which DNA sequences underly constitutive heterochromatin apart from the TRs.

Telomere Repeat-Binding Factor 2 Is Responsible for the Telomere Attachment to the Nuclear Membrane.

Telomeres are nucleoprotein structures that specify ends of eukaryotic chromosomes. They enable complete DNA replication, protect chromosomes from end-to-end fusions, and help organize chromatin structure. These functions are mediated by special telomeric proteins.

Large tandem repeats make up the chromosome bar code: a hypothesis.

Much of tandem repeats' functional nature in any genome remains enigmatic because there are only few tools available for dissecting and elucidating the functions of repeated DNA. The large tandem repeat arrays (satellite DNA) found in two mouse whole-genome shotgun assemblies were classified into 4 superfamilies, 8 families, and 62 subfamilies. With the simplified variant of chromosome positioning of different tandem repeats, we noticed the nonuniform distribution instead of the positions reported for mouse major and minor satellites.

Aurelia aurita (Cnidaria) oocytes' contact plate structure and development.

One of the A. aurita medusa main mesoglea polypeptides, mesoglein, has been described previously. Mesoglein belongs to ZP-domain protein family and therefore we focused on A.

Aurelia aurita-Cnidarian with a prominent medusiod stage.

Aurelia aurita has a complex life cycle that consists of several stages including alternating generations of medusa and polyps, huge sexual, and tiny asexual stages. Cnidarian is thought to possess two tissue layers: endoderm (gastroderm) and ectoderm, which are separated by mesoglea in medusa. The determination of the composition of the A.

Tandemly repeated DNA families in the mouse genome.

Background: Functional and morphological studies of tandem DNA repeats, that combine high portion of most genomes, are mostly limited due to the incomplete characterization of these genome elements. We report here a genome wide analysis of the large tandem repeats (TR) found in the mouse genome assemblies.

Results: Using a bioinformatics approach, we identified large TR with array size more than 3 kb in two mouse whole genome shotgun (WGS) assemblies.

The fate of larval flagellated cells during metamorphosis of the sponge Halisarca dujardini.

Sponge larval flagellated cells have been known to form the external layer of larva, but their subsequent fate and morphogenetic role are still unclear. It is actually impossible to follow flagellated cell developmental fate unless a specific marker is found. We used percoll density gradient fractionation to separate different larval cell types of Halisarca dujardini (Demospongiae, Halisarcida).