Chromatin Diminution in Cyclops kolensis Lill. (Copepoda, Crustacea) as a Radical Way to Inactivate Redundant Genome in Somatic Cells

2018 ◽  
Vol 156 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Andrey K. Grishanin ◽  
Maxim V. Zagoskin
Keyword(s):  
Chromosome Number ◽  
Repetitive Sequences ◽  
Early Embryogenesis ◽  
Chromosome Size ◽  
Chromatin Diminution ◽  
Elimination Process ◽  
Dna Elimination ◽  
Molecular Studies ◽  
Cyclops Kolensis

Chromatin diminution (CD) is a phenomenon of programmed DNA elimination which takes place in early embryogenesis in some eukaryotes. The mechanism and biological role of CD remain largely unknown. During CD in the freshwater copepod Cyclops kolensis, the genome of cells of the somatic lineage is reorganized and reduced in size by more than 90% without affecting the genome of germline cells. Although the diploid chromosome number is unchanged, chromosome size is dramatically reduced by CD. The eliminated DNA consists primarily of repetitive sequences and localizes within granules during the elimination process. In this review, we provide an overview of CD in C. kolensis including both cytological and molecular studies.

Chromatin diminution in the copepod Mesocyclops edax: elimination of both highly repetitive and nonhighly repetitive DNA

Genome ◽  
2013 ◽  
Vol 56 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Christian McKinnon ◽  
Guy Drouin
Keyword(s):  
Repetitive Dna ◽  
Tandem Repeats ◽  
Repetitive Sequences ◽  
Embryonic Cells ◽  
Chromatin Diminution ◽  
Developmentally Regulated ◽  
Dna Elimination ◽  
Eukaryotic Species ◽  
Cyclops Kolensis ◽  
Mesocyclops Edax

Chromatin diminution, a developmentally regulated process of DNA elimination, is found in numerous eukaryotic species. In the copepod Mesocyclops edax, some 90% of its genomic DNA is eliminated during the differentiation of embryonic cells into somatic cells. Previous studies have shown that the eliminated DNA contains highly repetitive sequences. Here, we sequenced DNA fragments from pre- and postdiminution cells to determine whether nonhighly repetitive sequences are also eliminated during the process of chromatin diminution. Comparative analyses of these sequences, as well as the sequences eliminated from the genome of the copepod Cyclops kolensis, show that they all share similar abundances of tandem repeats, dispersed repeats, transposable elements, and various coding and noncoding sequences. This suggests that, in the chromatin diminution observed in M. edax, both highly repetitive and nonhighly repetitive sequences are eliminated and that there is no bias in the type of nonhighly repetitive DNA being eliminated.

Role of Auxin in Early Embryogenesis of Plants

2014 ◽  
Vol 48 (4) ◽  
pp. 371-380
Author(s):  
Song Lizhen ◽  
Wang Yi ◽  
Yang Qinghua ◽  
Cheng Youfa
Keyword(s):  
Early Embryogenesis

On the role of germ cells in planarian regeneration

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 53-63
Author(s):  
V. Gremigni ◽  
C. Miceli ◽  
I. Puccinelli
Keyword(s):  
Chromosome Number ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Karyological Analysis ◽  
Blastema Formation ◽  
Planarian Regeneration ◽  
Somatic Tissues ◽  
Caudal Area ◽  
Complete Regeneration

Specimens from a polyploid biotype of Dugesia lugubris s.l. were used to clarify the role and fate of germ cells during planarian regeneration. These specimens provide a useful karyological marker because embryonic and somatic cells (3n = 12) can be easily distinguished from male (2n = 8) and female (6n = 24) germ cells by their chromosome number. We succeed in demonstrating how primordial germ cells participate in blastema formation and take part in rebuilding somatic tissues. This evidence was obtained by cutting each planarian specimen twice at appropriate levels. The first aimed to induce primordial germ cells to migrate to the wound. The second cut was performed after complete regeneration and aimed to obtain a blastema from a cephalic or caudal area devoid of gonads. A karyological analysis of mitotic cells present in each blastema obtained after the second cut provided evidence that cells, originally belonging to the germ lines, are still present in somatic tissues even months after complete regeneration. The role of primordial germ cells in planarian regeneration was finally discussed in relation to the phenomenon of metaplasia or transdifferentiation.

The role of neurohumours in early embryogenesis

Development ◽  
1970 ◽  
Vol 23 (3) ◽  
pp. 549-569
Author(s):  
G. A. Buznikov ◽  
A. N. Kost ◽  
N. F. Kucherova ◽  
A. L. Mndzhoyan ◽  
N. N. Suvorov ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Functional Activity ◽  
Early Onset ◽  
Active Sites ◽  
Physiological Effect ◽  
Early Embryogenesis ◽  
Dopamine Synthesis ◽  
Direct Involvement ◽  
Misgurnus Fossilis

In previous papers (Buznikov, Chudakova & Zvezdina, 1964; Buznikov, Chudakova, Berdysheva & Vyazmina, 1968) we reported that fertilized eggs of the sea-urchin Strongylocentrotus dröbachiensis synthesized a number of neurohumours, such as serotonin (5-hydroxytryptamine, 5-HT), acetylcholine (ACh), adrenalin (A), noradrenalin (NA) and dopamine. Synthesis of 5-HT was also demonstrated in the fertilized eggs of the loach Misgurnus fossilis and some marine Invertebrata. In experiments with sea-urchin embryos we were able to trace regular changes in the level of 5-HT, ACh, A and NA, related to the first cleavage divisions. This early onset of neurohumour synthesis, as well as regular changes in their level, suggests their direct involvement in the regulation of the first cleavage divisions. The functional activity of neurohumours (M) in adult organisms is realized through their reaction with the active sites of corresponding receptors (R) according to the following equation:The magnitude of the physiological effect under certain conditions is linearly proportional to the number of complexes MR formed (Turpayev, 1962; Ariëns, 1964).

Breakpoint junctions of chromosome 9p deletions in two human glioma cell lines

1994 ◽  
Vol 14 (11) ◽  
pp. 7604-7610
Author(s):  
H M Pomykala ◽  
S K Bohlander ◽  
P L Broeker ◽  
O I Olopade ◽  
M O Díaz
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Repetitive Sequences ◽  
Leukemia Cell ◽  
Chromosome 9 ◽  
Breakpoint Junction ◽  
Leukemia Cell Lines ◽  
Long Interspersed Nuclear Elements

Interstitial deletions of the short arm of chromosome 9 are associated with glioma, acute lymphoblastic leukemia, melanoma, mesothelioma, lung cancer, and bladder cancer. The distal breakpoints of the deletions (in relation to the centromere) in 14 glioma and leukemia cell lines have been mapped within the 400 kb IFN gene cluster located at band 9p21. To obtain information about the mechanism of these deletions, we have isolated and analyzed the nucleotide sequences at the breakpoint junctions in two glioma-derived cell lines. The A1235 cell line has a complex rearrangement of chromosome 9, including a deletion and an inversion that results in two breakpoint junctions. Both breakpoints of the distal inversion junction occurred within AT-rich regions. In the A172 cell line, a tandem heptamer repeat was found on either side of the deletion breakpoint junction. The distal breakpoint occurred 5' of IFNA2; the 256 bp sequenced from the proximal side of the breakpoint revealed 95% homology to long interspersed nuclear elements. One- and two-base-pair overlaps were observed at these junctions. The possible role of sequence overlaps, and repetitive sequences, in the rearrangement is discussed.

scholarly journals FOXP2 exhibits projection neuron class specific expression, but is not required for multiple aspects of cortical histogenesis

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Ryan J Kast ◽  
Alexandra L Lanjewar ◽  
Colton D Smith ◽  
Pat Levitt
Keyword(s):  
Expression Patterns ◽  
Projection Neuron ◽  
Specific Expression ◽  
Neuron Populations ◽  
Mouse Cortex ◽  
Molecular Studies ◽  
Multiple Species ◽  
Molecular Phenotypes ◽  
And Function

The expression patterns of the transcription factor FOXP2 in the developing mammalian forebrain have been described, and some studies have tested the role of this protein in the development and function of specific forebrain circuits by diverse methods and in multiple species. Clinically, mutations in FOXP2 are associated with severe developmental speech disturbances, and molecular studies indicate that impairment of Foxp2 may lead to dysregulation of genes involved in forebrain histogenesis. Here, anatomical and molecular phenotypes of the cortical neuron populations that express FOXP2 were characterized in mice. Additionally, Foxp2 was removed from the developing mouse cortex at different prenatal ages using two Cre-recombinase driver lines. Detailed molecular and circuit analyses were undertaken to identify potential disruptions of development. Surprisingly, the results demonstrate that Foxp2 function is not required for many functions that it has been proposed to regulate, and therefore plays a more limited role in cortical development than previously thought.

ROLE OF THE OVIDUCT DURING EARLY EMBRYOGENESIS

1993 ◽  
Vol 28 (3) ◽  
pp. 189-192 ◽  
Author(s):  
F. Gandolfi ◽  
T. A. L. Brevini ◽  
S. Modina ◽  
R. Bianchi ◽  
L. Passoni
Keyword(s):  
Early Embryogenesis

scholarly journals The granuloma in cryptococcal disease

2021 ◽  
Vol 17 (3) ◽  
pp. e1009342
Author(s):  
Laura C. Ristow ◽  
J. Muse Davis
Keyword(s):  
Granulomatous Inflammation ◽  
Granuloma Formation ◽  
Current Understanding ◽  
Mass Lesion ◽  
Disease Entity ◽  
Major Barrier ◽  
Cryptococcal Disease ◽  
Molecular Studies

Although we have recognized cryptococcosis as a disease entity for well over 100 years, there are many details about its pathogenesis which remain unknown. A major barrier to better understanding is the very broad range of clinical and pathological forms cryptococcal infections can take. One such form has been historically called the cryptococcal granuloma, or the cryptococcoma. These words have been used to describe essentially any mass lesion associated with infection, due to their presumed similarity to the quintessential granuloma, the tubercle in tuberculosis. Although clear distinctions between tuberculosis and cryptococcal disease have been discovered, cellular and molecular studies still confirm some important parallels between these 2 diseases and what we now call granulomatous inflammation. In this review, we shall sketch out some of the history behind the term “granuloma” as it pertains to cryptococcal disease, explore our current understanding of the biology of granuloma formation, and try to place that understanding in the context of the myriad pathological presentations of this infection. Finally, we shall summarize the role of the granuloma in cryptococcal latency and present opportunities for future investigations.

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