Changes in the nuclear polyamine content of chick erythrocytes during embryonic development.
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ABSTRACT:
SUBMITTER: Goyns MH
PROVIDER: S-EPMC1161844 | biostudies-other | 1979 Dec
REPOSITORIES: biostudies-other
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Project description:The two major vertebrate galactosyltransferases have been investigated in developing chick muscle in ovo and in vitro, and in cultured chick fibroblasts. The two enzymes were UDP-galactose-N-acetylglucosamine galactosyltransferase (galactosyltransferase I) and UDP-galactose-N-acetylgalactosamine galactosyltransferase (galactosyltransferase II). Both activities fell during muscle development in ovo. Galactosyltransferase I activity was constant from day 7 to day 16, after which it declined 5-fold, whereas galactosyltransferase II activity fell markedly from day 9 to 13 and 16 to 20, displaying an overall 8-fold decrease. In primary muscle cultures, galactosyltransferase I activity fell slightly during 7 days in culture, whereas galactosyltransferase II increased 2-fold during the same period. No significant change in activity of either galactosyltransferase was observed during intercellular recognition and fusion. Analysis of muscle cultures treated with cytosine arabinoside and of fibroblast cultures revealed that the majority of galactosyltransferase I activity in primary muscle cultures is associated with fibroblasts, whereas the majority of galactosyltransferase II activity is muscle-associated. The addition of 5-bromodeoxyuridine to primary muscle cultures resulted in a 3-fold rise in activities of both transferases.
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Project description:1. Two populations of morphologically intact mitochondria were isolated from embryonic, neonatal and adult chick liver by isopycnic centrifugation. 2. The protein/phospholipid ratio of the total mitochondrial fraction, the low-density mitochondria (B2, d1.176) and the high-density mitochondria (B3, d1.206) did not differ significantly. 3. During development there is a marked increase in the B2 fraction in relation to the B3 fraction. 4. Cytochrome oxidase and malate dehydrogenase activities as well as respiratory control increased during the embryonic development of the chick, though their rates of increase were not correlated. 5. In the three different embryonic stages that were investigated, as well as in the neonatal and adult chick, the protein/lipid as well as the protein/phospholipid ratio stayed constant and showed no progressive increase, as had been previously reported. 6. It was shown that forces greater than 18400g(av.) for 2h have to be used before chick liver mitochondria reach isopycnic equilibrium. 7. As for rat liver mitochondria, the constant protein/phospholipid ratio of the B2 and B3 fractions and their apparent morphological intactness leads one to conclude that the matrix space of B2 mitochondria is inaccessible to sucrose, whereas B3 mitochondria possess an inner membrane that is permeable to sucrose.
| S-EPMC1176965 | biostudies-other
Project description:A recent study from our lab revealed that the inhibition of cyclooxygenase-2 (COX-2) exclusively reduces the level of PGE2 (Prostaglandin E2) among prostanoids and hampers the normal development of several structures, strikingly the cranial vault, in chick embryos. In order to unearth the mechanism behind the deviant development of cranial features, the expression pattern of various factors that are known to influence cranial neural crest cell (CNCC) migration was checked in chick embryos after inhibiting COX-2 activity using etoricoxib. The compromised level of cell adhesion molecules and their upstream regulators, namely CDH1 (E-cadherin), CDH2 (N-cadherin), MSX1 (Msh homeobox 1), and TGF-β (Transforming growth factor beta), observed in the etoricoxib-treated embryos indicate that COX-2, through its downstream effector PGE2, regulates the expression of these factors perhaps to aid the migration of CNCCs. The histological features and levels of FoxD3 (Forkhead box D3), as well as PCNA (Proliferating cell nuclear antigen), further consolidate the role of COX-2 in the migration and survival of CNCCs in developing embryos. The results of the current study indicate that COX-2 plays a pivotal role in orchestrating craniofacial structures perhaps by modulating CNCC proliferation and migration during the embryonic development of chicks.
| S-EPMC8167724 | biostudies-literature
Project description:In mice, genome-wide DNA methylation is actively erased at the onset of fertilisation, followed by remethylation in epiblasts after implantation, leading to inactive chromatin formation as a preliminary step to somatic cell differentiation, and then demethylation again during primitive streak formation and the determination of primordial germ cells (PGCs). This sequence of DNA methylation changes is accompanied by dynamic epigenetic reprogramming, including nuclear structure, histone modification, and intranuclear re-localisation of chromosomes, during totipotency acquisition of the fertilised egg and germline development. Here we show that in the avian strain White Leghorn of Gallus gallus domesticus, global reprogramming of DNA methylation and histone modifications, as seen in mice, is induced during primitive streak formation but then reaches an almost basal state in somatic cells during later embryogenesis unlike mice. Avian chromosomes are subdivided into large and genetically less functioning macrochromosomes (MACs) and gene-rich microchromosomes (MICs), of which remarkable karyotypic composition is evolutionarily conserved from cartilaginous fish to reptiles. We found that these MACs undergo reprogramming that involves particularly active DNA demethylation and removal of trimethylation at lysine 9 of histone H3, leading to activation of the MAC-linked HOXA and HOXD gene clusters that control morphogenesis. We show here that the erasure of genome-wide epigenetics may not only have an important function to initiate differentiation into three germ layers via primitive streak formation, as seen in mice but may also provide a basis for the acquisition of new epigenetics required to regulate morphogenesis during late chicken embryonic development.
2024-10-01 | GSE242250 | GEO
Project description:BACKGROUND: Embryonic development proceeds through finely tuned reprogramming of the parental genomes to form a totipotent embryo. Cells within this embryo will then differentiate and give rise to all the tissues of a new individual. Early embryonic development thus offers a particularly interesting system in which to analyze functional nuclear organization. When the organization of higher-order chromatin structures, such as pericentromeric heterochromatin, was first analyzed in mouse embryos, specific nuclear rearrangements were observed that correlated with embryonic genome activation at the 2-cell stage. However, most existing analyses have been conducted by visual observation of fluorescent images, in two dimensions or on z-stack sections/projections, but only rarely in three dimensions (3D). RESULTS: In the present study, we used DNA fluorescent in situ hybridization (FISH) to localize centromeric (minor satellites), pericentromeric (major satellites), and telomeric genomic sequences throughout the preimplantation period in naturally fertilized mouse embryos (from the 1-cell to blastocyst stage). Their distribution was then analyzed in 3D on confocal image stacks, focusing on the nucleolar precursor bodies and nucleoli known to evolve rapidly throughout the first developmental stages. We used computational imaging to quantify various nuclear parameters in the 3D-FISH images, to analyze the organization of compartments of interest, and to measure physical distances between these compartments. CONCLUSIONS: The results highlight differences in nuclear organization between the two parental inherited genomes at the 1-cell stage, i.e. just after fertilization. We also found that the reprogramming of the embryonic genome, which starts at the 2-cell stage, undergoes other remarkable changes during preimplantation development, particularly at the 4-cell stage.
| S-EPMC3517311 | biostudies-other
Project description:Background:Acquisition of pluripotency by transcriptional regulatory factors is an initial developmental event that is required for regulation of cell fate and lineage specification during early embryonic development. The evolutionarily conserved core transcriptional factors regulating the pluripotency network in fishes, amphibians, and mammals have been elucidated. There are also species-specific maternally inherited transcriptional factors and their intricate transcriptional networks important in the acquisition of pluripotency. In avian species, however, the core transcriptional network that governs the acquisition of pluripotency during early embryonic development is not well understood. Results:We found that chicken NANOG (cNANOG) was expressed in the stages between the pre-ovulatory follicle and oocyte and was continuously detected in Eyal-Giladi and Kochav stage I (EGK.I) to X. However, cPOUV was not expressed during folliculogenesis, but began to be detectable between EGK.V and VI. Unexpectedly, cSOX2 could not be detected during folliculogenesis and intrauterine embryonic development. Instead of cSOX2, cSOX3 was maternally inherited and continuously expressed during chicken intrauterine development. In addition, we found that the pluripotency-related genes such as cENS-1, cKIT, cLIN28A, cMYC, cPRDM14, and cSALL4 began to be dramatically upregulated between EGK.VI and VIII. Conclusion:These results suggest that chickens have a unique pluripotent circuitry since maternally inherited cNANOG and cSOX3 may play an important role in the initial acquisition of pluripotency. Moreover, the acquisition of pluripotency in chicken embryos occurs at around EGK.VI to VIII.
| S-EPMC5891889 | biostudies-literature
Project description:By RT-PCR, we isolated a partial cDNA clone for the chick Semaphorin7A (Sema7A) gene. We further analyzed its expression patterns and compared them with those of the Sema3D gene, in chick embryonic development. Sema3D and Sema7A appeared to be expressed in distinct cell populations. In mesoderm-derived structures, Sema7A expression was detected in the newly formed somites, whereas Sema3D expression was found in the notochord. In ectoderm-derived tissues, Sema3D is expressed broadly in the surface ectoderm, lens and nasal placodes. Sema3D is also expressed in the developing nervous system including diencephalon, dorsal neural tube, optical and otic vesicles. In the limb bud, Sema3D expression was found throughout the ectoderm excluding the apical ectoderm ridge (AER), where Sema7A is concentrated. Although both genes appeared to be expressed in the migrating neural crest cells, Sema3D expression is limited to neural crest cells migrating out of the midbrain/hindbrain regions, while Sema7A expression is widespread in both cranial and trunk neural crest cells.
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Project description:BackgroundSchistosomes cause more mortality and morbidity than any other human helminth, but control primarily relies on a single drug that kills adult worms. The newly transformed schistosomulum stage is susceptible to the immune response and is a target for vaccine development and rational drug design.Methodology/principal findingsTo identify genes which are up-regulated during the maturation of Schistosoma mansoni schistosomula in vitro, we cultured newly transformed parasites for 3 h or 5 days with and without erythrocytes and compared their transcriptional profiles using cDNA microarrays. The most apparent changes were in the up-regulation of genes between 3 h and 5 day schistosomula involved in blood feeding, tegument and cytoskeletal development, cell adhesion, and stress responses. The most highly up-regulated genes included a tegument tetraspanin Sm-tsp-3 (1,600-fold up-regulation), a protein kinase, a novel serine protease and serine protease inhibitor, and intestinal proteases belonging to distinct mechanistic classes. The inclusion of erythrocytes in the culture medium resulted in a general but less pronounced increase in transcriptional activity, with the highest up-regulation of genes involved in iron metabolism, proteolysis, and transport of fatty acids and sugars.ConclusionsWe have identified the genes that are up-regulated during the first 5 days of schistosomula development in vitro. Using a combination of gene silencing techniques and murine protection studies, some of these highly up-regulated transcripts can be targeted for future development of new vaccines and drugs.
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Project description:Human nuclear receptor coactivator 4 (NcoA4) amplifies the activity of several ligand-activated nuclear transcription factors, including the aryl hydrocarbon receptor (AhR) and androgen receptor (AR). Because these receptors exert important regulatory effects during development, with AhR ubiquitously expressed after embryonic day 9.5 (E9.5) and AR expressed from E12 onward, we examined NcoA4 expression in mouse embryos from E9.5 to E17.5. Full-length NcoA4 transcript was detected by RT-PCR at all embryonic stages and in all adult mouse tissues examined, although a novel splice variant was also detected. Western blot analysis indicated the expression of full-length NcoA4 protein, which was more highly expressed at later (E15.5-E17.5) embryonic stages. NcoA4 protein was also present at varying levels in all adult mouse tissues examined. A dynamic expression profile for NcoA4 during early development was indicated by immunohistochemistry in cardiac, hepatic, and lung tissue. Unlike human NcoA4, murine NcoA4 lacks an LXXLL motif, which has been implicated in the interaction with AR. Overexpression of murine NcoA4 augmented the transcriptional activity of AhR by 5-fold and AR by only 1.5-fold in COS cells. These studies demonstrate ubiquitous NcoA4 expression throughout development and suggest that this coactivator may play a role in modulating nuclear receptor activity, particularly that of the AhR, during development.
| S-EPMC2889407 | biostudies-literature
Project description:Endometrioid or type-I endometrial carcinoma (EC) develops from hyperproliferative glandular pathologies. Inactivation of the tumor suppressor gene PTEN is frequently associated with type-I EC. Using a previously characterized Pten heterozygous (Pten+/-) mouse model, this study investigates the three-dimensional (3D) telomere profiles during progression from hyperplastic lesions to EC to test the hypothesis that altered 3D telomere profiles can be detected prior to Pten loss in early hyperproliferative lesions. We used immunohistochemistry and 3D-telomere fluorescent in-situ hybridization to investigate Pten expression, telomere length and signal distribution, average number and spatial distribution of telomeres and formation of telomere aggregates in uterine glandular epithelial cells from wildtype and Pten+/- mice. Pten showed nuclear and cytoplasmic localization in WT, predominantly cytoplasmic staining in simple hyperplasia (SH) and was markedly reduced in atypical hyperplasia (AH). Telomere length in glandular epithelial cells does not shorten with age. The average number of telomeres per nucleus was not different in WT and Pten+/- mice indicating the lack of substantial numeric chromosome aberrations during EC development. We observed telomere aggregates in lesions of AH and EC. SH lesions in Pten+/- mice differed from normal glandular epithelium by an increased relative number of shorter telomeres and by a telomere signal distribution indicative of a heterogeneous cell population. Our study revealed that alterations in the nuclear 3D telomere architecture are present in early proliferative lesions of mouse uterine tissues indicative of EC development. The changes in telomere length distribution and nuclear signal distribution precede the loss of Pten.
| S-EPMC5675068 | biostudies-literature