SEARCH · PubMed Health

Results for “Embryogenesis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 829 records · Page 46Linked to original sources

PubMed1996

Complementary tissue-specific expression of LIF and LIF-receptor mRNAs in early mouse embryogenesis.

The maintenance of pluripotential embryonic stem (ES) cells is dependent on the cytokine LIF. This report documents the mRNA expression profiles of LIF and the two components of the LIF-receptor complex, LIF-R and gp130, during early mouse embryogenesis. These mRNAs were undetectable in 1- or 2-cell embryos, but all were present by the blastocyst stage. LIF transcripts were localised in the differentiated trophectoderm, and were absent from the pluripotential inner cell mass. In contrast, LIF-R mRNA was found in the inner cell mass but not in the trophectoderm. This complementary pattern of expression is suggestive of a paracrine coupling between stem cells and differentiated progeny at the earliest stage of mammalian development. After implantation, transcripts for all components were down-regulated in the embryo. High levels of LIF-R and gp130 mRNAs were observed in the deciduum, however. These dynamic, tissue-specific expression patterns are consistent with regulatory roles for LIF or related cytokines, both in the maintenance of pluripotency in the mouse embryo, and in development of the foeto-maternal interface.

Animals↗

PubMed1996

The Drosophila gene alien is expressed in the muscle attachment sites during embryogenesis and encodes a protein highly conserved between plants, Drosophila and vertebrates.

We have found a novel gene (alien) that is expressed exclusively in the muscle attachment sites (apodemes) during embryogenesis in Drosophila. Antibodies raised against the Alien protein enable us to follow the developing attachments from state 11/12 until stage 16/17. The coding region of the Drosophila alien gene is highly conserved to a gene of unknown function, isolated from a plant (Loo et at., 1995), and to the human TRIP15 gene (Lee et al., 1995). Searching for thyroid receptor interacting proteins, TRIP15 was isolated as a negative regulator. Whether there is a functional correlation to Alien remains to be analyzed. Alien expression is independent of muscle formation, as shown in rolling stone mutant embryos. Even in twist and snail mutants, lacking mesodermal development, alien expression is fairly normal, showing a rather autonomous development of the apodemes. The conservation of alien suggests an important role in differentiation.

ATPases Associated with Diverse Cellular Activitie↗

PubMed1995

Chicken ovalbumin upstream promoter transcription factor (COUP-TF): expression during mouse embryogenesis.

Members of the steroid/thyroid hormone receptor superfamily such as TR, RAR, RXR and VDR are known to play important roles in regulation of gene expression during development, differentiation and homeostasis. COUP-TFs are orphan members of this superfamily of nuclear receptors and have been shown to negatively regulate the ability of these nuclear receptors to transactivate target genes. Two different mechanisms are implicated in this repression. First, COUP-TFs bind to AGGTCA direct repeats and palindromes with various spacings, which include response elements for TR, RAR, RXR and VDR, allowing for direct competition of COUP-TFs for the response elements. Second, COUP-TFs can heterodimerize with RXRs, the essential cofactor for effective binding of VDR, TRs and RARs to their cognate response elements. The physiological significance of this negative effect of COUP-TF on the activity of these receptors has been analyzed. Detection of COUP-TF transcripts during mouse development reveal discrete spatial and temporal expression domains consistent with COUP-TFs being involved in regulation of gene expression during embryogenesis. Transcripts are localized within discrete regions of the central and peripheral nervous system including the inner ear. In addition, COUP-TFs are found in many tissues including testes, ovary, prostate, skin, kidney, lung, stomach, intestine, pancreas and salivary gland. Some of these expression domains colocalize with those of TR, RAR, and RXR. The simultaneous expression of these genes raise the possibility that COUP-TFs can act as negative regulatory factors during development and differentiation.

Animals↗

PubMed2005

Regulation of growth-blocking peptide expression during embryogenesis of the cabbage armyworm.

Growth-blocking peptide (GBP) is an insect cytokine with diverse biological functions. Northern blot analysis revealed high heterogeneity in the size distribution of GBP mRNAs as well as in the tissues where they are detected. The spatio-temporal transcription pattern is dynamic, especially during embryogenesis. Gel shift assays demonstrated that the cabbage armyworm embryo nuclear extract specifically binds to a 178-bp element, at position +234 to +411 from the transcription start site of the 1.3 kb GBP transcript, in which two Drosophila Deformed (Dfd) binding sites are repeated in tandem. The specific binding between this element and Dfd was demonstrated using recombinant cabbage armyworm Dfd protein. Silencing the Dfd expression in embryos by treating with Dfd double-stranded RNA did not reduce the expression level of GBP, but ectopic GBP expression was observed in the lateral region of the embryo, suggesting that Dfd could serve as a transcriptional repressor for the GBP gene.

Amino Acid Sequence↗

PubMed2006

Two different late embryogenesis abundant proteins from Arabidopsis thaliana contain specific domains that inhibit Escherichia coli growth.

Late embryogenesis abundant (LEA) proteins constitute a set of proteins widespread in the plant kingdom that show common physicochemical properties such as high hydrophilicity and high content of small amino acid residues such as glycine, alanine, and serine. Typically, these proteins accumulate in response to water deficit conditions imposed by the environment or during plant normal development. In this work, we show that the over-expression in Escherichia coli of proteins of the LEA 2 and the LEA 4 families from Arabidopsis thaliana leads to inhibition of bacterial growth and that this effect is dependent on discrete regions of the proteins. Our data indicate that their antimicrobial effect is achieved through their interaction with intracellular targets. The relevance of the cationic nature and the predicted structural organization of particular protein domains in this detrimental effect on the bacteria growth process is discussed.

Amino Acid Sequence↗

PubMed2006

Expression of Tsga10 sperm tail protein in embryogenesis and neural development: from cilium to cell division.

Tsga10 has been localised in sperm tail as a fibrous sheath protein. In this study, we showed its expression during developmental stages of mouse embryo, in adult mice brain, and in some malignancies. RT-PCR and immunohistochemistry study show that Tsga10 expression starts in 4.5-7.5 dpc mouse embryos and continues throughout embryogenesis. Then we showed that the Tsga10 is expressed in adult brain and in the cells with neural crest origin, olfactory epithelium, and human germ cell tumour. It is expressed with two transcripts in sperm and whole embryos but just with the long transcript in brain embryo as a result of its exon 16 splicing. Our finding of the Tsga10 perinuclear localisation and its expression pattern suggests that it may be involved in active cell division, differentiation, and migrating cells. The results of the experiments in this project hypothesize the presence of Tsga10 protein wherever there is a conserved ciliary structure.

Alternative Splicing↗

PubMed2005

Expression of acetylcholinesterase (AChE) and aryl acylamidase (AAA) during early zebrafish embryogenesis.

In zebrafish, the onset of acetylcholinesterase (AChE) expression was detected by RT-PCR at 4 hpf (hours post-fertilization). The aryl acylamidase (AAA) associated with AChE, a serotonin sensitive activity with unknown physiological function, was significantly higher than the esterase activity on zebrafish embryos homogenates at 4-12 h development (test-t = 3.523; d.f. = 4). Remarkably, the ratio of AAA/AChE activity decreased 210-fold from 4 to 144 h development, indicating a distinct embryonic role of AAA during early embryogenesis. The AAA activity was sensitive to eserine and serotonin, ensuring its association with AChE. This is the first report of AAA activity on fish, establishing zebrafish as a model to study AAA on development.

Acetylcholinesterase↗

PubMed2005

Physiological and morphological characteristics of the rhythmic contractions of the amnion in veiled chameleon (Chamaeleo calyptratus) embryogenesis.

A morpho-functional study of the veiled chameleon (Chamaeleo calyptratus) amnion was performed as part of a general comparative study of amnion rhythmic contractions (ARC) in reptile and bird embryogenesis. Eggs incubated at 27.5 degrees C were used at different developmental stages from day 80 (D80) to D184 for the recording of ARC using a force transducer. Slow ARC, about 1 min in duration, were revealed from D88 (stage 31) to the near-hatching stages (incubation time was 183-198 days). The frequency and amplitude of slow ARC increased significantly towards the end of incubation. This ARC enhancement correlated with the differentiation of smooth muscle elements in the amniotic membrane from single spindle-shaped cells to complex "star-like" structures and with the development of the actin fibers, revealed by phalloidin, in the amniotic muscle layer. Short-term changes in temperature influenced ARC and heart rate (HR). Cooling to 25 degrees C from the control (27.5 degrees C) resulted in a significant decrease in both ARC frequency and HR. Heating to 30 degrees C significantly increased the embryonic HR, but not ARC frequency. Within the temperature range from 25 to 30 degrees C the temperature effect on ARC frequency and HR was reversible.

Actins↗

PubMed2005

Changes in amino acids and lipids during embryogenesis of European lobster, Homarus gammarus (Crustacea: Decapoda).

We studied the amino acid and lipid dynamics during embryogenesis of Homarus gammarus. Major essential amino acids (EAA) in the last stage of embryonic development were arginine, lysine and leucine; major nonessential amino acids (NEAA) were glutamic acid, aspartic acid, valine and glycine. The highest percent of utilization occurred in respect to EAA (27.8%), mainly due to a significant decrease (p<0.05) of methionine (38.3%) and threonine (36.0%). NEAA also decreased significantly (p<0.05, 11.4%), namely serine (38.1%), tyrosine (26.4%) and glutamic acid (25.7%). In contrast, the free amino acid content increased significantly (p<0.05) during embryonic development, especially the free nonessential amino acids (FNEAA). In the last stage, the most abundant FNEAA were glycine, proline, alanine and taurine, and the major free essential amino acids (FEAA) were arginine, lysine and leucine. Lipid content decreased significantly (p<0.05) during embryonic development. A substantial decrease in all neutral lipid classes was observed (>80% of utilization). Major fatty acids were 16:0, 18:0, 18:1n-9, 18:2n-6, 18:3n-3, 20:5n-3 and 22:6n-3. Unsaturated (UFA) and saturated fatty acids (SFA) were used up at similar rates (76.5% and 76.3%, respectively). Within UFA, monounsaturates (MUFA) were consumed more than polyunsaturates (PUFA) (82.9% and 67.5%, respectively).

Amino Acids↗

PubMed2005

Dehydration-regulated processing of late embryogenesis abundant protein in a desiccation-tolerant nematode.

Late embryogenesis abundant (LEA) proteins occur in desiccation-tolerant organisms, including the nematode Aphelenchus avenae, and are thought to protect other proteins from aggregation. Surprisingly, expression of the LEA protein AavLEA1 in A. avenae is partially discordant with that of its gene: protein is present in hydrated animals despite low cognate mRNA levels. Moreover, on desiccation, when its gene is upregulated, AavLEA1 is specifically cleaved to discrete, smaller polypeptides. A processing activity was found in protein extracts of dehydrated, but not hydrated, nematodes, and main cleavage sites were mapped to 11-mer repeated motifs in the AavLEA1 sequence. Processed polypeptides retain function as protein anti-aggregants and we hypothesise that the expression pattern and cleavage of LEA protein allow rapid, maximal availability of active molecules to the dehydrating animal.

Adaptation, Physiological↗

PubMed2004

Isolation of a new member of group 3 late embryogenesis abundant protein gene from a halotolerant green alga by a functional expression screening with cyanobacterial cells.

By a functional expression screening with cyanobacterial cells, a new member of group 3 late embryogenesis abundant protein genes (designated cw80lea3) was isolated from the cDNA library of halotolerant green alga Chlamydomonas sp. strain W80. The principle of the screening method was based on the acquisition of NaCl salt-tolerance of the fresh water cyanobacterial cells carrying the halotolerant algal gene. The expression of cw80lea3 gene in the C. W80 cells was induced by salt- and cold-stresses, but not by abscisic acid treatment.

Amino Acid Sequence↗

PubMed2004

Proteolytic activity of Boophilus microplus Yolk pro-Cathepsin D (BYC) is coincident with cortical acidification during embryogenesis.

In a previous report (Parasitology 116 (1998) 525) we isolated and characterized Boophilus Yolk pro-Cathepsin (BYC), an aspartic proteinase precursor from the eggs of the hard tick. The present study was designed to characterize the function of BYC in the consumption of vitellin (VT), the major yolk protein, during embryogenesis. Both purified BYC and total egg homogenate proteolytic activity showed a similar pH dependence profile with an acidic optimum. Purified BYC presented higher activity against VT as a substrate when compared to other proteins. The VT degradation pattern observed in vitro also showed a similar profile to that observed in vivo. Co-localization of BYC and acidic cortical yolk granules was performed by immunocytochemistry and confocal microscopy. Proton-pumping activity of yolk granules in vitro was higher in eggs collected 4 day after oviposition than in newly laid eggs. Taken together, our data suggest that BYC plays a major role in the degradation of VT and that its activity is controlled by acidification of yolk platelets localized at the cortical cytoplasm of the developing Boophilus microplus egg.

Animals↗

PubMedDate not supplied

Autism associated with conditions characterized by developmental errors in early embryogenesis: a mini review.

Autism is a complex developmental disorder without an established single etiology but with significant contributions from genetic studies, functional research, and neuropsychiatric and neuroradiologic investigations. The purpose of this paper is to review the findings in five studies involving individuals manifesting the characteristic findings of autism spectrum disorder associated with malformations and dysfunctions known to result from early embryogenic defects. These investigations include two associated with teratogens (thalidomide embryopathy, Mobius sequence with misoprostol) and three (most Mobius sequence cases, CHARGE association, Goldenhar syndrome) with no known etiology. These studies suggest that early embryonic development errors often involving cranial nerve palsies, internal and external ear malformations, ophthalmologic anomalies, and a variety of systemic malformations may be associated with autism spectrum disorders statistically more frequently than expected in a normal population. Although the exact time of developmental insult for each condition cannot be identified, the evidence is that it may occur as early as week 4 to 6+ of embryogenesis.

Abnormalities, Multiple↗

PubMed2006

Somatic embryogenesis and plant regeneration from leaf callus of Ocimum basilicum L.

A effective protocol for complete plant regeneration via somatic embryogenesis has been developed for Ocimum basilicum L. Callus was initiated from leaf explant of young plant on supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) 1.0 mg l(-1), 3% sucrose and 0.9% agar. The calli showed differentiation of globular structure embryos when transferred to MS medium containing 2,4-D 0.5 mg l(-1) and BAP 1.0 mg l(-1). The maximum globular structure embryos were further enlarged and produced somatic embryos in MS basal medium supplemented with BAP 1.0 mg l(-1)+NAA 1.0 mg l(-1) + KN 0.5 mg l(-1). Continued formation of globular embryo and germination of embryos occurred in this medium. Complete plantlets were transferred onto specially made plastic cup containing soilrite followed by their transfer to the garden soil. Survival rate of the plantlets under ex vitro condition was 80%.

Cell Culture Techniques↗

PubMed2005

Changes in competence for somatic embryogenesis in Norway spruce zygotic embryo segments.

Embryogenic capacity of Norway spruce zygotic embryo sections was drastically altered by a preinduction transfer to hormone-free medium for 7 or 14 days. An increase in competence for somatic embryogenesis was found with the cotyledons, while the hypocotyl sections completely lost their competence. These changes in competence were not dependent on physical contact between plant sections, and could not be correlated to the developmental stage of each section. The increase of competence in cotyledonary material was due not only to an increase of genotypes initiating somatic embryos, but also to an increase in embryogenicity of cotyledons.

Picea↗

PubMed2006

The Arabidopsis thaliana AAA protein CDC48A interacts in vivo with the somatic embryogenesis receptor-like kinase 1 receptor at the plasma membrane.

Fluorescent cell division cycle (CDC)48 proteins were studied in living plant protoplasts. CDC48A and somatic embryogenesis receptor like kinase 1 (SERK1) were found to co-localize in the endoplasmatic reticulum (ER) and at the plasma membrane (PM), but not in endosomal compartments. Fluorescent lifetime imaging microscopy (FLIM) was used to detect Förster resonance energy transfer (FRET) between CrFP/YFP-tagged CDC48A and SERK1. FRET is indicative of direct protein-protein interaction. CDC48A was found to interact only with SERK1 in small areas at the PM, but not in endosomes. These findings confirm and extend our previous findings that CDC48A in plants directly interacts with SERK1.

Arabidopsis↗

PubMedDate not supplied

Stress-induced apoptosis in sea urchin embryogenesis.

We find that early sea urchin embryos have the capability to induce programmed cell death, or apoptosis, in response to chemical and physical stress. Strongylocentrotus purpuratus embryos (fertilized, 4 cell, 16 cell, 64 cell, and early blastula) were exposed to known cytotoxins, in order to determine when apoptosis occurs naturally and in response to stress. Using cell permeability as an indicator of early stage apoptosis, caspase activation as a mid-stage indicator, and DNA fragmentation as a late stage indicator, we find that during the cleavage stage of embryogenesis apoptosis is almost completely absent. However, a statistically significant (p<0.001) rise in apoptosis in stressed embryos is evident around 24 h after fertilization, during the early blastula stage and shortly after hatching. Before this stage, exposed embryos show no statistically significant increases in apoptosis in comparison to the controls. This pattern of apoptosis in development is similar to that seen in lower vertebrate models in which stress-induced apoptosis occurs only around the mid-blastula transition. We conclude that apoptosis may be used to rid embryos of aberrant or damaged cells in early development, but this response is stage-dependant. Repair, rather than apoptosis, may be utilized during earlier stages, or alternatively, embryos exposed to such stressors may continue development with damaged cells and perhaps damaged DNA. Our continued studies will focus on these alternative hypotheses.

4-Aminobenzoic Acid↗

PubMed2003

Patterns and functions of STAT activation during Drosophila embryogenesis.

The JAK/STAT pathway mediates cytokine signaling in mammals and is involved in the function and development of the hematopoietic and immune systems. To investigate the biological functions of the JAK/STAT pathway during Drosophila development, we examined the tissue-specific localization of the tyrosine-phosphorylated, or activated form of Drosophila STAT, STAT92E. Here we show that during Drosophila embryonic development STAT92E activation is prominently detected in multiple tissues and in different developmental stages. These tissues include the tracheal pits, elongating intestinal tracks, and growing axons. We demonstrate that stat92E mutants are defective in tracheal formation, hindgut elongation, and nervous system development. Conversely, STAT92E overactivation caused premature development of the tracheal and nervous systems, and over-elongation of the hindgut. These results suggest that STAT activation is involved in proper differentiation and morphogenesis of multiple tissues during Drosophila embryogenesis.

Animals↗