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PubMed2026

Transcription regulation of cell fate plasticity - from embryonic development to tissue regeneration.

Cell fate plasticity refers to the capacity of cells sharing the same genome to alter, reverse, or reconfigure their identity under physiological, pathological, or experimental conditions. This property underlies embryonic development, cellular reprogramming, and tissue regeneration, but becomes progressively restricted as lineage identity is stabilized. Embryonic development represents an intrinsic process of fate transitions, whereas reprogramming and regeneration reveal how differentiated cells can dedifferentiate or transdifferentiate under specific conditions. Across these contexts, plasticity is governed by multilayered regulatory networks involving transcription factors, epigenetic regulators, cofactors, and the core transcription machinery. Robust regulatory programs stabilize cell identity, whereas stochastic fluctuations in gene expression and chromatin state can prime cells for fate transitions, adding a tunable dimension to plasticity control. In this review, we synthesize recent advances in the regulation of cell fate plasticity across development, reprogramming, and regeneration, highlighting how transcription factors, epigenetic modifications, transcriptional cofactors, and core transcription machinery cooperate to control cell fate decisions and plasticity.

Animals↗
PubMed2000

[Study on the effect of alcohol on embryonic development by using in vitro post-implantation rat whole embryo culture].

In order to explore the effects of drinking alcohol during pregnancy on embryonic development and its mechanisms, a post-implantation whole embryo culture(WEC) technique was used. The 9.5 day rat embryos were explanted in rat serum medium(immediately centrifugal serum, ICS) with alcohol(0.0.4.1.0, 2.00 and 4.00 g/L), and cultured for 48 hours. The index of embryo development and morphological scores induced by alcohol were observed. The result showed that alcohol had obviously effects on the development and growth of embryos with a dose-response relationship. Embryonic development of 0.4 g/L group was not significantly different from the control group, whereas 1.0 g/L group could interfere with the development score of mid-brain, forebrain, neurotube, and visceral yolk sac(VYS) circle obviously. All scores of the 2.00 g/L group were significantly lower than that of control group (P < 0.05). Moreover, the rate of embryo lethality and teratogenecity were obvious increased. It is concluded that alcohol has developmental toxicity and teratogenicity. The target organ affected by alcohol is brain. The effects of alcohol on the developmental differentiation of visceral yolk sac and DNA synthesis are probably related to its developmental abnormalities.

Animals↗
PubMed1975

A light and electron microscopic study on the embryonic development of the rat carotid body.

The embryonic development of the rat carotid body was studied with electron microscopy. In the 11 mm embryo a cell aggregation consisting of undifferentiated cells and unmyelinated nerve fibers appears on the anterior wall of the third branchial artery. Granule-containing cells appear in the 12 mm embryo and continue to increase in number as the cellular aggregation increases in size and becomes separated from the wall of the third branchial artery. Synapse formation and the appearance of fenestrated capillaries occur almost simultaneously at the 17 mm stage. There are two types of synapses, one with membrane densification and vesicles clustered inside the nerve endings, the other with dense material and vesicles inside the granule-containing cells. At the 20 mm stage the undifferentiated cells send enveloping cytoplasmic processes toward adjacent granule-containing cells and the carotid body anlage displays rudimentary lobules.

Animals↗
PubMed1981

Embryonic development of the rat pineal gland.

The embryonic development of the albino rat pineal gland has been studied from day 13 of development until birth. The first pineal anlage appears as a midline evagination of the diencephalic roof, which soon adopts a tubular morphology. At 17 days, the disappearance of the pineal recess begins, along with the transformation of the gland into a solid organ. The latter is mainly achieved by an infolding and thickening of the dorsal recess wall, from which derives most of the future pineal parenchyma. Blood vessels are mainly derived from the vessels found in the dorsal surface of the pineal gland.

Animals↗
PubMed1991

Molecular mechanisms separating two axonal pathways during embryonic development of the avian optic tectum.

During embryonic development of the avian optic tectum, retinal and tectobulbar axons form an orthogonal array of nerve processes. Growing axons of both tracts are transiently very closely apposed to each other. Despite this spatial proximity, axons from the two pathways do not intermix, but instead restrict their growth to defined areas, thus forming two separate plexiform layers, the stratum opticum and the stratum album centrale. In this study we present experimental evidence indicating that the following three mechanisms might play a role in segregating both axonal populations: Retinal and tectobulbar axons differ in their ability to use the extracellular matrix protein laminin as a substrate for axonal elongation; the environment in the optic tectum is generally permissive for retinal axons, but is specifically nonpermissive for tectobulbar axons, resulting in a strong fasciculation of the latter; and growth cones of temporal retinal axons are reversibly inhibited in their motility by direct contact with the tectobulbar axon's membrane.

Animals↗
PubMedDate not supplied

Sperm morphology and preparation method affect bovine embryonic development.

This study was conducted to evaluate the effect of sperm separation methods of semen samples collected from bulls subjected to scrotal insulation on embryonic development after in vitro fertilization (IVF) and to determine whether IVF results would be affected by various heparin concentrations. Morphologically abnormal semen samples were obtained and cryopreserved from Holstein bulls following scrotal insulation for 48 hours. Standard protocols using the Percoll gradient (90%/45%) method and the swim-up method were used to separate spermatozoa fractions in experiment I. The pellet (A(p)) and the 45% layer (B(p)) were isolated from the Percoll separation, while for the swim-up separation, the supernatant (A(s)) and the interphase (B(s)) were isolated. The overall blastocyst rate for our laboratory control semen was 23.1 +/- 2.1% for Percoll separations (A(p) and B(p)) and 18.2 +/- 2.0% for swim-up (A(s) and B(s)) separations. This rate was higher (P <.01) than the rate observed for the semen from the bull that had the greatest response to scrotal insult 5 days prior to the insult, when it was 9.2 +/- 2.1% for the Percoll separation and 20.7 +/- 2.3% for the swim-up separation, while semen from 27 days after scrotal insulation (D +27) resulted in no blastocyst formation for the Percoll separation and a 4.2 +/- 2.1% rate for the swim-up separation. In experiment II, semen was sampled from the bulls that responded in the greatest and least degrees to scrotal insult 5 days before scrotal insulation (D -5) and on days 23 (D +23) and 34 (D +34) after scrotal insulation. These samples were exposed to IVF mediums with 3 different heparin concentrations (0.1, 1.0, and 10 microg/mL). There was a significant difference (P <.05) in developmental scores between the D -5 (1.08 +/- 0.08), D +23 (0.9 +/- 0.08), and D +34 (0.8 +/- 0.08) samples, but no differences were observed in blastocyst formation based on the number of cleaved embryos. Increasing the heparin concentration resulted in higher (P <.01) embryonic developmental scores. In conclusion, when semen samples with high percentages of abnormal spermatozoa are used for IVF, semen separation preparation methods affect results. Our results show that the separation methods used under these conditions were inadequate in their ability to provide potentially competent sperm for IVF. However, selecting appropriate sperm separation procedures could improve in the IVF embryonic development of semen from bulls used in artificial insemination. Also, an increase in the heparin concentration was able to partially overcome deficiencies, which suggests that morphologically abnormal spermatozoa undergo capacitation despite possible structural changes to the plasma membrane.

Animals↗
PubMed2003

Miz1 is required for early embryonic development during gastrulation.

Miz1 is a member of the POZ domain/zinc finger transcription factor family. In vivo, Miz1 forms a complex with the Myc oncoprotein and recruits Myc to core promoter elements. Myc represses transcription through Miz1 binding sites. We now show that the Miz1 gene is ubiquitously expressed during mouse embryogenesis. In order to elucidate the physiological function of Miz1, we have deleted the mouse Miz1 gene by homologous recombination. Miz1(+/-) mice are indistinguishable from wild-type animals; in contrast, Miz1(-/-) embryos are not viable. They are severely retarded in early embryonic development and do not undergo normal gastrulation. Expression of Goosecoid and Brachyury is detectable in Miz1(-/-) embryos, suggesting that Miz1 is not required for signal transduction by Nodal. Expression of p21Cip1, a target gene of Miz1 is unaltered; in contrast, expression of p57Kip2, another target gene of Miz1 is absent in Miz1(-/-) embryos. Miz1(-/-) embryos succumb to massive apoptosis of ectodermal cells around day 7.5 of embryonic development. Our results show that Miz1 is required for early embryonic development during gastrulation.

Animals↗
PubMed2004

Immunohistochemical study of adenohypophysial cells during embryonic development in the reptile Chalcides chalcides (Squamata, Scincidae).

The immunohistochemical avidin-biotin complex method was used to study hormone-producing cells in the adenohypophysis of the skink Chalcides chalcides during embryonic development. In Chalcides, the formation of Rathke's pouch was evident between stages 28 and 30 of embryonic development. The adenohypophysial cells begin to differentiate before the morphological development of the gland was complete. At stage 29, few corticotropic cells were present only in the dorsal face of Rathke's pouch. No other immunoreactive cell type was revealed at this stage. At stage 32, the hypophysis had developed to a great extent though it was not yet elongated in a cephalic-caudal direction. At this stage, the corticotropic cells appeared more numerous and well differentiated in the rostral pars distalis and in the pars intermedia. Melanotropic, somatotropic and gonadotropic cells appeared simultaneously, with the same distributions as in the adult skink. At stage 34, the first thyrotropic cells appeared in the pars distalis but also in the pars intermedia, whereas rare prolactin cells were observed only at stage 35 in the medial pars distalis. Between stages 36 and 38, the gland was developed in the cephalic-caudal direction and all the cell types were completely differentiated with an evident increase in the number of prolactin cells. In embryos close to birth (stages 39-40), the hypophysis and the adenohypophysial cells were already similar to those of the adult animal.

Animals↗
PubMed2006

Role of two glycosidases (alpha-mannosidase and beta-N-acetylglucosaminidase) on in vitro bovine embryonic development.

Glycosidases are enzymes that might play a role in embryonic development. The aims of the present project were to evaluate if bovine in vitro produced embryos: (1) release beta-N-acetylglucosaminidase (beta-NAGASE) and alpha-mannosidase in culture medium and (2) to investigate if these glycosidases may be used as markers of embryo quality. Bovine embryos were obtained using routine methods for IVM, IVF and IVC. Two experiments were done [(experiment 1: culture of embryos in the same droplet until day 7 and experiment 2: separation and transfer of embryos to new droplets at the morula stage (day 6)]. Samples were collected on day 7 (experiment 1) and on days 6 and 7 (experiment 2). The results of the present study are summarized as follow: (i) Embryos release both glycosidases. (ii) The activity of both glycosidases was significantly lower (p<0.05) in droplets with degenerate embryos compared to droplets without degenerate embryos. (iii) The activity of beta-NAGASE was higher in droplets which contained morulae compared to droplets without morulae. In conclusion, embryos release both glucosidases during their development, while degenerate embryos release less beta-NAGASE and alpha-mannosidase compared to good embryos. Furthermore, beta-NAGASE secretion seems to be related to retarded morulae.

Acetylglucosaminidase↗
PubMed2006

Nitric oxide affects preimplantation embryonic development in a rotating wall vessel bioreactor simulating microgravity.

Microgravity was simulated with a rotating wall vessel bioreactor (RWVB) in order to study its effect on pre-implantation embryonic development in mice. Three experimental groups were used: stationary control, rotational control and clinostat rotation. Three experiments were performed as follows. The first experiment showed that compared with the other two (control) groups, embryonic development was significantly retarded after 72 h in the clinostat rotation group. The second experiment showed that more nitric oxide (NO) was produced in the culture medium in the clinostat rotation group after 72 h (P<0.05), and the nitric oxide synthase (NOS) activity in this group was significantly higher than in the controls (P<0.01). In the third experiment, we studied apoptosis in the pre-implantation mouse embryos after 72 h in culture and found that Annexin-V staining was negative in the normal (stationary and rotational control) embryos, but the developmentally retarded (clinostat rotation) embryos showed a strong green fluorescence. These results indicate that microgravity induced developmental retardation and cell apoptosis in the mouse embryos. We presume that these effects are related to the higher concentration of NO in the embryos under microgravity, which have cause cytotoxic consequences.

Animals↗
PubMed1993

[Studies in oocyte maturation and embryonic development].

A clearer understanding of biochemical properties of oocytes and embryos and their changes in oocyte maturation and embryonic development may have significant clinical implications, especially for in vitro fertilization techniques. Microtechniques and highly sensitive methods such as enzymatic cycling, micro-Western analysis, reverse transcription polymerase chain reaction and so on were employed to study these processes. Low hexokinase activity and high activities of enzymes in the phosphate pathway were characteristic of immature oocytes. During maturation, the activities of hexokinase and phosphofructokinase increased significantly. These changes were used to analyze involvement of epidermal growth factor (EGF) and prostaglandins (PG) in oocyte maturation. EGF is shown to stimulate maturation by increasing PG production in granulosa cells. Electrophysiologically, the sensitivity of oocyte to inositol triphosphate increased and Ca2+ release system developed during maturation. Progesterone production of oocyte and embryos are shown by enzymatic cycling and other methods using radiometry. This hormone produced by embryos themselves may play a role in embryonic development in intracrine fasion. There is 100-fold increase in glucose uptake from oocyte to blastocyst in mice. A switch in substrate preference of the embryo from pyruvate to glucose during preimplantation development may be explained by increases in the activity of hexokinase and expression of glucose transporter, GLUT1. Hexokinase activities determined by NADP cycling increased 20-fold while expression of GLUT1 assessed by micro-Western method 10-fold. GLUT1 expression was also analyzed by RT-PCR, which indicated that the expression is regulated at transcription level. There is a delay in the developmental changes in glucose uptake, hexokinase activity and GLUT1 expression when the embryos are developed in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

Changing intracellular compartmentalization of beta-galactosidase in the ROSA26 reporter mouse during embryonic development: a light- and electron-microscopic study.

The beta-geo (LacZ) reporter gene encodes for beta-galactosidase (beta-gal) in all cells of the ROSA26 mouse during embryonic development. As such, beta-gal activity constitutes an excellent marker for in situ labeling of expressing cells. However, the intracellular distribution of beta-gal differs between cells, and changes during embryonic development. Therefore, we studied LacZ-encoded beta-gal using light and electron microscopy in the heart, lung, liver, and small intestine on days 13 and 16 of gestation, and the kidney on day 16 of gestation in ROSA26 mice. The Bluo-gal method was carried out under standardized conditions, including fixation, washing, and incubation procedures. Intracellular beta-gal staining is encountered in a combination of membranous compartments, including the nuclear envelope, the endoplasmic reticulum, and the plasma membrane. Its exact localization depends on the cell type and is regulated during development. Therefore, one must take the compartmental transition of intracellular beta-gal staining into consideration when interpreting results obtained from experiments using ROSA26 mice.

Animals↗
PubMed2006

The zinc finger transcription factor 191 is required for early embryonic development and cell proliferation.

Human zinc finger protein 191 (ZNF191/ZNF24) was cloned and characterized as a SCAN family member, which shows 94% identity to its mouse homologue zinc finger protein 191 (Zfp191). ZNF191 can specifically interact with an intronic polymorphic TCAT repeat (HUMTH01) in the tyrosine hydroxylase (TH) gene. Allelic variations of HUMTH01 have been stated to have a quantitative silencing effect on TH gene expression and to correlate with quantitative and qualitative changes in the binding by ZNF191. Zfp191 is widely expressed during embryonic development and in multiple tissues and organs in adult. To investigate the functions of Zfp191 in vivo, we have used homologous recombination to generate mice that are deficient in Zfp191. Heterozygous Zfp191(+/-) mice are normal and fertile. Homozygous Zfp191(-/-) embryos are severely retarded in development and die at approximately 7.5 days post-fertilization. Unexpectedly, in Zfp191(-/-) and Zfp191(+/-) embryos, TH gene expression is not affected. Blastocyst outgrowth experiments and the RNA interference-mediated knockdown of ZNF191 in cultured cells revealed an essential role for Zfp191 in cell proliferation. In further agreement with this function, no viable Zfp191(-/-) cell lines were obtained by derivation of embryonic stem (ES) cells from blastocysts of Zfp191(+/-) intercrosses or by forced homogenotization of heterozygous ES cells at high concentrations of G418. These data show that Zfp191 is indispensable for early embryonic development and cell proliferation.

Animals↗
PubMed2006

Effects of plane of nutrition on in vitro fertilization and early embryonic development in sheep.

Nutrition has been shown to influence several reproductive functions, including hormone production, oocyte competence and fertilization, and early embryonic development. To determine the effects of maternal diet on in vitro fertilization (IVF) and early embryonic development, ewes (n = 18; 47.0 +/- 1.5 kg of initial BW) were divided into control and underfed (60% of control) nutritional planes for 8 wk before oocyte collection. Pelleted diets containing 2.4 Mcal of ME/kg and 13% CP (DM basis) were fed once daily. During the first 4-wk acclimation phase, control and underfed ewes were fed 1,000 and 600 g/d, respectively. From wk 4 to 8, control (adequate) ewes were fed to maintain BW and offered 720 g/d, whereas underfed ewes received 432 g/d (60% restricted). Synchronization of estrus was performed using progestagen sponges for 14 d. Follicular development was induced by twice daily injections of FSH on d 13 (5 units/injection) and 14 (4 units/injection) of the estrous cycle. Oocytes were collected from all visible follicles on d 15 of the estrous cycle. After IVF, the proportion of developing embryos was evaluated throughout an 8-d culture period. Under-nutrition decreased (P < 0.006) the rate of cleavage, number of blastocysts per ewe, and rate of blastocyst formation (from 79 to 64%; from 3.3 to 0.8; and from 31 to 8%, respectively). However, the number of visible follicles, total number of oocytes, number of healthy oocytes, percentage of healthy oocytes, number of cleaved oocytes, and morula formation per ewe were similar for control and underfed ewes. These data indicate that undernutrition of donor ewes, resulting in lower BW and BCS, has a negative effect on oocyte quality, which results in lower rates of cleavage and blastocyst formation.

Animal Feed↗
PubMed1988

Effects of oxygen concentration on embryonic development in rats: a light and electron microscopic study using whole-embryo culture techniques.

By using a whole-embryo culture technique (New 1978), the effects of oxygen concentration (5%, 20% and 95% oxygen) on embryonic development in the rat were investigated by light and electron microscopy. The best embryonic development occurred when the 9.5-day-old embryos were cultured for 24 h with 5% oxygen, and the 10.5-day-old embryos with 20% oxygen (optimum oxygen concentration). When the 9.5- and 10.5-day-old embryos were cultured for 24 h with too little or too much oxygen, retardation of the embryonic growth and abnormal development was observed. Using light microscopy, numerous degenerating cells, exhibiting granular deposits in the cytoplasm, were seen, but the distribution of the degenerating cells was quite different between the two groups. With electron microscopy, the most striking feature of the degenerating cells in the embryos cultured with too little oxygen, was the extreme swelling of the mitochondria without any morphological alterations of the nucleus or the other cell organelles. On the other hand, the characteristic feature of the degenerating cells in the embryos exposed to too much oxygen, was the formation of phagolysosomes in the cytoplasm. Morphological alterations of the nucleus or mitochondria were not evident. In the present study, the possible teratogenic mechanism of too much or too little oxygen in the whole-embryo culture of the rat embryo is discussed.

Animals↗
PubMed2006

Triose phosphate isomerase, a novel enzyme-crystallin, and tau-crystallin in crocodile cornea. High accumulation of both proteins during late embryonic development.

Several enzymes are known to accumulate in the cornea in unusually high concentrations. Based on the analogy with lens crystallins, these enzymes are called corneal crystallins, which are diverse and species-specific. Examining crystallins in lens and cornea in multiple species provides great insight into their evolution. We report data on major proteins present in the crocodile cornea, an evolutionarily distant taxon. We demonstrate that tau-crystallin/alpha-enolase and triose phosphate isomerase (TIM) are among the major proteins expressed in the crocodile cornea as resolved by 2D gel electrophoresis and identified by MALDI-TOF. These proteins might be classified as putative corneal crystallins. tau-Crystallin, known to be present in turtle and crocodile lens, has earlier been identified in chicken and bovine cornea, whereas TIM has not been identified in the cornea of any species. Immunostaining showed that tau-crystallin and TIM are concentrated largely in the corneal epithelium. Using western blot, immunofluorescence and enzymatic activity, we demonstrate that high accumulation of tau-crystallin and TIM starts in the late embryonic development (after the 24th stage of embryonic development) with maximum expression in a two-week posthatched animal. The crocodile corneal extract exhibits significant alpha-enolase and TIM activities, which increases in the corneal extract with development. Our results establishing the presence of tau-crystallin in crocodile, in conjunction with similar reports for other species, suggest that it is a widely prevalent corneal crystallin. Identification of TIM in the crocodile cornea reported here adds to the growing list of corneal crystallins.

Alligators and Crocodiles↗
PubMed1999

[Characterization and stage-specific change of proteins during the embryonic development of silkworm Bombyx mori].

The gene expression pattern was analysed employing protein two-dimensional electrophoresis and amino acid sequencing during the embryonic development of silkworm Bombyx mory. The 2D-PAGE pattern of the silkworm embryonic proteins had little change in the long developmental period from the Critical Stage until the Head Pigmentation Stage of silkworm embryo. The percentage of matched proteins that found between the spots in the 2D-PAGE pattern of the Critical Stage of silkworm embryo and the spots in the 2D-PAGE pattern of the Head Pigmentation Stage of silkworm embryo was 63%. Silkworm Egg-specific Protein and 30K Protein were in large amount. However, 2D-PAGE pattern of the silkworm embryonic proteins showed considerably varied in shorter developmental stage from the Head Pigmentation Stage to the Body Pigmentation Stage and until the Newly Hatched Larva. The percentage of matched proteins that found the spots in the 2D-PAGE pattern of each developmental stage of silkworm embryo became lesser. The protein spots that the isoelectric points lying on the acidic side greatly increased, the Silkworm Egg-specific Protein and 30K Protein were gradually disappeared and the gene that resembles BmLSP's, Enolase's and Superoxide dismutase's gene was activated and expressed with the embryonic development.

Amino Acid Sequence↗