Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Embryonic Induction”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 433 records · Page 24Linked to original sources
PubMed1995

Evidence for involvement of activin A and bone morphogenetic protein 4 in mammalian mesoderm and hematopoietic development.

Xenopus in vitro studies have implicated both transforming growth factor beta (TGF-beta) and fibroblast growth factor (FGF) families in mesoderm induction. Although members of both families are present during mouse mesoderm formation, there is little evidence for their functional role in mesoderm induction. We show that mouse embryonic stem cells, which resemble primitive ectoderm, can differentiate to mesoderm in vitro in a chemically defined medium (CDM) in the absence of fetal bovine serum. In CDM, this differentiation is responsive to TGF-beta family members in a concentration-dependent manner, with activin A mediating the formation of dorsoanterior-like mesoderm and bone morphogenetic protein 4 mediating the formation of ventral mesoderm, including hematopoietic precursors. These effects are not observed in CDM alone or when TGF-beta 1, -beta 2, or -beta 3, acid FGF, or basic FGF is added individually to CDM. In vivo, at day 6.5 of mouse development, activin beta A RNA is detectable in the decidua and bone morphogenetic protein 4 RNA is detectable in the egg cylinder. Together, our data strongly implicate the TGF-beta family in mammalian mesoderm development and hematopoietic cell formation.

Activins↗
PubMed1990

Pax8, a murine paired box gene expressed in the developing excretory system and thyroid gland.

Several mouse genes designated 'Pax genes' contain a highly conserved DNA sequence homologous to the paired box of Drosophila. Here we describe the isolation of Pax8, a novel paired box containing clone from an 8.5 day p.c. mouse embryo cDNA library. An open reading frame of 457 amino acids (aa) contains the 128 aa paired domain near the amino terminus. Another conserved region present in some other paired box genes, the octapeptide Tyr-Ser-Ile-Asn-Gly-Leu-Leu-Gly, is located 43 aa C-terminal to the paired domain. Using an interspecies backcross system, we have mapped the Pax8 gene within the proximal portion of mouse chromosome 2 in a close linkage to the surf locus. Several developmental mutations are located in this region. In situ hybridization was used to determine the pattern of Pax8 expression during mouse embryogenesis. Pax8 is expressed transiently between 11.5 and 12.5 days of gestation along the rostrocaudal axis extending from the myelencephalon throughout the length of the neural tube, predominantly in two parallel regions on either side of the basal plate. We also detected Pax8 expression in the developing thyroid gland beginning at 10.5 days of gestation, during the thyroid evagination. In the mesonephros and metanephros the expression of Pax8 was localized to the mesenchymal condensations, which are induced by the nephric duct and ureter, respectively. These condensations develop to functional units, the nephrons, of the kidney. These data are consistent with a role for Pax8 in the induction of kidney epithelium. The embryonic expression pattern of Pax8 is compared with that of Pax2, another recently described paired box gene expressed in the developing excretory system.

Amino Acid Sequence↗
PubMed1992

[Function, molecular structure and gene expression of fibroblast growth factor (FGF/HBGF)].

The structure and function of members of the fibroblast growth factor (FGF) gene family and their receptors are reviewed. All the member of this gene family bind heparin, and therefore, are also called the as heparin-binding growth factor (HBGF). In this review, the structural features of FGF/HBGF are summarized first, and general features of the structure and function of their receptors are then described briefly. After biological effects of FGF/HBGF on adult-type tissues and cultured cells are reviewed, effects of FGF on the mesodermal induction in amphibian (Xenopus laevis) embryonic system are reviewed in more detail. Emphasis is given on the experiments with Xenopus animal cap assay system and also on the injection into Xenopus fertilized eggs of mRNA of dominant defect mutant of FGF receptor, which leads to the formation of embryos with abnormal axial mesoderm.

Animals↗
PubMed1993

Induction and axial patterning of the neural plate: planar and vertical signals.

In this review I summarize recent findings on the contributions of different cell groups to the formation of the basic plan of the nervous system of vertebrate embryos. Midline cells of the mesoderm--the organizer, notochord, and prechordal plate--and midline cells of the neural ectoderm--the notoplate and floor plate--appear to have a fundamental role in the induction and patterning of the neural plate. Vertical signals acting across tissue layers and planar signals acting through the neural epithelium have distinct roles and cooperate in induction and pattern formation. Whereas the prechordal plate and notochord have distinct vertical signaling properties, the initial anteroposterior (A-P) pattern of the neural plate may be induced by planar signals originating from the organizer region. Planar signals from the notoplate may also contribute to the mediolateral (M-L) patterning of the neural plate. These and other findings suggest a general view of neural induction and axial patterning.

Animals↗
PubMed1993

T cell response to embryonal carcinoma F9 cells: induction and characterization of T cell receptor alpha beta+ double-negative cytotoxic T lymphocytes.

We investigated the mechanism of T cell response to murine embryonal carcinoma F9 cells. Thy-1+, CD4-, CD8- (double-negative) cytotoxic effector cells were induced in spleen cells obtained from immune A.BY mice to F9 cells, and the cytotoxic activity was major histocompatibility complex (MHC)-unrestricted. Furthermore, CD4+ T cells were essential for the induction of double-negative cytotoxic T lymphocytes directed to F9 cells. Most of the double-negative cytotoxic T lymphocyte lines obtained by long-term culture of the effector cells had CD3 molecule and T-cell receptor beta chain on their cell surface, and the CD3 molecule was found to be involved in target cell recognition. The T cell receptor alpha beta+ double-negative cytotoxic T lymphocyte line (2A5) also lysed various tumor cells in a non-MHC-restricted manner, but did not lyse concanavalin A-stimulated blasts of 129 strain, from which F9 cells had originated. These results indicate that T cell receptor alpha beta+ double-negative cytotoxic T lymphocytes induced by F9 cells recognize a common antigen(s) expressed on F9 cells and other tumor cells but not minor histocompatibility antigens.

Animals↗
PubMed1989

Peptidergic properties expressed in vitro by embryonic neuroblasts after neural induction.

As an immediate consequence of neural induction, some neuroectodermal cells acquire the ability to develop a number of characteristic neuronal features, without requiring any subsequent embryonic cues (Duprat et al. 1987). Thus, adrenergic, cholinergic and gabaergic traits are expressed in cultures of neural fold and neural plate isolated from amphibian embryos immediately after induction and grown in a defined medium. The aim of the present study was to determine, using the same in vitro model, their abilities to develop peptidergic phenotypes. Using immunocytochemical techniques, we show that substance P-, enkephalin- (leu-enkephalin, metenkephalin), and somatostatin- like immunoreactivities are expressed in subpopulations of neurones grown in vitro, whereas VIP (vasoactive intestinal polypeptide) is not detected under the same conditions. The appearance and development of the somatostatinergic phenotype has been quantified by RIA both in cell extracts and in the culture medium. Somatostatin-like immunoreactivity (SLI) undetectable at the late gastrula stage, can be measured in cells after 4 days of culture and continues to increase over the next 10 days. In culture medium, SLI is present at a constant level from day 4 up to day 14. These data reveal that some neuronal precursor cells acquire, during neural induction, the potentiality to biosynthesize, store and release neuropeptides. Furthermore, the expression of these peptidergic phenotypes in distinct subpopulations of neurones suggests that certain neuronal precursors become committed to different metabolic pathways at the earliest steps of neurogenesis.

Animals↗
PubMed1992

The development of the mouse kidney--embryogenesis writ small.

Kidney development starts with an epithelial bud and a domain of committed mesenchyme inducing one another so that the former gives a bifurcating duct system and the latter nephrons. As these events take place in vitro, the mechanisms underpinning nephrogenesis can be investigated experimentally. Recent work has shown the diversity of regulatory molecules expressed during kidney development and begun to clarify the molecular basis of mesenchyme induction, but there is more to come.

Animals↗
PubMed1971

Vitamin D3: induction of calcium-binding protein in embryonic chick intestine in vitro.

Induction of the synthesis of calcium-binding protein in chick embryonic intestine maintained in vitro was accomplished by simply adding vitamin D(3) to the culture medium. Accompanying the induction of this protein, there was enhanced radiocalcium uptake by the intestine. These observations represent the first demonstration of an in vitro physiological effect of vitamin D(3) on the calcium absorptive mechanism of the intestine.

Animals↗
PubMed2005

Nuclear integration of positive Dpp signals, antagonistic Wg inputs and mesodermal competence factors during Drosophila visceral mesoderm induction.

Tissue induction during embryonic development relies to a significant degree on the integration of combinatorial regulatory inputs at the enhancer level of target genes. During mesodermal tissue induction in Drosophila, various combinations of inductive signals and mesoderm-intrinsic transcription factors cooperate to induce the progenitors of different types of muscle and heart precursors at precisely defined positions within the mesoderm layer. Dpp signals are required in cooperation with the mesoderm-specific NK homeodomain transcription factor Tinman (Tin) to induce all dorsal mesodermal tissue derivatives, which include dorsal somatic muscles, the dorsal vessel and visceral muscles of the midgut. Wingless (Wg) signals modulate the responses to Dpp/Tin along anteroposterior positions by cooperating with Dpp/Tin during dorsal vessel and somatic muscle induction while antagonizing Dpp/Tin during visceral mesoderm induction. As a result, dorsal muscle and cardiac progenitors form in a pattern that is reciprocal to that of visceral muscle precursors along the anteroposterior axis. Our present study addresses how positive Dpp signals and antagonistic Wg inputs are integrated at the enhancer level of bagpipe (bap), a NK homeobox gene that serves as an early regulator of visceral mesoderm development. We show that an evolutionarily conserved bap enhancer element requires combinatorial binding sites for Tin and Dpp-activated Smad proteins for its activity. Adjacent binding sites for the FoxG transcription factors encoded by the Sloppy paired genes (slp1 and slp2), which are direct targets of the Wg signaling cascade, serve to block the synergistic activity of Tin and activated Smads during bap induction. In addition, we show that binding sites for yet unknown repressors are essential to prevent the induction of the bap enhancer by Dpp in the dorsal ectoderm. Our data illustrate how the same signal combinations can have opposite effects on different targets in the same cells during tissue induction.

Animals↗
PubMed2005

Neural induction: old problem, new findings, yet more questions.

During neural induction, the embryonic neural plate is specified and set aside from other parts of the ectoderm. A popular molecular explanation is the 'default model' of neural induction, which proposes that ectodermal cells give rise to neural plate if they receive no signals at all, while BMP activity directs them to become epidermis. However, neural induction now appears to be more complex than once thought, and can no longer be fully explained by the default model alone. This review summarizes neural induction events in different species and highlights some unanswered questions about this important developmental process.

Animals↗
PubMed1994

Glutamine transaminase K and omega-amidase activities in primary cultures of astrocytes and neurons and in embryonic chick forebrain: marked induction of brain glutamine transaminase K at time of hatching.

Glutamine transaminase K and omega-amidase activities are present in the chick brain and in the brains of adult mice, rats, and humans. However, the activity of glutamine transaminase K in adult mouse brain is relatively low. In the chick embryo, cerebral glutamine transaminase K activity is low between embryonic days 5 and 17, but by day 23 (day of hatching) activity rises dramatically (> 15-fold). Cerebral omega-amidase activity is relatively high at embryonic day 5 but lower between days 5 and 17; at embryonic day 23 the activity rises to a maximum. Both glutamine transaminase K and omega-amidase are present in cultured chick, rat, and mouse astrocytes and neurons. For each species, the activity of glutamine transaminase K is higher in the astrocytes than in the neurons. The activity of omega-amidase is about the same in the cultured chick astrocytes and neurons but significantly higher in rat astrocytes than in rat neurons. The data suggest that the rise in brain glutamine transaminase K activity in the chick embryo at hatching correlates with maturation of astrocytes. Glutamine transaminase K may be involved in glutamine cycling in astrocytes. Glutamine transaminase K appears to be a major cysteine S-conjugate beta-lyase of the brain and may play a role in the neurotoxicity associated with exposure to dichloroacetylene and perhaps to other toxins.

Amidohydrolases↗
PubMed2006

Neural induction: 10 years on since the 'default model'.

Neural induction is the process by which embryonic cells in the ectoderm make a decision to acquire a neural fate (to form the neural plate) rather than give rise to other structures such as epidermis or mesoderm. An influential model proposed a decade ago, the 'default model', postulated that ectodermal cells will become neurons if they receive no signals at all, but that this is normally inhibited in prospective epidermal cells by the action of bone morphogenetic proteins. Recent results now reveal considerable more complexity and emphasis is shifting from intercellular signalling factors to trying to understand the regulation of expression of key genes within the nucleus.

Animals↗