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Results for “Developmental programming”

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PubMed1999

Short communication: developmental control of Xa21-mediated disease resistance in rice.

The rice resistance gene Xa21 confers resistance against the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo). The molecular genetic mechanism controlling the integration of the Xa21-mediated disease resistance response with the developmental program in rice is under study in this model system. Reproducible means of infecting plants at certain developmental stages were designed based on the timing of full expansion of the leaf. Xa21-resistance progressively increases from the susceptible juvenile leaf 2 stage through later stages, with 100% resistance at the adult leaf 9/10 stage. We found that Xa21 expression is independent of plant developmental stage, infection with Xoo, or wounding. Expression of the Xa21 gene transcript is not correlated with expression of Xa21 disease resistance indicating that the developmental regulation of Xa21-resistance is either controlled post-transcriptionally or by other factors.

Gene Expression↗

PubMedDate not supplied

Use of biological markers in occupational health research and practice.

The promise of biological markers in occupational health research and practice has been described in the scientific literature. The current generation of biological markers has the potential to allow for the earlier detection of disease, for the reduction of misclassification of exposure and outcome, for heightened understanding of mechanisms and etiologic pathways, and for the designation of groups at risk. What is necessary now is a strategy for realizing this potential. The elements of such as a strategy may include the following: (1) a program to validate biomarkers, (2) increased utilization of valid biomarkers in etiologic and prevention research, and (3) developmental programs to encourage interdisciplinary collaboration and train molecular epidemiologists. A framework for linking biomarkers and epidemiologic study designs has evolved during the past 5 yr. For this progress to continue, it is important that discussion about biomarkers reflect a specificity with regard to both the type of marker and the use for which it is intended.

Biomarkers↗

PubMed2005

Rice plant development: from zygote to spikelet.

Rice is becoming a model plant in monocotyledons and a model cereal crop. For better understanding of the rice plant, it is essential to elucidate the developmental programs of the life cycle. To date, several attempts have been made in rice to categorize the developmental processes of some organs into substages. These studies are based exclusively on the morphological and anatomical viewpoints. Recent advancement in genetics and molecular biology has given us new aspects of developmental processes. In this review, we first describe the phasic development of the rice plant, and then describe in detail the developmental courses of major organs, leaf, root and spikelet, and specific organs/tissues. Also, for the facility of future studies, we propose a staging system for each organ.

Flowers↗

PubMed2005

Systematic spatial analysis of gene expression during wheat caryopsis development.

The cereal caryopsis is a complex tissue in which maternal and endosperm tissues follow distinct but coordinated developmental programs. Because of the hexaploid genome in wheat (Triticum aestivum), the identification of genes involved in key developmental processes by genetic approaches has been difficult. To bypass this limitation, we surveyed 888 genes that are expressed during caryopsis development using a novel high-throughput mRNA in situ hybridization method. This survey revealed novel distinct spatial expression patterns that either reflected the ontogeny of the developing caryopsis or indicated specialized cellular functions. We have identified both known and novel genes whose expression is cell cycle-dependent. We have identified the crease region as important in setting up the developmental patterning, because the transition from proliferation to differentiation spreads from this region to the rest of the endosperm. A comparison of this set of genes with the rice (Oryza sativa) genome shows that approximately two-thirds have rice counterparts but also suggests considerable divergence with regard to proteins involved in grain filling. We found that the wheat genes had significant homology with 350 Arabidopsis thaliana genes. At least 25 of these are already known to be essential for seed development in Arabidopsis, but many others remain to be characterized.

Cell Cycle↗

PubMed1998

Developmental regulation of a cyclin-dependent kinase inhibitor controls postembryonic cell cycle progression in Caenorhabditis elegans.

C. elegans cki-1 encodes a member of the CIP/KIP family of cyclin-dependent kinase inhibitors, and functions to link postembryonic developmental programs to cell cycle progression. The expression pattern of cki-1::GFP suggests that cki-1 is developmentally regulated in blast cells coincident with G1, and in differentiating cells. Ectopic expression of CKI-1 can prematurely arrest cells in G1, while reducing cki-1 activity by RNA-mediated interference (RNAi) causes extra larval cell divisions, suggesting a role for cki-1 in the developmental control of G1/S. cki-1 activity is required for the suspension of cell cycling that occurs in dauer larvae and starved L1 larvae in response to environmental signals. In vulva precursor cells (VPCs), a pathway of heterochronic genes acts via cki-1 to maintain VPCs in G1 during the L2 stage.

Animals↗

PubMed1991

Heat shock and thermotolerance in plant and animal embryogenesis.

Although the strategies of early embryogenesis differ greatly among multicellular eukaryotes, there are certain parallels in structure, form, and function that cross even kingdom lines: the extreme heat sensitivity of zygotes and very early embryos, followed by the acquisition of thermotolerance during subsequent development, is one such parallel. The heat sensitivity may be so extreme that even moderate increases in temperature result in lethality (generally associated with the earliest phases of embryogenesis), or the effects may be less severe, resulting in defects in development but not in lethality. Mechanistically, and molecularly, these two forms of thermosensitivity appear to have different origins. On the one hand, outright lethality appears to result from an inability to induce heat shock genes and proteins; on the other hand, heat-induced developmental defects appear to result from an alteration in expression of non-heat shock genes and from a delay in the overall developmental program that generally accompanies the cell's response to heat shock. This review is focused on the developmental regulation of the heat shock response during early embryogenesis and on the impact of this regulation on the development of both animal and plant embryos. The two basic issues that we address here are (i) the expression of heat shock genes in the absence of heat shock during embryogenesis and (ii) the expression (or lack of expression) of heat shock genes after deliberate exposure of the embryos to heat shock and the consequences of this expression on its subsequent survival and development.

Animals↗

PubMed1990

Tissue-specific distribution and developmental regulation of M and B creatine kinase mRNAs.

To characterize the tissue-specific distribution and developmentally regulated expression of M and B creatine kinase mRNA in rats, total cellular RNA was isolated from adult rat tissues and from skeletal muscle, heart, brain and intestine at selected stages of development. Northern blots were prepared and hybridized with M and B subunit-specific probes derived from the 3'-untranslated region. M creatine kinase mRNA was expressed abundantly in heart and skeletal muscle, and less abundantly in lung. B creatine kinase mRNA was found in all tissues examined except liver and was abundant in brain, heart and intestine. The developmentally regulated expression of M and B creatine kinase mRNA was determined in skeletal muscle, heart, brain and intestine. The developmental program of B creatine kinase mRNA was different for each tissue examined. During development, M creatine kinase mRNA was up-regulated in both heart and skeletal muscle with a different regulatory program. This resulted in replacement of B mRNA by M mRNA as the predominant species at an earlier developmental stage in heart when compared to skeletal muscle.

Animals↗

PubMed2006

Programming of GnRH feedback controls timing puberty and adult reproductive activity.

The timing of puberty generally differs between sexes, and this may be due to sex differences in the organization of steroid feedback systems. We propose that the reproductive neuroendocrine default sex is female. If the individual is male, the feedback control of GnRH secretion is programmed early in development, and the pubertal GnRH rise is either advanced or delayed depending upon species. This developmental programming is by androgens. Early programming also reorganizes adult reproductive neuroendocrine function to change a pattern of cyclic gamete release (periodic ovulations) requiring multiple feedback systems to that of a continuous one (spermatogenesis) requiring only the negative feedback control. The multiple feedback systems underlying the complex ovulatory cycle are innate, and in the male the unnecessary feedbacks are abolished or rendered less sensitive during development by the estrogenic, as well as the androgenic metabolites of testosterone.

Animals↗

PubMed2005

Functions and mechanisms of retrograde neurotrophin signalling.

Neuronal connections are established and refined through a series of developmental programs that involve axon and dendrite specification, process growth, target innervation, cell death and synaptogenesis. Many of these developmental events are regulated by target-derived neurotrophins and their receptors, which signal retrogradely over long distances from distal-most axons to neuronal cell bodies. Recent work has established many of the cellular and molecular events that underlie retrograde signalling and the importance of these events for both development and maintenance of proper neural connectivity.

Animals↗

PubMed1987

Superinduction of the Dictyostelium discoideum cell surface cAMP receptor by pulses of cAMP.

Extracellular cAMP plays a crucial role in regulating the developmental program of Dictyostelium discoideum, functioning as a chemotactic agent, as well as a signal that regulates expression of developmentally expressed genes. These activities appear to be mediated by a cell-surface receptor for cAMP. We have studied the regulation of this receptor in cells developed in starved suspension cultures exposed to 50 nM pulses of cAMP every 6 min. cAMP-pulsed cells display roughly 10-fold higher cAMP receptor levels than cells that developed on filters or that were starved in suspension without cAMP pulses. Based on saturation binding analysis, the superinduced binding activity represents an increase in receptor number, while receptor affinity for cAMP is unaffected. Photoaffinity labeling of superinduced cells results in specific labeling of the same molecules that are labeled in starved cells. This increased cAMP binding activity was also detected in membrane preparations from cAMP-pulsed cells. These results provide evidence for an unusual mode of receptor regulation: autogenous induction of the receptor by its ligand.

Affinity Labels↗

PubMed1993

Two transmembrane signaling mechanisms control expression of the cAMP receptor gene CAR1 during Dictyostelium development.

Dictyostelium discoideum is among the best characterized organisms for the study of receptor/guanine nucleotide binding protein-mediated control of differentiation. Dictyostelium grow unicellularly but form fully differentiated multicellular organisms through a developmental program regulated by secreted cAMP activating specific cell-surface receptors. Dictyostelium respond differentially to cAMP at different developmental stages. During early development, expression of certain genes is induced by low-level oscillations of extracellular cAMP. Later, continuous, high cAMP concentrations will promote expression of specific genes in multicellular structures. Here, we show that the cAMP receptor gene CAR1, which is essential for development, utilizes two promoters that are activated at distinct stages of development and respond to different extracellular cAMP conditions. One promoter is active with low-level oscillations of cAMP; exposure to high cAMP concentrations will repress this promoter and induce a second promoter. The CAR1 mRNAs are alternatively spliced but encode identical proteins. Thus, through differential sensitivity to its own ligand, cAMP, two promoters and alternative splicing regulate CAR1 expression during Dictyostelium development.

Alternative Splicing↗

PubMed1994

Pre- and postnatal ontogeny of aromatase cytochrome P450 messenger ribonucleic acid expression in the male rat brain studied by in situ hybridization.

A central step in the development and sexual differentiation of the brain is the intraneuronal conversion of testosterone to estrogen. This conversion is catalyzed by an enzyme complex comprised of cytochrome P450 aromatase and the ubiquitous NADPH-dependent cytochrome P450 reductase. Brain aromatase activity is developmentally regulated and expressed only in specific hypothalamic and limbic structures. To determine whether developmental change in aromatase activity are the result of differential regulation of aromatase gene expression, we designed two specific oligonucleotides complementary to a 5'-region or to the heme-binding region of the rat aromatase complementary DNA. Relative amounts of messenger RNA (mRNA) encoding aromatase cytochrome P450 were examined on cryostat sections from male fetuses and offspring of time-pregnant Long-Evans rats using the in situ hybridization technique. On gestational day (GD) 16 (GD 1 = 24 h after mating), aromatase-specific mRNA was detected in the preoptic/hypothalamic area. On GD18 and GD20, aromatase mRNA expression was more abundant and more widespread. High levels of mRNA were detected in the medical preoptic nucleus, the sexually dimorphic nucleus of the preoptic area, the bed nucleus of stria terminalis, and the medial amygdala. Lower levels were found in the periventricular preoptic nucleus and the ventromedial hypothalamic nucleus. On postnatal day (PN) 2 and throughout further development (PN6, PN15, and adult), aromatase mRNA decreased to much lower levels in the preoptic area, but remained high in the bed nucleus of stria terminalis and amygdala. An intermediate situation, i.e. transient expression with a peak around birth, was observed for aromatase mRNA levels in the ventromedial hypothalamic nucleus. Interestingly, during early postnatal development, specific aromatase mRNA was also detected in the hippocampal formation as well as in the subfornical organ. In summary, these results demonstrate that the low quantities of aromatase transcripts in the developing rat brain can be detected by means of in situ hybridization. Depending on the particular region examined, aromatase expression appears to be subjected to different developmental programs. As the expression of aromatase mRNA parallels the results obtained from activity assays, it is likely that developmental changes in aromatase activity are the result of regulation of aromatase gene expression.

Animals↗

PubMed2004

Identification and molecular characterization of novel anther-specific genes in Oryza sativa L. by using cDNA microarray.

The complicated genetic pathway regulates the developmental programs of male reproductive organ, anther tissues. To understand these molecular mechanisms, we performed cDNA microarray analyses and in situ hybridization to monitor gene expression patterns during anther development in rice. Microarray analysis of 4,304 cDNA clones revealed that the hybridization signal of 396 cDNA clones (271 non-redundant groups) increased more than six-fold in every stage of the anthers compared with that of leaves. Cluster analysis with the expression data showed that 259 cDNA clones (156 non redundant groups) were specifically or predominantly expressed in anther tissues and were regulated by developmental stage-specific manners in the anther tissues. These co-regulated genes would be important for development of functional anther tissues. Furthermore, we selected several clones for RNA in situ hybridization analysis. From these analyses, we found several novel genes that show temporal and spatial expression patterns during anther development in addition to anther-specific genes reported so far. These results indicate that the genes identified in this experiment are controlled by different programs and are specialized in their developmental and cell types.

Cluster Analysis↗

PubMed2005

[Nutritionnal epigenomics: consequences of unbalanced diets on epigenetics processes of programming during lifespan and between generations].

Epigenetic changes associated with DNA methylation and histone modifications leading to chromatin remodeling and regulation of gene expression underlie the developmental programming of obesity, type 2 diabetes, cardiovascular diseases and metabolic syndrome. This review focuses on converging data supporting the hypothesis that, in addition to "thrifty genotype" inheritance, individuals with obesity, type 2 diabetes, and metabolic syndrome (MetS) with an increased risk of cardiovascular diseases have suffered improper "epigenetic programming" during their fetal/postnatal development due to maternal inadequate nutrition and metabolic disturbances and also during their lifetime, that could even be transmitted to the next generation(s). We highlight the susceptibility of epigenetic mechanisms controlling gene expression to environmental influences due to their inherent malleability, emphasizing the participation of transposable elements and the potential role of imprinted genes during critical time windows in epigenetic programming, from the very beginning of development, throughout life. Increasing our understanding on epigenetic patterns significance and their role in development, evolution and adaptation and on small molecules (nutrients, drugs) that reverse epigenetic (in)activation should provide us with the means to "unlock" silenced (enhanced) genes, and to "convert" the obsolete human thrifty genotype into a "squandering" phenotype.

Adult↗

PubMed2003

Development gene networks and evolution.

Animal development relies on complex programs of gene regulation that are likely to account for a significant fraction of the information carried in genomes. The evolution of these regulatory programs is a major contributor to the diversity of animal forms, yet the architecture of the transcriptional networks that comprise developmental programs is only beginning to come into focus. The sea urchin offers an uncomplicated system in which to study transcriptional regulation and the networks that direct embryogenesis. This review describes the approaches that we are taking towards this problem using the sea urchin embryo and some comparative methods that will eventually lead to a deeper understanding of the evolution of developmental networks.

Animals↗

PubMed1997

The role of elav-like genes, a conserved family encoding RNA-binding proteins, in growth and development.

The elav gene is the prototype for a developmental regulator encoding a tissue-specific RNA-binding protein. The family of elav-like genes includes multiple members that are expressed in the nervous system at different times during development and also one that is expressed in all tissues. The elav-like proteins are proposed to function by binding to specific mRNAs and regulating their expression to control a developmental program. Consistent with this model, the overexpression of some elav-like genes results in an alteration in the developmental fates of some cells. Potential mRNA targets for these proteins have been identified along with functions in alternative RNA processing, cytoplasmic polyadenylation, and mRNA stability. This diversity of post-transcriptional regulatory events may be due to combinatorial interactions with other RNA-binding proteins and multiple effectors of RNA regulation.Copyright 1997 Academic Press Limited

Journal Article↗

PubMed2004

Fez1 is layer-specifically expressed in the adult mouse neocortex.

The mammalian cerebral neocortex occupies the largest area of the cerebral cortex and is cytoarchitectually composed of six layers (I-VI). Recent molecular analysis has begun to reveal the existence of various developmental programs, including the genetic regulation of arealization of the neocortex. Although an increasing number of molecular determinants of the developmental stages of the neocortex have been identified, no genes specifically expressed in the adult neocortex have been identified to date. By global screening using microarrays, combined with systematic in situ hybridization, we identified a zinc-finger type transcription factor, Fez1, which is expressed predominantly in the mouse adult neocortex. No other genes in the neocortex have been shown to date to have their expression with such high specificity. Using two-color in situ hybridization, we show that Fez1 is mainly expressed in cortical layers V and VI, not in gamma-aminobutyric acid neurons but in pyramidal neurons, the projection neurons of the cerebral cortex. Immunohistochemistry also shows that Fez1 is expressed in deep layers of the neocortex. Fez1 will be invaluable not only for the molecular understanding of corticogenesis but also for understanding the physiological functions of the adult neocortex, as well as for the use of its promoter in gene-manipulated animals and in conditional expression systems.

Animals↗

PubMed2005

Biomarker metabolites capturing the metabolite variance present in a rice plant developmental period.

BACKGROUND: This study analyzes metabolomic data from a rice tillering (branching) developmental profile to define a set of biomarker metabolites that reliably captures the metabolite variance of this plant developmental event, and which has potential as a basis for rapid comparative screening of metabolite profiles in relation to change in development, environment, or genotype. Changes in metabolism, and in metabolite profile, occur as a part of, and in response to, developmental events. These changes are influenced by the developmental program, as well as external factors impinging on it. Many samples are needed, however, to characterize quantitative aspects of developmental variation. A biomarker metabolite set could benefit screening of quantitative plant developmental variation by providing some of the advantages of both comprehensive metabolomic studies and focused studies of particular metabolites or pathways. RESULTS: An appropriate set of biomarker metabolites to represent the plant developmental period including the initiation and early growth of rice tillering (branching) was obtained by: (1) determining principal components of the comprehensive metabolomic profile, then (2) identifying clusters of metabolites representing variation in loading on the first three principal components, and finally (3) selecting individual metabolites from these clusters that were known to be common among diverse organisms. The resultant set of 21 biomarker metabolites was reliable (P = 0.001) in capturing 83% of the metabolite variation in development. Furthermore, a subset of the biomarker metabolites was successful (P = 0.05) in correctly predicting metabolite change in response to environment as determined in another rice metabolomics study. CONCLUSION: The ability to define a set of biomarker metabolites that reliably captures the metabolite variance of a plant developmental event was established. The biomarker metabolites are all commonly present in diverse organisms, so studies of their quantitative relationships can provide comparative information concerning metabolite profiles in relation to change in plant development, environment, or genotype.

Amino Acids↗