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Results for “Gene Expression Regulation, Developmental”

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At least 19 recordsLinked to original sources

PubMed1997

Developmental regulation of elastin gene expression.

Developmental regulation of elastin gene expression appears to be exerted primarily at the transcriptional level. Although the elastin gene promoter possesses features of "housekeeping" genes, these characteristics do not preclude transcriptional regulation as shown with a number of other gene promoters of this class. Direct evidence for transcriptional regulation has been obtained by nuclear run-on analysis of nuclei isolated from developing lung and aortic tissues and indirectly through elastin promoter activity in transgenic mice and transient tissue transfections of embryonic lung and aortic tissues. Although several different modulators have been proposed to control the developmental activation of elastin gene expression, only insulin-like growth factor I has been experimentally linked to increased transcription by in vivo studies. This link is specific for aortic smooth muscle cells in which cell cycle control appears intimately associated with elastogenesis. Recent studies suggest that progress in understanding developmental activation of the elastin gene lies in transgenic models and organ transfection assays that assess the direct relevancy of the modulators and cis- and trans-acting factors involved.

Animals↗

PubMed2002

Pem homeobox gene regulatory sequences that direct androgen-dependent developmentally regulated gene expression in different subregions of the epididymis.

The epididymis is a useful model system to understand the mechanisms that govern region-specific gene expression, as many gene products display spatially restricted expression within this organ. However, surprisingly little is known about how this regulation is achieved. Here, we report regulatory sequences from the Pem homeobox gene that drive expression in different subregions of the mouse epididymis in vivo. We found that the 0.3-kb 5'-flanking sequence (region I) from the Pem proximal promoter (Pem Pp) was sufficient to confer androgen-dependent and developmentally regulated expression in the caput region of the epididymis. Expression was restricted to the normal regions of expression of Pem in the caput (segments 2-4), but there was also aberrant expression in the corpus region. This corpus misexpression was extinguished when 0.6 kb of Pem Pp 5'-flanking sequence was included in the transgene, indicating that one or more negative regulatory elements exist between 0.6 and 0.3 kb upstream of the Pem Pp start site (region II). When heterologous sequences were introduced upstream of the Pem Pp, expression was further restricted, mainly to caput segment 3, implying that the Pem Pp has segment-specific regulatory elements. To our knowledge, the regulatory regions we have identified are the shortest so far defined that dictate regionally localized expression in the epididymis in vivo. They may be useful for identifying the factors that regulate region-specific expression in the epididymis, for expressing and conditionally knocking out genes in different subregions of the epididymis, for treating male infertility, and for generating novel methods of male contraception.

Androgens↗

PubMed2002

A gene trap Dissociation insertion line, associated with a RING-H2 finger gene, shows tissue specific and developmental regulated expression of the gene in Arabidopsis.

Real interesting new gene (RING) finger proteins act as E3 ubiquitin-protein ligases and play critical roles in targeting the destruction of proteins of diverse functions in all eukaryotes, ranging from yeast to mammals. Arabidopsis genome contains a large number of genes encoding RING finger proteins. In this report we describe the identification of more than 40 RING-H2 finger proteins that are of small size, not more than 200 amino acids, and contain no other recognizable protein-protein interaction domain(s). We characterize RHA2b, one of these small RING-H2 finger genes. A gene trap line, SGT6304, was identified to contain a Dissociation (Ds) insertion in RHA2b gene. No RHA2b transcript was detected in the homozygous SGT6304 plants. Despite the elimination of RHA2b function, homozygous SGT6304 plants lacked detectable growth or development defects, suggesting functional redundancy of RHA2b with other RING finger genes. Expression of RHA2b was specifically active in vascular tissue and in upper pistil of inflorescence as well as in root tip and shoot apical meristem region. Potential functions of ubiquitin-proteolysis pathway in vascular formation and in fertilization are discussed.

Amino Acid Sequence↗

PubMed2005

EST sequencing and time course microarray hybridizations identify more than 700 Medicago truncatula genes with developmental expression regulation in flowers and pods.

To evaluate the molecular mechanisms during pod and seed formation in legumes, starting with the development of reproductive organs, we constructed two cDNA libraries from developing flowers (MtFLOW) and pods including seeds (MtPOSE) of the model plant Medicago truncatula Gaertner. A total of 2,516 expressed sequence tags (ESTs) clustered into 1,776 nonredundant sequences (2k-set), which were annotated and assigned to functional classes. While about 30% of the ESTs encoded proteins of yet unknown function, typical annotations pointed to seed storage proteins, LTPs and lipoxygenases. The 2k-set was used to upgrade Mt6k-RIT microarrays (Küster et al. in J Biotechnol 108: 95, 2004) to Mt8k versions representing approximately 6,300 nonredundant M. truncatula genes. These were used to perform time course expression profiling studies based on hybridizations of samples that covered eight different developmental stages from flower buds to almost mature pods versus leaves as a common reference. About 180 up- and 70 downregulated genes were typically found for each stage and in total, 782 genes were either twofold up- or downregulated in at least one of the eight stages investigated. Based on this set, a combination of self-organizing map and hierarchical clustering revealed genes displaying expression regulation during characteristic stages of M. truncatula flower and pod development. Amongst those, several genes encoded proteins related to seed metabolism and development including novel regulators and proteins involved in signaling.

Expressed Sequence Tags↗

PubMed1996

Postnatal age at onset of hyperoxic exposure influences developmentally regulated tropoelastin gene expression in the neonatal rat lung.

Upregulation of tropoelastin (TE) gene expression in rat lung interstitial fibroblasts normally occurs during alveolar septation. TE message increases at the end of the first week of life, peaks on days 9-11, and returns to barely detectable levels over the next 7-10 days. Our previous in situ hybridization studies indicated that exposure of pups to > 95% oxygen from 3 to 13 days of age interfered with the increased in TE gene expression in interstitial fibroblasts normally seen during septation. However, when the pups were returned to room air, lung fibroblast TE message levels increased, exceeding levels seen in control lungs during the exposure. In addition, TE message levels remained elevated for a week after levels in control lungs had returned to background. A possible interpretation of these results was that the developmentally regulated increase in TE messenger RNA (mRNA) was downregulated by the hyperoxic exposure but resumed when the pups were returned to a normoxic environment. We report herein the results of a subsequent study conducted to determine whether continued hyperoxic exposure beyond day 13 would further delay the peak in TE mRNA. Rat pups were exposed to 95% O2 from 5 to 17 days of age. TE and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) message levels in lung interstitial fibroblasts were assessed by in situ hybridization. As observed in pups exposed from 3 to 13 days, hyperoxic exposure from days 5 to 17 also extended the period during which TE mRNA levels were elevated. After exposure, TE message levels were 99%, 262%, and 223% of controls on days 19, 21, and 23 respectively. In addition, delaying the exposure 2 days until the pups were 5 days old resulted in an upregulation of TE message, relative to control values, during the hyperoxic exposure. In hyperoxic pups, values for TE message expression were 105%, 152%, 168%, and 144% of control pups on days 9, 11, 13, and 16 respectively. The influence on peak TE message expression of postnatal age at the time of exposure was further explored to verify the results of the 3-13 and 5-17 day exposures. When pups were exposed continuously from 2, 3, 4, 5, or 6 days until 11 days of age, the results of both in situ hybridization and Northern blot analysis confirmed our previous observations, demonstrating that the postnatal age at which hyperoxic exposure is initiated influences TE message expression in the developing lung.

Age Factors↗

PubMed1994

Molecular cloning of cucumber phosphoenolpyruvate carboxykinase and developmental regulation of gene expression.

A cDNA library from RNA of senescing cucumber cotyledons was screened for sequences also expressed in cotyledons during post-germinative growth. One clone encodes ATP-dependent phosphoenolpyruvate carboxykinase (PCK; EC 4.1.1.49), an enzyme of the gluconeogenic pathway. The sequence of a full-length cDNA predicts a polypeptide of 74,397 Da which is 43%, 49% and 57% identical to bacterial, trypanosome and yeast enzymes, respectively. The cDNA was expressed in Escherichia coli and antibodies raised against the resultant protein. The antibody recognises a single polypeptide of ca. 74 kDa, in extracts of cotyledons, leaves and roots. The cucumber genome contains a single pck gene. In the seven-day period after seed imbibition, PCK mRNA and protein steady-state levels increase in amount in cotyledons, peaking at days 2 and 3 respectively, and then decrease. Both accumulate again to a low level in senescing cotyledons. This pattern of gene expression is similar to that of isocitrate lyase (ICL) and malate synthase (MS). When green cotyledons are detached from seedlings and incubated in the dark, ICL and MS mRNAs increase rapidly in amount but PCK mRNA does not. Therefore it seems unlikely that the glyoxylate cycle serves primarily a gluconeogenic role in starved (detached) cotyledons, in contrast to post-germinative and senescing cotyledons where PCK, ICL and MS are coordinately synthesised. While exogenous sucrose greatly represses expression of icl and ms genes in dark-incubated cotyledons, it has a smaller effect on the level of PCK mRNA.

Amino Acid Sequence↗

PubMed1997

Zis: a developmentally regulated gene expressed in juxtaglomerular cells.

Renal juxtaglomerular (JG) cells are specialized myoepithelioid cells located in the afferent arteriole at the entrance to the glomerulus. Their main function and distinctive feature is the synthesis and release of renin, the key hormone-enzyme of the renin-angiotensin system that regulates arterial blood pressure. Despite their relevance to health and disease, not much is known about factors that confer and/or maintain JG cell identity. To identify genes uniquely expressed in JG cells, we used a cell culture model and RNA differential display. JG cells cultured for 2 days express renin and renin mRNA, but after 10 days in culture they no longer contain or release renin and renin mRNA is reduced 700-fold. We report one cDNA differentially expressed in the 2-day JG cell culture that detects a 2.6-kb mRNA expressed at higher levels in newborn than adult kidney. Screening a 2-day culture JG cell cDNA library yielded clones representing differentially spliced transcripts. These cDNAs encode one unique protein (Zis) containing zinc fingers and domains characteristic of splicing factors and RNA binding proteins. Northern blot analysis confirmed Zis mRNA expression in differentiated JG cells, and identified an additional unique 1.5-kb transcript. The Zis transcripts are developmentally regulated in kidney and a number of other organs. The features of the Zis protein and its organ distribution suggest a possible role in regulation of transcription and/or splicing, both important steps for controlling developmentally expressed genes.

Aging↗

PubMed2005

Developmentally regulated gene expression of the small heat shock protein Hsp27 in zebrafish embryos.

Mammalian small heat shock proteins including Hsp27 and alpha-B crystallin are constitutively expressed in various adult and embryonic tissues including skeletal and cardiac muscle. However, the function of these proteins during embryonic development is not understood, and information on their expression during the earliest stages of development is limited. We have recently demonstrated constitutive and stress inducible expression of a homologue of human Hsp27 in adult zebrafish, an important experimental model of vertebrate developmental processes. Here, we assessed the temporospatial dynamics of zebrafish Hsp27 (hsp27) and alpha-B crystallin (cryab) gene expression using reverse-transcriptase PCR (RT-PCR) and hsp27 expression by in situ hybridization. Our results reveal that initial upregulation of hsp27 expression occurs during early gastrulation. Expression of hsp27 is detected transiently in developing myotomes, lens and brain, and more persistently in developing heart. The constitutive expression level of hsp27 in embryos at some stages of development is considerably greater than that observed in unstressed adult tissues. Expression of hsp27 was also observed in all tissues examined in embryos recovering from heat stress. The pattern of expression observed for hsp27 overlaps partially, but not completely, with that reported for other heat shock proteins.

Animals↗

PubMed1997

Developmentally regulated gene expression of all eight metabotropic glutamate receptors in hypothalamic suprachiasmatic and arcuate nuclei--a PCR analysis.

Previous studies have demonstrated the critical role glutamate plays in the hypothalamus, both in the developing and adult brain. The expression of metabotropic glutamate receptor (mGluR) mRNA (mGluR1-8) was studied in the suprachiasmatic (SCN) and arcuate (ARC) nuclei. Using reverse Northern blots and cDNA-PCR, we found that all eight cloned mGluRs were expressed in these brain regions. Most had not previously been detected here. Surprisingly, this included mGluRs that had previously been thought to be restricted to the retina, such as mGluR6. We also detected, cloned, and sequenced a splice variant of mGluR7 (mGluR7b). Developmentally, the age of maximal expression of mGluRs was dependent on the region. For instance, mGluR5 was more strongly expressed in neonatal ARC than in adult, whereas the opposite was true in the SCN. Compared with P10 neonates, mGluR1, R3, R6, R7a, R7b, and R8 showed a greater expression in adult SCN and ARC.

Amino Acid Sequence↗

PubMedDate not supplied

Estrogen modulates developmentally regulated gene expression in the fetal baboon liver.

Although estrogen plays a central integrative role in regulating key aspects of placental and fetal endocrine development in the primate, our understanding of the regulation of maturation of the fetal liver is incomplete. In adults, estrogen modulates several aspects of hepatic function. Therefore, the current study determined whether fetal hepatic gene expression development was modulated by estrogen. mRNA differential display was used to identify genes whose expression was altered in fetal livers obtained on d 165 of gestation (term = d 184) from baboons that were untreated or treated on d 60-164 with the aromatase inhibitor CGS 20267 (2 mg/d; sc), which suppressed estrogen levels in the fetus by >95% (p < 0.01). As confirmed by Northern blot, the mRNA levels (ratio to 18s RNA) of metallothionein I (MT-I), porphobilinogen deaminase (PBG-D), and cytochrome P450 2C8 (CYP 2C8) in the livers of estrogen-deprived fetuses were 5-, 12-, and 3-fold higher (p < 0.05) than respective values of untreated fetuses. Moreover, mRNA levels of MT-I and PBG-D, expressed as a ratio to 18s RNA, were 3-fold and 26-fold higher (p < 0.05) on d 60-100 of gestation than on d 165 and in the adult. In contrast, CYP 2C8 mRNA increased 10-fold between d 100 and 165 and was not further altered in adult liver. Immunohistochemistry confirmed expression of MT-I in hepatocytes. Erythropoietic cells, normally present in the fetal baboon liver on d 100 but not on d 165, were also detected on d 165 in animals treated with the aromatase inhibitor. Thus, upregulation of PBG-D mRNA in estrogen-deprived baboons may reflect prolongation of the erythropoietic role of the fetal liver. In summary, these results indicate that the normal developmental change in MT-I, PBG-D, and CYP 2C8 mRNA expression in baboon fetal liver with advancing gestation are dependent on increased secretion of estrogen into the fetus. We suggest, therefore, that estrogen regulates normal development of the primate fetal liver.

Animals↗

PubMed2000

Developmentally regulated gene expression of Th2 cytokines in the brain.

Given the critical role of cytokines in the regulation of an inflammatory response, we investigated whether certain cytokines are expressed in the brains of normal mice during maturation that could contribute to the immune-privileged nature of the CNS or potentially influence an immune-mediated illness such as experimental allergic encephalomyelitis. The gene expression of IFN gamma (Th1 cytokine) and IL-4 (Th2 cytokine) was analyzed in the brain of several strains of mice. IFN gamma was not detectable. However, IL-4 was present in the brains of neonatal mice, but not adult mice. Resident CNS cells are believed to be the source of the IL-4, because mice deficient in T cells (SCID and RAG2-/-) expressed the IL-4 gene in the CNS. Further analysis indicated that the gene expression of the Th2 cytokine transcription factor, GATA-3, correlated with IL-4 and IL-10 expression in the brain. Since GATA-3-deficient mice have an abnormal CNS, brain-derived Th2 cytokines may play an important role in CNS development, as well as potentially contribute to the immune-privileged nature of the brain.

Age Factors↗

PubMed1996

Developmentally regulated gene expression of thrombomodulin in postimplantation mouse embryos.

Embryonic lethality of thrombomodulin-deficient mice has indicated an essential role for this regulator of blood coagulation in murine development. Here, the embryonic expression pattern of thrombomodulin was defined by surveying beta-galactosidase activity in a mouse strain in which the reporter gene was placed under the regulatory control of the endogenous thrombomodulin promoter via homologous recombination in embryonic stem cells. The murine trophoblast was identified as a previously unrecognized anatomical site where TM expression is conserved between humans and mice and may exert a critical function during postimplantation development. Targeted reporter gene expression in mesodermal precursors of the endothelial cell lineage defined thrombomodulin as an early marker of vascular differentiation. Analysis of the thrombomodulin promoter in differentiating ES cells and in transgenic mice provided evidence for a disparate and cell type-specific gene regulatory control mechanism in the parietal yolk sac. The thrombomodulin promoter as defined in this study will allow the targeting of gene expression to the parietal yolk sac of transgenic mice and the initiation of investigations into the role of parietal endoderm in placental function.

Animals↗

PubMed1998

Cloning of rat vitamin K-dependent gamma-glutamyl carboxylase and developmentally regulated gene expression in postimplantation embryos.

Vitamin K-dependent carboxylase catalyzes the posttranslational modification of glutamate to gamma-carboxyglutamate (Gla) in its substrates, the vitamin K-dependent proteins (VKDPs). This modification is required for the activities of the VKDPs. Recent evidence demonstrates previously unrecognized roles for VKDPs as signaling molecules important in the regulation of cell growth, adhesion, and apoptosis, suggesting developmental functions for VKDPs and hence the carboxylase. The tissue distribution and functions of carboxylase in development are unknown. In this study, we isolated and characterized the full-length cDNA encoding the rat carboxylase and analyzed, at the cellular level, the expression of this gene in rat embryos by in situ hybridization. We demonstrate that the expression of this gene is highly regulated in a developmental and tissue-specific manner. Hepatocytes, the major site of synthesis of VKDPs of blood coagulation, express carboxylase mRNA late in gestation, in contrast to the central nervous system, mesenchymal, and skeletal tissues which express carboxylase mRNA early during rat embryogenesis. The tissue-specific temporal expression of the carboxylase gene during embryogenesis indicates that vitamin K-dependent carboxylation and the formation of Gla is developmentally regulated. These studies suggest that vitamin K-dependent carboxylation is an important modulator of embryonic VKDP function.

Amino Acid Sequence↗

PubMed1995

The Arabidopsis thaliana 4-coumarate:CoA ligase (4CL) gene: stress and developmentally regulated expression and nucleotide sequence of its cDNA.

An Arabidopsis cDNA clone encoding 4-coumarate:CoA ligase (4CL), a key enzyme of phenylpropanoid metabolism, was identified and sequenced. The predicted amino acid sequence is similar to those of other cloned 4CL genes. Southern blot analysis indicated that 4CL is single-copy gene in Arabidopsis. Northern blots showed that 4CL expression was activated early during seedling development. The onset of 4CL expression was correlated with the onset of lignin deposition in cotyledons and roots 2-3 days after germination. The timing of the expression of a parsley 4CL1-GUS fusion in transgenic Arabidopsis seedlings was examined in parallel and was very similar to that of endogenous 4CL. In mature plants, highest 4CL expression was observed in bolting stems, where relatively large amounts of lignin accumulate. Both 4CL and 4CL1-GUS mRNA accumulation was strongly and transiently activated by wounding of mature Arabidopsis leaves. 4CL expression was specifically activated within 6 h after infiltration of Arabidopsis ecotype Columbia leaves with a Pseudomonas syringae pv. maculicola strain harboring the bacterial avirulence gene avrB, which causes in incompatible interaction. The timing of 4CL activation was identical to the previously observed activation of PAL gene expression in this interaction. No activation of 4CL expression was observed in a compatible interaction caused by a Pseudomonas syringae pv. maculicola strain without avrB.

Amino Acid Sequence↗

PubMed1991

Isolation and characterisation of a testis-expressed developmentally regulated gene from the distal inversion of the mouse t-complex.

We differentially screened a pool of mouse testis clones in order to identify genes important in germ cell development. One of the isolated clones was found to be expressed only in the male germ line where it is first detected at around the pachytene spermatocyte stage. This gene maps to a subregion of the t-complex in the distal inversion near, but not within, the tw18 and the th20 deletions. A comparison of the t and wild forms of the gene reveals a high degree of sequence conservation. This gene is associated with a CpG-rich island at its 5' end. It encodes a novel protein with extensive alpha-helical structure indicative of coiled-coil interactions.

Amino Acid Sequence↗

PubMed1989

Myosin light chain enhancer activates muscle-specific, developmentally regulated gene expression in transgenic mice.

The rat myosin light chain (MLC)1/3 gene locus contains a potent muscle-specific enhancer, located downstream of the coding region, greater than 24 kilobases away from the MLC1 transcription start site. To assess the role of this enhancer in the activation of MLC expression during development, transgenic mice were generated carrying multiple copies of a MLC1 promoter-chloramphenicol acetyltransferase (CAT) transcription unit linked to a genomic fragment including the enhancer. CAT expression was detected in four mouse lines, up to 1000-fold higher in skeletal muscles than in other tissues. Activation of endogenous MLC1 transcription in these animals 4 days before birth was reflected in the onset of CAT transgene expression. This study identifies the transcriptional control elements necessary to activate the 21-kilobase MLC1/3 locus at the appropriate fetal stage and indicates that the MLC enhancer is sufficient to induce developmentally regulated expression from the MLC1 promoter exclusively in skeletal muscle cells.

Aging↗

PubMed1995

Protein L-isoaspartyl methyltransferase: developmentally regulated gene expression and protein localization in the central nervous system of aged rat.

We have cloned a cDNA encoding protein L-isoaspartyl methyltransferase (PIMT) and characterized gene expression in the development, maturation, and the aging process of the central nervous system by RNA blot analysis, western blot analysis, and immunohistochemistry. PIMT transcript was detected in rat embryonic brain and showed a linear up-regulation during the maturation of the brain and maintained its level in aged rat brain. Immunoblot analysis also supported a linear increase in the amount of PIMT in the maturation process of rat brains. An immunohistochemical study showed that PIMT is strongly expressed in neurons and weakly but definitively in glial cells and oligodendrocytes. These immunoreactivities significantly increased in some neurons of the hippocampus, cerebral cortex, and the brain stem of aged rat brain. The present results suggest that the expression of PIMT is associated with the amount of racemized/isomerized proteins accumulated during the developmental and aging process of the central nervous system.

Age Factors↗

PubMed1982

Membrane sites regulating developmental gene expression in Dictyostelium discoideum.

Postaggregative gene expression in Dictyostelium discoideum requires cell contact. Polyspecific monovalent antibodies (Fab) prepared from sera raised against membranes of aggregation- and postaggregation-stage cells were used to probe the cell interactions that induce rapid postaggregative synthesis of UDP-glucose pyrophosphorylase. When cells of strain V12M2 were dissociated after 8 hr of development and replated in the presence of immune Fab, both reaggregation and pyrophosphorylase synthesis were blocked. Fab neutralized by incubation with EDTA-high salt extracts of cells developed for 3 hr blocked pyrophosphorylase synthesis but not reaggregation. Therefore, some cell-surface components that regulate pyrophosphorylase synthesis (called E sites) are antigenically distinct from those required for reaggregation. The Fab provides a means to assay E sites during their purification. Addition of 10(-3) M cyclic AMP or cyclic GMP enabled the cells to bypass the blocking of E sites by Fab; pyrophosphorylase was synthesized in the absence of reaggregation. We hypothesize that E sites function by raising the level of intracellular cyclic AMP.

Cell Communication↗