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At least 1,243 records · Page 69Linked to original sources
PubMed1998

Cyclic AMP-dependent protein kinase (PKA) gene expression is developmentally regulated in fetal lung.

We characterized the ontogeny of cAMP-dependent protein kinase (PKA) enzymatic activity and PKA subunit mRNA expression in developing lung. The lungs of fetal Sprague-Dawley rat pups were removed after 16, 18, or 20 days of gestation and at term. PKA activity was greatest in the 18- and 20-day gestation lungs. Tissue cAMP levels were lowest in the 16-day lungs and increased with lung maturity. We were able to detect only low levels of mRNA for the C beta subunit of PKA by northern blot analysis of total lung RNA and we were able to detect mRNA for the RI beta and RII beta subunits only by RT-PCR. Therefore, we limited our analysis of PKA subunit mRNA levels to those for C alpha, RI alpha and RII alpha. The mRNA levels for C alpha, were highest in the 16-day lung, decreased at 18 and 20 days, were lower in the newborn and lowest in the adult lung. RI alpha mRNA levels were also highest at 16 days and lowest in the adult lung. However, RII alpha mRNA levels were similar in the 18-day, 20-day and newborn lungs. Dexamethasone treatment of fetal lung explants resulted in a small decrease in RI alpha mRNA levels but was not associated with a change in PKA activity. We conclude that PKA activity and PKA subunit mRNA expression are developmentally regulated in fetal lung. Such regulation results in optimal PKA activity at the time of type II alveolar cell differentiation, presumably in preparation for air breathing. The absence of an effect of glucocorticoid on PKA activity suggests that glucocorticoids are not responsible for the increase in PKA activity which accompanies this critical time in lung maturation.

Animals↗
PubMed1988

Hybrid insulin genes reveal a developmental lineage for pancreatic endocrine cells and imply a relationship with neurons.

Insulin appears in the developing mouse pancreas at embryonic day 12 (e12). Transgenic mice harboring three distinct hybrid genes utilizing insulin gene regulatory information first express the transgene product two days earlier, at e10, in a few cells of the pancreatic bud. Throughout development and postnatal life, all of the insulin-producing (beta) cells coexpress the hybrid insulin gene. In addition, islet cells containing glucagon, somatostatin, pancreatic polypeptide, and the neuronal enzyme tyrosine hydroxylase coexpress the transgene when they first arise. Similarly, coexpression of these normally distinct islet cell markers occurs during differentiation of the four endocrine cell types. The transgene product also appears transiently during embryogenesis in cells of the neural tube and in neural crest. The results suggest a common precursor for the endocrine cells of the pancreas. Moreover, they imply a relationship between neural and pancreatic endocrine tissue.

Animals↗
PubMed1990

Structural analysis of the Hox-3.1 transcription unit and the Hox-3.2--Hox-3.1 intergenic region.

The mouse Hox gene family is a set of mammalian homeobox genes that may represent developmental control genes. Complete information about the primary structure of these genes is a prerequisite for a systematic analysis of the mechanisms that determine their complex tempero-spatial expression patterns. In this report we describe the complete sequence of the Hox-3.1 locus and provide evidence for several closely spaced transcriptional start sites. Sequence analysis of the 5' region of the Hox-3.1 gene extending to its nearest upstream neighbor, Hox-3.2, allowed us to identify sequences known to be capable of interactions with transcription factors. Several of these sequence motifs are similar to cis-regulatory elements found in the regulatory regions of other known developmentally regulated genes.

Amino Acid Sequence↗
PubMed2006

Gene expression and developmental competence of bovine embryos produced in vitro with different serum concentrations.

The objective of this study was to determine the developmental rates and relative abundance of Hsp 70.1 and Glut-1 transcripts in in vivo- and in vitro-produced (IVP) bovine embryos in media supplemented with bovine serum albumin (BSA) or different oestrous cow serum concentrations. In experiment 1, in vitro maturation and culture media were supplemented with 0.4% BSA or 1, 5, 10 or 20% of oestrous cow serum (ECS). The analysis of the expression of Hsp 70.1 and Glut-1 was carried out in individual days 7 and 8 embryos by a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay. In experiment 2, in vivo-produced morulae were collected on day 7 of the oestrous cycle and employed for the comparison of the relative abundances of Hsp 70.1 and Glut-1 transcripts with IVP morulae produced using two protein sources (10% ECS or 0.4% BSA). No differences were observed in cleavage rate among groups, but blastocyst formation (27%) and hatching rates (78%) were significantly higher in IVP embryos produced with 20% ECS than the other groups (p<0.05). No significant differences were observed in the relative abundances of Hsp 70.1 and Glut-1 mRNA in days 7 and 8 blastocysts expanded blastocysts between groups. The abundances of mRNA for those genes were similar between IVP and in vivo-produced morulae. In spite of the alterations observed in embryonic development, the presence of serum at distinct concentrations did not appear to alter the relative abundance profiles of Hsp 70.1 and Glut-1 compared with controls or the BSA supplementation to the IVP media.

Animals↗
PubMed1996

Light-dependent developmental control of rbcS gene expression in epidermal cells of maize leaves.

Regulatory elements of the maize rbcS-m3 gene (a member of the family of genes encoding the small subunit of ribulose bisphosphate carboxylase) that are sufficient for expression of the beta-glucuronidase (gusA) gene in photosynthetic tissue lead to relatively weak expression of the reporter gene in epidermal cells of green maize leaves when delivered by ballistic gene transfer methods. However, epidermal cells of white, immature segments of maize leaf bases express the same reporter gene strongly. Morphologically, these epidermal cells look undifferentiated and are uniform in size and shape. When cultured for seven days on Murashige-Skoog medium [18], exised leaf base segments expand two-to threefold, and epidermal and guard cells differentiate and mature, regardless of whether or not the tissue is illuminated. Epidermal cells that differentiate in darkness continue to have the capacity to express the rbcS-m3::gusA reporter gene strongly. However, if the leaf base segments are illuminated after four to five days of expansion in darkness, but not before, these more mature epidermal cells are largely unable to express the same gene. That is, they acquire the characteristics of epidermal cells of green maize leaves with regard to expressing the rbcS-m3 reporter gene after undergoing a developmental program (in light or darkness) in vitro and after being exposed to light. White light but not red is effective. Suppression of expression in maize epidermal cells requires different rbcS-m3 sequences than in mesophyll cells [31].

Chloroplasts↗
PubMed1998

Retinoid X receptor-gamma gene expression is developmentally regulated in the embryonic rodent peripheral nervous system.

The retinoid X receptor-gamma (RXRgamma) is a transcription factor that belongs to the thyroid hormone/retinoid family of nuclear receptors. Previous studies have shown that RXRgamma is expressed in the developing peripheral nervous system (PNS) of chick embryos, but such expression has not been reported previously in rodent embryos. Indeed, the pattern of RXRgamma expression appears to be different between avian and rodent species. Using in situ hybridisation and northern blot experiments we show that RXRgamma is expressed in elements of the PNS in rat and mouse embryos and in postnatal rats. However, unlike the chick, where RXRgamma is expressed from the onset of neural crest migration, rat RXRgamma expression in the dorsal root ganglia and trigeminal ganglia was detectable at 14.5 days post coitum (dpc), but not at 13, 12, or 11 dpc. These data suggest that RXRgamma may have a role in the dorsal root ganglia and trigeminal ganglia of late embryos, and that this could be evolutionarily conserved between chick and rodent. On the other hand, rat RXRgamma transcripts in the facio-acoustic (VII-VIII) ganglion were detectable at 11 dpc in neural crest cells condensing to form this ganglion. We discuss the possible significance of the timing of RXRgamma expression in the developing PNS and suggest that closer examination of the structure and function of the PNS of RXRgamma null mutant mice would be of interest.

Animals↗
PubMed1996

Molecular cloning and characterization of a novel form of neuropeptide gene as a developmentally regulated molecule.

To examine the molecular basis controlling neuronal differentiation, subtraction library construction and differential screening were used to identify cDNAs whose mRNA levels are regulated in mouse NS20Y cells by dibutyryl cyclic AMP treatment. One of them, N27K, whose mRNA increases transiently during both neuronal differentiation in NS20Y cells and development in mouse brain. The deduced amino acid sequence of N27K comprises 212 amino acid residues and is a novel form of a precursor protein for a new neuropeptide nociceptin/orphanin FQ, which we independently cloned as N23K. That is, the putative protein encoded by N27K is 25 amino acids longer than that encoded by N23K. Using an antibody against a C-terminal peptide of the N27K protein that recognizes a 27-kDa protein in Western blot analysis, a punctate structure in the perinuclear region and areas near the tip of neurites is visualized in neurally differentiating NS20Y cells. The time of maximal expression correlates with periods of neurite extension, and expression decreases as the neuritic network develops. Immunohistochemistry of tissue sections of the mouse central nervous system revealed that reactivity for the anti-N27K protein antibody can detected in early generated neurons at embryonic day 14, in virtually all immature neurons at postnatal day 1, and in subsets of neurons of discrete brain regions such as the hypothalamus and spinal cord in adults. This remarkable redistribution suggests that N27K may be involved in a process in neurite outgrowth and nervous system development.

Amino Acid Sequence↗
PubMed2002

Calbindin-d(28k): a marker of recurrence for medulloblastomas.

BACKGROUND: The expression of the Ca(2+)-binding protein calbindin-D(28k) was analyzed in medulloblastomas in relation to clinical features and other biologic markers related to cell proliferation, differentiation, p53, and cerebellar developmental regulated gene expression. METHODS: Immunohistochemistry was carried out on histologic slides from a first retrospective series of 29 nonmetastatic and 10 metastatic medulloblastoma formalin-fixed, paraffin-embedded tissues, using specific antibodies against calbindin-D(28k), calretinin, alpha-parvalbumin and beta-parvalbumin, and S100 proteins. Informed consent was obtained from the subjects and/or guardians. Other biologic markers for differentiation, cell proliferation, the expression of the p53 tumor suppressor gene protein, and cerebellar developmental regulated genes were similarly investigated. A second series of 16 medulloblastomas from young patients (younger than 15 years) was added in order to validate the results obtained in the first series. RESULTS: Of all the markers investigated, only calbindin-D(28k) was significantly associated with prognosis. Survival and remission (i.e. recurrence free) time analysis performed on all the cases (n = 55) confirmed a high risk of death (P = 0.004) and recurrence (P = 0.003) associated with calbindin-positivity. As calbindin-positivity was predominantly observed in tumors from young patients, the authors confirmed its prognostic value in the subgroup of patients younger than 15 years (n = 37). Cox regression analysis showed a significant and independent prognostic value for calbindin expression and, to a lesser extent, the type of surgery (total or subtotal). Three risk groups were thus identified, distinguishing among the cases characterized by a total resection and calbindin-negativity (good prognosis), by a subtotal resection and calbindin-negativity (intermediary), and by calbindin-positivity (bad prognosis). CONCLUSIONS: The current study suggests that calbindin-positive medulloblastomas represent a subclass of aggressive tumors more frequently seen in younger patients.

Adolescent↗
PubMed2005

In vitro maturation of erythroid progenitors from human umbilical cord blood and patterns of globin gene expression: serum from different developmental stage plays important roles in liquid culture.

To investigate the maturation of neonatal erythrocytes and kinetics of globin expression, we induced CD34(+) cells purified from human umbilical cord blood to erythroid differentiation in different suspension culture systems containing human cord serum (CHS) and adult serum (AHS), respectively. The zeta- to alpha-globin switching and the epsilon- to gamma-globin switching were observed in CHS(+) cultures but not in AHS(+) cultures. A reduced proportion of F cell and two day postponed cell enucleation in AHS(+) cultures compared with in CHS(+) cultures was also found. However, predominant gamma-globin expression compared with epsilon- and beta-globin was always observed from days 5 in either CHS(+) or AHS(+) cultures. Our data showed that neonatal erythrocytes in CHS(+) cultures maintained their fetal characteristics which differed from their counterpart from adult. Serum from different developmental stage significantly affected the maturation and globin expression pattern of cultured neonatal erythrocytes. Obviously, some uncertain serum components play important roles in cultures, but they are not enough to fundamentally change the developmentally specific globin gene transcription program, suggesting that this program is mainly controlled by determinants within the erythroid progenitors.

Base Sequence↗
PubMed2003

Yin Yang 1, a vertebrate polycomb group gene, regulates antero-posterior neural patterning.

Polycomb group (PcG) genes are required for the stable repression of the homeotic genes and other developmentally regulated genes. Yin Yang 1 (YY1), a vertebrate homolog of the Drosophila PcG pleiohomeotic (Pho), is a multifunctional protein that can act as a repressor or activator of transcription. Xenopus YY1 (XYY1) protein was localized in the central nervous system (CNS), particularly anterior neural tube of tailbud stage embryos. To elucidate the role of endogenous XYY1, loss-of-function studies were performed using XYY1 antisense morpholino oligonucleotide (XYY1 MO). Inhibition of XYY1 function resulted in embryos with antero-posterior axial patterning defects and reduction of head structures. XYY1 MO also reduced the expression of En2, a midbrain/hindbrain junction marker, which was rescued by co-injection of XYY1 mRNA. However, XYY1 MO-injection did not affect the expression of HoxB9, a spinal cord marker. These results suggest that YY1 controls antero-posterior patterning of the CNS during Xenopus embryonic development.

Animals↗
PubMed1995

In vivo functional analysis of the mouse estrogen receptor gene promoter: a transgenic mouse model to study tissue-specific and developmental regulation of estrogen receptor gene transcription.

Understanding the molecular and morphological basis of estrogen responsiveness in the various tissues and organs that make up an adult organism and its onset during ontogenesis requires identification of the genetic controls that determine timed expression of the estrogen receptor (ER) gene in multiple cell types. With this goal in mind, we describe here the results of the functional analysis of the mouse (m) ER gene promoter, carried out in vivo in transgenic mice. The mER gene promoter was cloned and spliced to the coding sequence of the bacterial lacZ gene (fused to the nuclear localization signal of SV40 large T: nls-beta-GAL) and then stably reintegrated into the genome of mice. Analysis of beta-GAL mRNA and protein expression in multiple organs of both female and male transgenic animals was then performed. Results show that the transgenic mER promoter, much like the endogenous one, is active in several organs and tissues of adult female and male mice. The first 0.4 kilobases of 5'-flanking DNA (up to -364) are sufficient to direct widespread expression of the transgene in mouse organs. This indicates that genetic elements functional in various cell types are included in this segment. Furthermore, the first exon and intron of the mER gene are necessary to achieve sexually dimorphic expression of the transgene in neurons located at specific sites within the central nervous system. These mER promoter transgenic mice will be useful in mapping estrogen- responsive cell types under different physiological and pathological conditions in vivo, in defining ontogenesis of estrogen action in the mouse, and in studying the mechanisms that regulate ER gene transcription.

Animals↗
PubMed1999

Axial variation in the threespine stickleback: relationship to Hox gene expression.

Despite mounting evidence that key developmental regulator genes are involved in significant macroevolutionary changes, there have been few studies demonstrating the functional significance of variation in such genes for the generation of population-level variation. In this study we examined and compared the expression domains of three Hox gene homeobox sequences in embryos derived from two morphologically distinct populations of the threespine stickleback, Gasterosteus aculeatus. We found within-population variation in the location of anterior limits, particularly in more 5' Hox genes whose anterior expression domains showed graded distributions of transcripts over several somites. However, despite considerable and statistically significant differences in the anteroposterior pattern of the axial and median skeletons between the two stickleback populations, this phenotypic variation was not found to be correlated with any of the variation in Hox gene expression. The possible functional significance of the combinatorial Hox code in fish species is discussed with respect to the buffering of development in fluctuating environments, and it is argued that population and quantitative genetic perspectives should also be taken into account in considering the function and evolution of Hox genes.

Animals↗
PubMed1994

Developmental regulation of gene expression for the MPTP delta isoforms in the central nervous system and the immune system.

MPTP delta is a murine transmembrane protein tyrosine phosphatase which has three isoforms, types A-C, differing in the structure of the extracellular regions. In this study, we examined MPTP delta isoform expression in the brain and the immune system at discrete developmental or differentiation stages. RT-PCR analysis demonstrated that another isoform, type D, is transcribed from the MPTP delta gene. In the brain, only type D was expressed until postnatal day 7 (P7), but after P14, all four isoforms were detected. In contrast, the spleen, thymus and all the hematopoietic cell lines examined express only types B and C isoforms. An in situ hybridization study showed that MPTP delta mRNA is diffusely expressed throughout the spleen, but its expression in the thymus is restricted to the medullary region.

Animals↗
PubMed1996

Characterization of three heat-shock-protein genes and their developmental regulation during somatic embryogenesis in white spruce [Picea glauca (Moench) Voss].

Three cDNAs (PgEMB22, 27 and 29) predicted to encode low-molecular-weight (LMW) heat-shock proteins (HSPs) were cloned and characterized from white spruce [Picea glauca (Moench) Voss] somatic embryo tissues by differentially screening a cotyledonary embryo cDNA library. Clone PgEMB22 is predicted to encode a putative mitochondria-localized LMW HSP, and PgEMB27 and 29 are predicted to encode different cytoplasmic class II LMW HSPs, although they share 84.7% identity within DNA coding regions and 83.0% identity for predicted proteins. They are developmentally regulated during somatic embryo development and subsequent embryo germination, in addition they show strong response to heat-shock stress. Transcripts of the two kinds of hsp genes could be detected in embryogenic tissues before induction of embryo maturation, but subsequently increased, being most abundant at late embryo stages. Gene expression levels were very low or not detectable in germinated plantlets or needle tissues from older plants. Abscisic acid and polyethylene glycol, stimulators for spruce embryo maturation, could also induce the hsp genes.

Abscisic Acid↗
PubMed1993

Six members of the mouse forkhead gene family are developmentally regulated.

The 110-aa forkhead domain defines a class of transcription factors that have been shown to be developmentally regulated in Drosophila melanogaster and Xenopus laevis. The forkhead domain is necessary and sufficient for target DNA binding as shown for the rat hepatic nuclear factor 3 (HNF3) gene family. We have cloned six forkhead gene family members from a mouse genomic library in addition to the mouse equivalents of the genes for HNF3 alpha, -beta, and -gamma. The six genes, termed fkh-1 to fkh-6, share a high degree of similarity with the Drosophila forkhead gene, having 57-67% amino acid identity within the forkhead domain. fkh-1 seems to be the mammalian homologue of the Drosophila FD1 gene, as the sequences are 86% identical. fkh-1 to fkh-6 show distinct spatial patterns of expression in adult tissues and are expressed during embryogenesis.

Amino Acid Sequence↗
PubMed2000

Effects of Polycomb group mutations on the expression of Ultrabithorax in the Drosophila visceral mesoderm.

The Polycomb group (PcG) genes encode repressors of many developmental regulatory genes including homeotic genes and are known to act by modifying chromatin structure through complex formation. We describe how Ultrabithorax (Ubx) expression is affected by the PcG mutants in the visceral mesoderm. Mutant embryos of the genes extra sex combs (esc), Polycomb (Pc), additional sex combs (Asx) and pleiohomeotic (pho) were examined. In each mutation, Ubx was ectopically expressed outside of their normal domains along the anterior-posterior axis in the visceral mesoderm, which is consistent with the effect of PcG proteins repressing the homeotic genes in other tissues. All of these four PcG mutations exhibit complete or partial lack of midgut constriction. However, two thirds of esc mutant embryos did not show Ubx expression in parasegment 7 (PS7). Even in the embryos showing ectopic Ubx expression, the level of Ubx expression in the PcG mutations was weaker than that in normal embryos. We suggest that in PcG mutations the ectopic Ubx expression is caused by lack of PcG repressor proteins, while the weaker or lack of Ubx expression is due to the repression of Ubx by Abd-B protein which is ectopically expressed in PcG mutations as well.

Animals↗