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At least 667 records · Page 37Linked to original sources
PubMed1999

Time course of transient expression of GDNF protein in rat granule cells of the bilateral dentate gyri after unilateral intrahippocampal kainic acid injection.

We examined the time course of expression of glial cell line-derived neurotrophic factor (GDNF) protein in the granule cells of the dentate gyrus following unilateral intrahippocampal injection of kainic acid (KA). Recurrent behavioral seizures were observed approximately 1 h after KA injection, which lasted for 4-6 h. GDNF immunoreactivity began to increase bilaterally in the granule cells within 3 h after KA injection, continued to increase until post-injection day (PID) 4, and returned to the control level by PID 7. The results suggest that the increase of GDNF protein in the granule cells may be ascribable to seizures induced by the KA injection. The increase of GDNF protein might promote survival of the granule cells after the intrahippocampal KA injection.

Animals↗
PubMed1997

Transient expression of alpha-1B adrenoceptor messenger ribonucleic acids in the rat superior cervical ganglion during postnatal development.

We have examined the developmental profile of the alpha-1 and alpha-2 adrenergic receptor messenger ribonucleic acids expression in the rat superior cervical ganglion. The expression of the six messenger ribonucleic acids was studied using reverse transcription-polymerase chain reaction. At four weeks, the dominant messenger ribonucleic acids transcripts in this sympathetic ganglion were alpha-1C, alpha-2A, alpha-2B and alpha-2C. The expression of alpha-1 genes in the superior cervical ganglion appears to be regulated during postnatal development in that two alpha-1 (alpha-1B, alpha-1C) genes were expressed at birth, three, seven and 14 days postnatal but no amplified product for alpha-1B was detected at 28 days and in the aged animals, while the alpha-1C transcript continued to be expressed. No amplified product for alpha-1D was detected in superior cervical ganglion at any of the ages studied. While all three alpha-2 genes were expressed in the superior cervical ganglion at four weeks the dominant alpha-2 messenger ribonucleic acids transcript expressed in the superior cervical ganglion was alpha-2A. This pattern of alpha-2 adrenoceptor gene expression was maintained from birth, throughout development and into old age. These results suggest that the expression of alpha-1 adrenergic receptors in the superior cervical ganglion is regulated developmentally while the expression of alpha-2 genes remains unchanged.

Aging↗
PubMed1999

A new form of synaptic plasticity is transiently expressed in the developing rat visual cortex: a modulatory role for visual experience and brain-derived neurotrophic factor.

Synaptic plasticity has been implicated in the mechanisms contributing to the shaping of the cortical circuits responsible for the transmission of the visual input in the rat primary visual cortex. However, the degree of plasticity of the thalamocortical synapse may change during development, perhaps reflecting the degree of stabilization of the circuitry subserving it. We have chosen the ability of this synapse to be first depressed and then potentiated as a specific indicator of its plasticity. In this study we have investigated how this parameter changes during development and the factors controlling it. Extracellular field potentials in cortical layers 2/3 were evoked by stimulation of the white matter in rat primary visual cortex slices prepared at different postnatal ages. Low-frequency stimulation (900 pulses at 1 Hz) of the white matter was used to induce long-term depression of field potential amplitude, whereas long-term potentiation was evoked by high-frequency stimulation consisting of three trains at 100 Hz. We provide evidence that while it is possible to potentiate previously depressed synapses soon after eye opening (postnatal day 17) this synaptic characteristic decreases rapidly thereafter. The decrease in this form of cortical synaptic plasticity closely matches the stabilization of the cortical circuitry towards an adult pattern of connectivity and function. Depressed cortical synapses cannot be potentiated in normal rats at postnatal 23, but they can be potentiated in rats reared in the dark from postnatal days 17 to 29. Moreover, application of brain-derived neurotrophic factor, known to be expressed in an activity-dependent manner, was able to restore the ability of synapses to be potentiated after long-term depression, thus indicating its important modulatory role in brain development.

Animals↗
PubMed1997

The cDNA cloning and transient expression of a chicken gene encoding cytochrome P-450scc.

A cDNA clone, pcSCC1, isolated from a chicken adrenal gland library showed about 62% nucleotide sequence similarity to those of mammalian and rainbow trout P-450scc cDNAs and was proved to be the clone for chicken P-450scc by the enzymatic activity of converting 25-hydroxycholesterol to pregnenolone demonstrated in the transfected COS-7 cells. Comparison of deduced amino acid sequences shows significant conservation of heme- and steroid-binding domains but little similarity in the putative N-terminal presequence region among chicken, trout and mammals. The chicken cDNA lacks a polyadenylation signal in its 3'-UTR. Sequencing of a 3' end region of the P-450scc gene (CYP11A1) suggests that a region containing the polyadenylation signal is spliced out from the pre-mRNA.

Amino Acid Sequence↗
PubMed1997

The cDNA cloning and transient expression of a chicken gene encoding a follicle-stimulating hormone receptor.

A clone, pcFSHR, containing a 3.1-kb insert was isolated from a cDNA library of chicken ovarian follicles by screening with an RT-PCR-generated cDNA probe for a putative N-terminal half-region of chicken FSH-R. The deduced amino acid sequence of pcFSHR exhibits about 84% identity to those of mammalian FSH-R and about 70% to those of mammalian LH-CG-R. Northern blot analysis for total RNA preparations from several chicken tissues revealed that transcripts detected with pcFSHR were present exclusively in ovary and testis. In a chicken ovary, the transcripts were detected in granulosa but not in theca cells. A radioligand receptor assay for the human 293 cells transfected with an expression vector containing the insert of pcFSHR demonstrated the production of a receptor which showed about 10-fold higher affinity for chicken FSH than for chicken LH. The affinity for chicken FSH was significantly higher than for human FSH. In consistency with the ligand specificity of the receptor, a significantly higher level of intracellular accumulation of cAMP was detected when the transfected cells were treated with chicken FSH than with chicken LH. From these results, we conclude that pcFSHR is a cDNA clone for the chicken FSH-R.

Amino Acid Sequence↗
PubMed1998

Transient expression of a novel Six3-related zebrafish gene during gastrulation and eye formation.

Both the Drosophila homeobox gene sine oculis and its murine homologue Six3 have regulatory functions in eye development. In zebrafish, in addition to two previously reported homologues of murine Six3, we have identified a related gene (six7). Although the deduced Six7 protein shares less than 68% sequence identity with the other known zebrafish Six3-like proteins, the embryonic expression patterns have highly conserved features. The six7 transcripts are first detected in involuting axial mesendoderm and, subsequently, in the overlying neurectoderm from which the forebrain and optic primordia develop. Similar to the two other zebrafish Six3 homologues, the expression boundaries of six7 correspond quite closely with the edges of the optic vesicles. Hence, the partially overlapping expression domains of these three six genes probably contribute to anteroposterior specification and in defining the eye primordia.

Amino Acid Sequence↗
PubMed2001

The CRE/CREB pathway is transiently expressed in thalamic circuit development and contributes to refinement of retinogeniculate axons.

The development of precise connections in the mammalian brain proceeds through refinement of initially diffuse patterns, a process that occurs largely within critical developmental windows. To elucidate the molecular pathways that orchestrate these early periods of circuit remodeling, we have examined the role of a calcium- and cAMP-regulated transcriptional pathway. We show that there is a window of CRE/CREB-mediated gene expression in the developing thalamus, which precedes neocortical expression. In the LGN, this wave of gene expression occurs prior to visual experience, but requires retinal function. Mutant mice with reduced CREB expression show loss of refinement of retinogeniculate projections. These results suggest an important role of the CRE/CREB transcriptional pathway in the coordination of experience-independent circuit remodeling during forebrain development.

Aging↗
PubMed1993

Transient expression of type III collagen by odontoblasts: developmental changes in the distribution of pro-alpha 1(III) and pro-alpha 1(I) collagen mRNAs in dental tissues.

The expression of pro-alpha 1(III) and pro-alpha 1(I) collagen mRNAs in mouse and human dental tissues during tooth development and after its completion was analyzed by in situ hybridization, with use of [35S]-labeled RNA probes. The expression of pro-alpha 1(III) mRNA was also compared to that of the protein product, as localized by immunostaining with polyclonal antibodies to type III collagen and the N-terminal propeptide of type III procollagen. Contrary to many previous reports, our results suggest that odontoblasts express type III collagen. While pro-alpha 1(III) transcripts were less intensely expressed in odontoblasts than pro-alpha 1(I) transcripts, the amounts of both mRNAs increased in odontoblasts with progressing dentin formation, and decreased toward its completion. In contrast to pro-alpha 1(III) mRNA, pro-alpha 1(I) mRNA was still detectable in odontoblasts of fully developed teeth. Type III collagen immunoreactivity was observed in the early predentin, and again in predentin toward the completion of dentinogenesis, when mRNA was no longer detected. Also in the pulp, the protein product, unlike pro-alpha 1(III) mRNA, was relatively strongly expressed. Hence, these immunostaining patterns were inversely related to the expression of pro-alpha 1(III) mRNA, suggesting accumulation of the protein. The mesenchymal cells, when condensed in the region of the future mandibular bone, expressed pro-alpha 1(III) mRNA intensely, whereas osteoblasts expressed pro-alpha 1(I) but not pro-alpha 1(III) transcripts strongly. Cell type- and developmental stage-related differences in the expression of the two mRNAs suggest that type I/type III collagen ratio influences the structure of dental tissues.

Aging↗
PubMed2000

Transient expression of synaptogyrin in the ganglionic eminence of the human fetal brain.

The ganglionic eminence (GE) representing a conspicuous bulb-like elevation of the telencephalic proliferative zone has recently been shown to be involved in the establishment of cortical connections. This study demonstrates the presence of synaptogyrin-immunoreactivity in a large number of cell bodies of the human GE between 12 and 20 weeks of gestation. From the 20th week onwards synaptogyrin expression sharply declines. No immunoreactive structures are detectable in the 23rd week or later. As the GE persists nearly throughout the entire fetal period these results show that its neurochemical features change distinctly in the course of development. The synaptogyrin-immunoreactive GE-cells may form an early corticopedal connection which provides a scaffold for outgrowing cortical axons.

Abortion, Induced↗
PubMed2002

The transient expression of pre-B cell receptors governs B cell development.

Only a subpopulation of relatively large pre-B cells express pre-B cell receptors (preBCR) that can be seen with very sensitive immunofluorescence methods. Inefficient assembly of the multicomponent preBCR coupled with their ligand-induced endocytosis may account for the remarkably low in vivo levels of preBCR expression. Signaling initiated via the preBCR promotes cellular proliferation and RAG-1 and RAG-2 downregulation to interrupt the immunoglobulin V(D)J gene rearrangement process. Silencing of the surrogate light chain genes, VpreB and lambda5, then terminates preBCR expression to permit cell cycle exit, recombinase gene upregulation, and VJ(L) rearrangement by small pre-B cells destined to become B cells.

Animals↗
PubMed1998

A novel lysosome-associated membrane glycoprotein, DC-LAMP, induced upon DC maturation, is transiently expressed in MHC class II compartment.

We have identified a novel lysosome-associated membrane glycoprotein localized on chromosome 3q26.3-q27, DC-LAMP, which is homologous to CD68. DC-LAMP mRNA is present only in lymphoid organs and DC. A specific MAb detects the protein exclusively in interdigitating dendritic cells. Expression of DC-LAMP increases progressively during in vitro DC differentiation, but sharply upon activation with LPS, TNFalpha, or CD40L. Confocal microscopy confirmed the lysosomal distribution of the protein. Furthermore, DC-LAMP was found in the MHC class II compartment immediately before the translocation of MHC class II molecules to the cell surface, after which it concentrates into perinuclear lysosomes. This suggests that DC-LAMP might change the lysosome function after the transfer of peptide-MHC class II molecules to the surface of DC.

Amino Acid Sequence↗
PubMed1999

Transient expression of myosin heavy chain MHCI alpha in rabbit muscle during fast-to-slow transition.

The expression of an alpha-cardiac-like myosin heavy chain, MHCI alpha, was investigated at both the mRNA and protein levels in rabbit tibialis anterior muscle undergoing fast-to-slow transition by continuous chronic low-frequency stimulation (CLFS). According to sequence analyses of the PCR product, the MHCI alpha isoform was found to be identical to the alpha-cardiac MHC expressed in rabbit atrium. In muscles at different degrees of transformation, the upregulation of MHCI alpha mRNA preceded that of the MHCI beta mRNA. At more advanced stages of the transformation, MHCI alpha mRNA decayed while MHCI beta mRNA persisted at high levels. The expression of MHCI alpha, therefore, was transitory. Studies at the protein level were based on immunoblotting using a monoclonal antibody (F88 12F8,1), characterized to be specific to MHCI alpha in rabbit muscle. These studies revealed a similar relationship between initial increase and successive decline of the MHCI alpha protein as seen at the mRNA level. Immunohistochemistry of 30-day stimulated muscle revealed that up to 65% of the fibres expressed the MHCI alpha isoform in combination with other adult MHC isoforms. The most frequent patterns of coexistence were MHCIIa + MHCI alpha + MHCI beta (28%), MHCI alpha + MHCI beta (18%), and MHCIIa + MHCI alpha (11%). According to these combinations, the upregulation of MHCI alpha may be assigned as an intermediate step in the transformation of existing fibres during the MHCIIa-->MHCI beta transition. A small fraction of fibres contained, in addition to the MHCI alpha + MHCI beta and MHCIIa + MHCI alpha combinations, developmental myosin, suggesting that MHCI alpha was also expressed in regenerating fibres originating from satellite cell-derived myotubes.

Animals↗
PubMed1998

Investigation of Agrobacterium-mediated transformation of apple using green fluorescent protein: high transient expression and low stable transformation suggest that factors other than T-DNA transfer are rate-limiting.

To investigate early events of Agrobacterium-mediated transformation of apple cultivars, a synthetic green fluorescent protein gene (SGFP) was used as a highly sensitive, vital reporter gene. Leaf explants from four apple cultivars ('Delicious', 'Golden Delicious', 'Royal Gala' and 'Greensleeves') were infected with Agrobacterium EHA101 harboring plasmid pDM96.0501. Fluorescence microscopy indicated that SGFP expression was first detected 48 h after infection and quantitative analysis revealed a high T-DNA transfer rate. Plant cells with stably incorporated T-DNA exhibited cell division and developed transgenic calli, followed by formation of transgenic shoots at low frequencies. The detection of SGFP expression with an epifluorescence stereomicroscope confirmed the effectiveness of SGFP as a reporter gene for detection of very early transformation events and for screening of putative transformants. The efficiency of the transformation and regeneration process decreased ca. 10,000-fold from Agrobacterium infection to transgenic shoot regeneration, suggesting that factors other than Agrobacterium interaction and T-DNA transfer are rate-limiting steps in Agrobacterium-mediated transformation of apple.

Blotting, Southern↗
PubMed2000

Transient expression of a pea MAP kinase gene induced by gibberellic acid and 6-benzyladenine in unpollinated pea ovaries.

PsMAPK3, a new MAP kinase cDNA, was cloned from ovaries of Pisum sativum L. Expression of PsMAPK3 is at low basal levels in unpollinated ovaries but it is rapidly induced by gibberellic acid (peak at 30 min) and 6-benzyladenine (peak at 45 min). Both treatments promoted the development of a parthenocarpic fruit. In situ hybridization localized PsMAPK3 mRNA in ovules. The transcript was additionally detected in the mesocarp when it is expanding in response to the treatments. These observations suggest that gibberellins and cytokinins regulate PsMAPK3 mRNA levels in pea ovary shortly after fruit set is induced.

Adenine↗
PubMed1997

Smooth muscle myosin light chain kinase is transiently expressed in skeletal muscle during embryogenesis and muscle regeneration both in vivo and in vitro.

By using a polyclonal antibody raised against smooth muscle Myosin Light Chain Kinase of adult chicken we show that the 135 kDa smooth muscle Myosin Light Chain Kinase isoform is present in neonatal and regenerating rat skeletal muscle, as well as in adult atrial myocardium. No reaction was evident in adult skeletal muscle fibres. In neonatal and in early regenerating muscle smooth muscle Myosin Light Chain Kinase is associated with embryonic myosin as revealed by their co-presence in muscle fibres. Experiments in vitro show the same results in myotubes. In atrial myocardium there is a patchy positivity in certain group of myocytes. Immunoblotting experiments show in muscle cell cultures, in neonatal and in regenerating skeletal muscle a protein band with electrophoretic mobility corresponding to that of smooth muscle Myosin Light Chain Kinase. These results suggest that the expression of smooth muscle Myosin Light Chain Kinase is not fully tissue-specific and that regulation of the contractile machinery could be different during myogenesis and in adulthood, in relation to the peculiar dynamic characteristics of developing muscles.

Animals↗
PubMed2004

Transient expression of MDR-1/P-glycoprotein in a model of partial cortical devascularization.

1. MDR-1 gene product confer to expressing cells the multidrug resistance phenotype to a broad range of drugs and xenobiotics. 2. It is known that different stress signals are able to induce MDR-1 expression through different promoters. 3. In a rat model of ischemia by partial cortical devascularization we studied the expression profile and the cellular localization of MDR-1 after 1, 3, 7, 14 and 28 days post lesion (DPL). 4. Using two different antibody clones we found that MDR-1 is expressed in cortical and striatal neurons ipsilateral to the devascularizing lesion, starting at 1DPL, showing a maximum at 7DPL to be thereafter reduced until undetectable levels by 28DPL. 5. MDR-1 expression may be defining a neuronal subset with a particular pharmacological profile.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

Protein kinase C-mediated Ca2+ entry in HEK 293 cells transiently expressing human TRPV4.

1. We investigated whether protein kinase C (PKC) activation stimulates Ca2+ entry in HEK 293 cells transfected with human TRPV4 cDNA and loaded with fura-2. 2. Phorbol 12-myristate 13-acetate (PMA), a PKC-activating phorbol ester, increased the intracellular Ca2+ concentration ([Ca2+]i) in a dose-dependent manner, with an EC50 value of 11.7 nm. Exposure to a hypotonic solution (HTS) after PMA further increased [Ca2+]i. Two other PKC-activating phorbol esters, phorbol 12,13-didecanoate (PDD) and phorbol 12,13-dibutyrate, also caused [Ca2+]i to increase. 3. The inactive isomer 4alpha-PMA was less effective and the peak [Ca2+]i increase was significantly smaller than that induced by PMA. In contrast, 4alpha-PDD produced a monophasic or biphasic [Ca2+]i increase with a different latency, while 4alpha-phorbol had no effect. 4. The PMA-induced [Ca2+]i increase was abolished by prior exposure to bisindolylmaleimide (BIM), a PKC-specific inhibitor, and suppressed by the nonspecific PKC inhibitor 1-(5-isoquinolinesulphonyl)-2-methylpiperazine. The [Ca2+]i increase induced by 4alpha-PMA, 4alpha-PDD or HTS was not significantly affected by BIM. 5. These results suggest that both PKC-dependent and -independent mechanisms are involved in the phorbol ester-induced activation of TRPV4, and the PKC-independent pathway is predominant in HTS-induced Ca2+ entry.

Calcium↗