Expression of microinjected hsp 70/CAT and hsp 30/CAT chimeric genes in developing Xenopus laevis embryos

Development ◽  
1989 ◽  
Vol 106 (2) ◽  
pp. 271-281
Author(s):  
P.H. Krone ◽  
J.J. Heikkila
Keyword(s):  
Xenopus Laevis ◽  
Fusion Gene ◽  
Developmental Regulation ◽  
Hsp 70 ◽  
Inhibitory System ◽  
Developmentally Regulated ◽  
Promoter Sequences ◽  
Chimeric Genes ◽  
Stage Of Development ◽  
Tailbud Stage

The expression of microinjected chimeric genes containing Drosophila hsp 70 and Xenopus hsp 70 and hsp 30 promoters linked to the reporter gene coding for bacterial chloramphenicol acetyltransferase (CAT) was examined during early development of Xenopus laevis. Heat-inducible expression of fusion genes containing either the Drosophila hsp 70 promoter (1100 bp) or the Xenopus hsp 70 promoter (750 bp) was first detectable after the midblastula stage of development. This coincides with the embryonic stage at which the endogenous hsp 70 gene is first heat-inducible. A Xenopus hsp 30/CAT fusion gene containing 350 bp of promoter sequences was also heat-inducible after the midblastula stage unlike the endogenous hsp 30 genes which were not heat-inducible until the early tailbud stage (stage 23–24). Sequences that are present within either the coding or 3′ region of the hsp 30 clone do not cause the microinjected hsp 30 gene to be developmentally regulated in a normal manner. Additionally, microinjected hsp 30 gene sequences have no effect on the developmental regulation of endogenous hsp 30 genes which continue to be activated at the tailbud stage of development. Our data suggest, that an inhibitory system, which may control the expression of the endogenous hsp 30 gene during development, does not regulate the expression of the injected hsp 30 gene.

An investigation into early placental ontogeny: allantoic attachment to the chorion is selective and developmentally regulated

Development ◽  
1995 ◽  
Vol 121 (2) ◽  
pp. 407-416 ◽  
Author(s):  
K.M. Downs ◽  
R.L. Gardner
Keyword(s):  
Developmental Regulation ◽  
Initial Attachment ◽  
Developmentally Regulated ◽  
Somite Stage ◽  
Differential Adhesion ◽  
Stage Of Development ◽  
Initial Stage ◽  
Directed Growth ◽  
Do So

Culture of postimplantation conceptuses was used in conjunction with microsurgery to investigate the timing, the mechanism and the developmental regulation of chorioallantoic fusion in the mouse. The timing of fusion was determined in both freshly recovered conceptuses and in those that had been cultured from as early as the mid-streak stage. Attachment of the allantois to the chorion was found to have occurred in most conceptuses by the 6-somite stage, irrespective of whether they had been cultured. In investigating the mechanism of fusion, we wished to determine whether it depended on directed growth of the allantoic bud or on its differential adhesion to the chorion. Microsurgery was used to transplant allantoic tissue into the exocoelomic cavity of conceptuses from which the resident allantois had been removed. In synchronous grafting experiments, transplanted allantoises typically attached to the chorion despite loss of their connection with the hindgut region of the fetus. Hence selective attachment of the allantois to the chorion clearly cannot depend simply on its directed growth. While the transplanted allantoic tissue attached to the chorion selectively, it did not attach to it precociously, despite being favourably positioned to do so. These findings argue that the initial attachment of the allantois to the chorion depends on a selective adhesive mechanism that is developmentally regulated. Further grafting experiments in which donor conceptuses were either more or less advanced than hosts revealed that attachment of the allantois to the chorion depends primarily on the stage of the allantois rather than on the stage of the chorion. Collectively, these findings support the hypothesis that the initial stage of chorioallantoic fusion depends on selective adhesion between regionally differentiated mesodermal surfaces which is governed principally by the stage of development of the allantois.

Analysis of hsp 30, hsp 70 and ubiquitin gene expression in Xenopus laevis tadpoles

Development ◽  
1988 ◽  
Vol 103 (1) ◽  
pp. 59-67
Author(s):  
P.H. Krone ◽  
J.J. Heikkila
Keyword(s):  
Heat Shock ◽  
Xenopus Laevis ◽  
Temporal Pattern ◽  
Size Range ◽  
Continuous Exposure ◽  
Hsp 70 ◽  
Blastula Stage ◽  
Tailbud Stage ◽  
Actin Mrna ◽  
Continuous Heat

Heat-induced accumulation of hsp 30 mRNA (1.1 kb) during early development of Xenopus laevis was first detectable at the tailbud stage (stage 30–34). This contrasts with heat-induced accumulation of hsp 70 mRNA (2.7 kb) and ubiquitin mRNA (size range = 1.7–3.1 kb), which was first detectable at the mid- to late-blastula stage. Continuous exposure of tadpoles to a 33 degrees C heat shock resulted in a coordinate, transient accumulation of hsp 30, hsp 70 and ubiquitin mRNA. A coordinate, temporal pattern was also observed for the decay of hsp 30, hsp 70 and ubiquitin mRNA in tadpoles recovering at 22 degrees C following a 1 h heat shock at 33 degrees C. Thus, while hsp 30 genes are regulated differently during development compared with hsp 70 and ubiquitin genes, these genes all exhibit a coordinate heat-inducible pattern of expression at the tadpole stage. Levels of alpha-cardiac actin mRNA remained unchanged during continuous heat shock and recovery experiments.

scholarly journals Identification and developmental regulation of a neuron-specific subunit of cytoplasmic dynein.

1996 ◽  
Vol 7 (2) ◽  
pp. 331-343 ◽  
Author(s):  
K K Pfister ◽  
M W Salata ◽  
J F Dillman ◽  
E Torre ◽  
R J Lye
Keyword(s):  
Axonal Transport ◽  
Developmental Regulation ◽  
Cytoplasmic Dynein ◽  
Retrograde Axonal Transport ◽  
Protein Isoforms ◽  
Cultured Neurons ◽  
Developmentally Regulated ◽  
Time Period ◽  
Intermediate Chains

Cytoplasmic dynein is the microtubule minus-end-directed motor for the retrograde axonal transport of membranous organelles. Because of its similarity to the intermediate chains of flagellar dynein, the 74-kDa intermediate chain (IC74) subunit of dynein is thought to be involved in binding dynein to its membranous organelle cargo. Previously, we identified six isoforms of the IC74 cytoplasmic dynein subunit in the brain. We further demonstrated that cultured glia and neurons expressed different dynein IC74 isoforms and phospho-isoforms. Two isoforms were observed when dynein from glia was analyzed. When dynein from cultured neurons was analyzed, six IC74 isoforms were observed, although the relative amounts of the dynein isoforms from cultured neurons differed from those found in dynein from brain. To better understand the role of the neuronal IC74 isoforms and identify neuron-specific IC74 dynein subunits, the expression of the IC74 protein isoforms and mRNAs of various tissues were compared. As a result of this comparison, the identity of each of the isoform spots observed on two-dimensional gels was correlated with the products of each of the IC74 mRNAs. We also found that between the fifteenth day of gestation (E15) and the fifth day after birth (P5), the relative expression of the IC74 protein isoforms changes, demonstrating that the expression of IC74 isoforms is developmentally regulated in brain. During this time period, there is relatively little change in the abundance of the various IC74 mRNAs. The E15 to P5 time period is one of rapid process extension and initial pattern formation in the rat brain. This result indicates that the changes in neuronal IC74 isoforms coincide with neuronal differentiation, in particular the extension of processes. This suggests a role for the neuronal IC74 isoforms in the establishment or regulation of retrograde axonal transport.

Tissue-specific and developmental regulation of rod opsin chimeric genes in transgenic mice

Neuron ◽  
1991 ◽  
Vol 6 (2) ◽  
pp. 201-210 ◽  
Author(s):  
Janis Lem ◽  
Meredithe L. Applebury ◽  
Jeffrey D. Falk ◽  
John G. Flannery ◽  
Melvin I. Simon
Keyword(s):  
Transgenic Mice ◽  
Developmental Regulation ◽  
Tissue Specific ◽  
Chimeric Genes

scholarly journals Rat lung lectin synthesis, degradation and activation. Developmental regulation and modulation by dexamethasone

1987 ◽  
Vol 245 (3) ◽  
pp. 683-690 ◽  
Author(s):  
L B Clerch ◽  
P L Whitney ◽  
D Massaro
Keyword(s):  
Binding Protein ◽  
Developmental Regulation ◽  
Fold Increase ◽  
Rat Lung ◽  
Absolute Rate ◽  
Lectin Activity ◽  
Developmentally Regulated ◽  
Rat Pups ◽  
The Absolute

Soluble lectins are widely distributed cell-agglutinating proteins. Their activity is developmentally regulated in several tissues, including the lung, but virtually nothing is known about the mechanisms of the developmental regulation or the turnover of these proteins. We studied mechanisms that might be responsible for the developmentally regulated changes in the activity of a lectin (beta-galactoside-binding protein) found in the lung, and determined if its activity or turnover could be modulated by treatment of rat pups with a glucocorticosteroid hormone (dexamethasone). Our studies on the activity and turnover of the lectin indicated that the peak of lectin activity (units/mg of protein) that occurred at age 12 days appeared to be brought about by two means: an increase in the activity of the lectin molecule itself (units/micrograms of lectin) that occurred at age 8 days, and 1.5-fold increase in the absolute rate of lectin synthesis at age 11 days. The decline in lectin activity was associated with a decrease in its rate of synthesis, return to the baseline extent of activation, and an increased rate of degradation. Treatment of rat pups with dexamethasone diminished the peak of lectin activity (units/mg of protein) by about 25%. This effect of dexamethasone was due, at least in part, to the complete prevention of activation of the lectin molecule (units/micrograms of lectin) and a premature increase in the rate of lectin degradation. Perhaps the normal fall in lectin activity after age 11 days is caused by mechanisms induced by the increase in serum corticosteroid that occurs at that age.

scholarly journals Developmental regulation of specific protein interactions with an enhancerlike binding site far upstream from the avian very-low-density apolipoprotein II gene.

1990 ◽  
Vol 10 (1) ◽  
pp. 154-164 ◽  
Author(s):  
P A Hoodless ◽  
R N Roy ◽  
A K Ryan ◽  
R J Haché ◽  
M Z Vasa ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Developmental Regulation ◽  
Consensus Sequence ◽  
Specific Protein ◽  
Low Density ◽  
Nuclear Factor ◽  
Stage Of Development ◽  
Nuclear Extracts ◽  
Enhancer Binding Protein ◽  
Nuclear Factor 1

Expression of the avian very-low-density apolipoprotein II (apoVLDLII) gene is completely dependent on estrogen and restricted to the liver. We have identified binding sites for nonhistone nuclear proteins located between -1.96 and -2.61 kilobases. One of these sites, located at -2.6 kilobases (designated site 1), was found to span an MspI site that becomes demethylated between days 7 and 9 of embryogenesis, the stage of development at which competence to express the apoVLDLII gene begins to be acquired. Levels of the factor(s) involved were high at day 7 of embryogenesis, decreased two- to threefold by days 9 to 11, and continued to decline more slowly until hatching. Furthermore, the mobility of the complex formed underwent a well-defined shift between days 11 to 13 embryogenesis. Methylation interference studies showed that modification of the outer guanosines of the MspI site resulted in marked inhibition of the formation of the protein-DNA complex. Competition studies, fractionation of nuclear extracts, and tissue distribution indicated that the factor was not the avian homolog of hepatocyte nuclear factor 1, nuclear factor 1, or CCAAT/enhancer-binding protein (C/EBP). However, site 1 could complete for binding to an oligonucleotide, previously shown to be recognized by C/EBP, in a nonreciprocal fashion. These studies demonstrate that the sequence recognized by the protein includes a C/EBP consensus sequence but that elements in addition to the core enhancer motif are essential for binding.

Developmental regulation of a novel repetitive protein of Trypanosoma brucei

1987 ◽  
Vol 7 (8) ◽  
pp. 2838-2844
Author(s):  
M R Mowatt ◽  
C E Clayton
Keyword(s):  
Trypanosoma Brucei ◽  
Tandem Repeats ◽  
Signal Sequence ◽  
Developmental Regulation ◽  
Developmentally Regulated ◽  
Hydrophobic Domain ◽  
Reading Frame ◽  
Amino Terminal ◽  
Membrane Bound

Trypanosoma brucei undergoes many morphological and biochemical changes during transformation from the bloodstream trypomastigote to the insect procyclic trypomastigote form. We cloned and determined the complete nucleotide sequence of a developmentally regulated cDNA. The corresponding mRNA was abundant in in vitro-cultivated procyclics but absent in bloodstream forms. The trypanosome genome contains eight genes homologous to this cDNA, arranged as four unlinked pairs of tandem repeats. The longest open reading frame of the cDNA predicts a protein of 15 kilodaltons, the central portion of which consists of 29 tandem glutamate-proline dipeptides. The repetitive region is preceded by an amino-terminal signal sequence and followed by a hydrophobic domain that could serve as a membrane anchor; the mRNA was found on membrane-bound polyribosomes. These results suggest that the protein is membrane associated.

Pulmonary vascular response to normoxia and KCa channel activity is developmentally regulated

2001 ◽  
Vol 280 (6) ◽  
pp. L1250-L1257 ◽  
Author(s):  
Michael T. Rhodes ◽  
Valerie A. Porter ◽  
Connie B. Saqueton ◽  
Jean M. Herron ◽  
Ernesto R. Resnik ◽  
...  
Keyword(s):  
Developmental Regulation ◽  
Pulmonary Arteries ◽  
Critical Time ◽  
Pulmonary Vasculature ◽  
Mrna Levels ◽  
Channel Activity ◽  
Developmentally Regulated ◽  
Channel Expression ◽  
Acute Increase ◽  
Pulmonary Artery Smooth Muscle

To address developmental regulation of pulmonary vascular O2 sensing, we tested the hypotheses that 1) fetal but not adult pulmonary artery smooth muscle cells (PASMCs) can directly sense an acute increase in O2, 2) Ca2+-sensitive K+(KCa) channel activity decreases with maturation, and 3) PASMC KCa channel expression decreases with maturation. We used fluorescence microscopy to confirm that fetal but not adult PASMCs are able to sense an acute increase in O2tension. Acute normoxia induced a 22 ± 2% decrease in cytosolic Ca2+ concentration ([Ca2+]i) in fetal PASMCs and no change in [Ca2+]i in adult PASMCs ( P < 0.01). The effects of K+channel antagonists were studied on fetal and adult PASMC [Ca2+]i. Iberiotoxin (10−9 M) caused PASMC [Ca2+]i to increase by 694 ± 22% in the fetus and caused no change in adult PASMCs. KCa channel expression and mRNA levels in distal pulmonary arteries from fetal and adult sheep were examined. Both KCachannel protein and mRNA expression in the distal pulmonary vasculature decreased with maturation. We conclude that maturation-dependent changes in PASMC O2 sensing render the fetal PASMCs uniquely sensitive to an acute increase in O2 tension at a biologically critical time point.

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