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Biomedical subjects

Z Wei

Publications and source records attributed to Z Wei.

At least 37 records · Page 2Linked to original sources
PubMed2001

Balanced ultrafiltration, modified ultrafiltration, and balanced ultrafiltration with modified ultrafiltration in pediatric cardiopulmonary bypass.

This study evaluates the effect of balanced ultrafiltration, modified ultrafiltration, and balanced ultrafiltration with modified ultrafiltration on inflammatory mediators in children's open-heart surgery. Eighty children with congenital heart disease were randomly divided into four groups: control group (C group); balanced ultrafiltration group (BUF group); modified ultrafiltration group (MUF group); and balanced ultrafiltration with modified ultrafiltration group (B+M group). Clinical data of these groups were similar. Tumor necrosis factor (TNF), interleukin-8(IL-8), and E-selectin were measured at the beginning of cardiopulmonary bypass (CPB), 30 min later, at the cessation of CPB, at the cessation of MUF (MUF group and B+M group), and 2 hours postoperatively. During CPB, the concentrations of TNF, IL-8, and E-selectin increased significantly in C and MUF groups and did not change significantly in BUF and B+M groups. In the period of MUF, TNF and IL-8 increased; whereas, E-selectin did not change. The study shows that ultrafiltration can filter out the inflammatory mediators, but only BUF can decrease the concentrations of them. Moreover, MUF only can concentrate blood. Combining both techniques has both effects, but the effect of BUF was offset by MUF.

Cardiopulmonary Bypass↗
PubMed2000

Sulfakinins reduce food intake in the desert locust, Schistocerca gregaria.

In vertebrates, the peptides cholecystokinin (CCK), neuropeptide Y, galanin, and bombesin are known to be involved in the control of food intake. We report here that insect sulfakinins, peptides which display substantial sequence similarities with the vertebrate gastrin/CCK peptide family, significantly inhibit food uptake in fifth instar nymphs of the locust, Schistocerca gregaria. Upon injection of Lom-sulfakinin, a neuropeptide present in the corpus cardiacum of locusts, food intake was significantly reduced in a dose-dependent manner within a fixed 20 min time period. The induced effect ranged from 13% inhibition (10 pmol of injected peptide) to over 50% inhibition at 1 nmol. Other naturally occurring sulfakinins from different insect species also elicited this satiety effect. Analogous to the satiety effect of CCK in vertebrates, the sulfate group is required for activity. No effect on the palptip resistance was found after injection with sulfakinin. Therefore it seems unlikly that sulfakinins reduce food intake by decreasing the sensitivity of the taste receptors.

Journal Article↗
PubMed2000

Pycnogenol inhibits tumor necrosis factor-alpha-induced nuclear factor kappa B activation and adhesion molecule expression in human vascular endothelial cells.

The transcriptional regulatory protein nuclear factor kappa B (NF-kappa B) participates in the control of gene expression of many modulators of inflammatory and immune responses, including vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). The heightened expression of these adhesion molecules has been reported to play a critical role in atherosclerosis, inflammation, ischemic vascular disorders, diabetes, and cancer metastasis. In the present study, we investigated the effect of pycnogenol, an antioxidant phytochemical, on the activation of NF-kappa B and the induction of VCAM-1 and ICAM-1 in tumor necrosis factor (TNF)-alpha-treated human umbilical vein endothelial cells (HUVECs). Gel-shift analysis of HUVEC demonstrated that pretreatment with pycnogenol exhibited a concentration-dependent suppression of TNF-alpha-induced activation of NF-kappa B. Induction of VCAM-1 and ICAM-1 surface expression by TNF-alpha was dose-dependently reduced by pycnogenol. TNF-alpha significantly increased the release of superoxide anion and hydrogen peroxide from HUVECs. Pycnogenol dose-dependently inhibited their release. The ability of pycnogenol to inhibit NF-kappa B activation and VCAM-1 and ICAM-1 expression suggests that this phytochemical may play an important role in halting or preventing the atherogenic process.

Antioxidants↗
PubMed2000

Intratumoral injection with [(188)Re]rhenium sulfide suspension for treatment of transplanted human liver carcinoma in nude mice.

Hepatocellular carcinoma (HCC) is one of the most common malignancies in China. Direct intratumoral injection of nonremovable radioactive material has been widely studied because it could deliver high doses of radiation to target sites and minimize radiation leakage to non-target organs or tissues. Thirty nude mice bearing SMMC 7721 human liver carcinoma were used for the biodistribution study after intratumoral injection of [(188)Re]rhenium sulfide suspension or sodium [(188)Re]perrhenate solution. Another 30 tumor-bearing mice were divided into six groups, four groups of which were treated with a 0.1 ml [(188)Re]rhenium sulfide suspension at doses of 3.7, 7.4, 18.5, 29.6 MBq by a single intratumoral injection. For control studies, to study the tumor inhibiting ratio, the remaining two groups were injected with nonradioactive rhenium sulfide suspension and Hanks' balanced salt solution, respectively. The injections were repeated 6 days later. The retention percentages of radioactivity (%ID) in tumors injected with [(188)Re]rhenium sulfide suspension were 90.96+/-6.63%, 86.09+/-22.58% and 87.62+/-13.97% at 1, 24 and 48 h, respectively. Tumor inhibition ratios are as high as 89% when the outer space of tumor (0.5-0.6 cm from center) received about 507.6 Gy doses. Intratumoral injection of [(188)Re]rhenium sulfide suspension results in high tumor retention indicating this approach has strong potential for the treatment of hepatic carcinoma.

Animals↗
PubMed2000

Regulation of hrp genes and type III protein secretion in Erwinia amylovora by HrpX/HrpY, a novel two-component system, and HrpS.

Two novel regulatory components, hrpX and hrpY, of the hrp system of Erwinia amylovora were identified. The hrpXY operon is expressed in rich media, but its transcription is increased threefold by low pH, nutrient, and temperature levels--conditions that mimic the plant apoplast. hrpXY is autoregulated and directs the expression of hrpL; hrpL, in turn, activates transcription of other loci in the hrp gene cluster (Z.-M. Wei and S. V. Beer, J. Bacteriol. 177:6201-6210, 1995). The deduced amino -acid sequences of hrpX and hrpY are similar to bacterial two-component regulators including VsrA/VsrD of Pseudomonas (Ralstonia) solanacearum, DegS/DegU of Bacillus subtilis, and UhpB/UhpA and NarX/NarP, NarL of Escherichia coli. The N-terminal signal-input domain of HrpX contains PAS domain repeats. hrpS, located downstream of hrpXY, encodes a protein with homology to WtsA (HrpS) of Erwinia (Pantoea) stewartii, HrpR and HrpS of Pseudomonas syringae, and other delta54-dependent, enhancer-binding proteins. Transcription of hrpS also is induced under conditions that mimic the plant apoplast. However, hrpS is not autoregulated, and its expression is not affected by hrpXY. When hrpS or hrpL were provided on multicopy plasmids, both hrpX and hrpY mutants recovered the ability to elicit the hypersensitive reaction in tobacco. This confirms that hrpS and hrpL are not epistatic to hrpXY. A model of the regulatory cascades leading to the induction of the E. amylovora type III system is proposed.

Amino Acid Sequence↗
PubMed2000

Presence of a glycan at a potential N-glycosylation site, Asn-281, of bovine lactoferrin.

This work was performed to clarify the differences in glycan moieties between multiple molecular mass forms of bovine lactoferrins (bovine lactoferrins-a and -b). After digestion of both bovine lactoferrins with cyanogen bromide and V8 protease, glycopeptides were successively purified by concavalin A affinity chromatography and HPLC on an octadecylsilyl column. Four glycopeptides glycosylated at Asn-233, -368, -476, and -545 were obtained from both hydrolysates of bovine lactoferrins-a and -b. On the other hand, a glycopeptide glycosylated at Asn-281 was only detected in hydrolysate of bovine lactoferrin-a, indicating that bovine lactoferrin-a possessed five N-glycosylated sites. The glycan linked to Asn-281 of bovine lactoferrin-a was found to consist of fucose, galactose, and N-acetylgalactosamine in addition to mannose and N-acetylglucosamine. HPLC analysis of this glycan on a normal phase column showed that peaks of several glycans were detected. These glycans changed to one major glycan consisting of only mannose and N-acetylglucosamine on exoglycosidase digestion. From these results, this glycan seemed to be of the complex type and possess heterogeneous structure.

Acetylgalactosamine↗
PubMed2000

Separation of lactoferrin-a and -b from bovine colostrum.

Bovine lactoferrin was separated into lactoferrin-a and lactoferrin-b from bovine colostrum. Lactoferrin-a was eluted at 0.38 M NaCl and lactoferrin-b was eluted at 0.43 M NaCl by carboxymethyl cation-exchange chromatography at pH 7.7, 0.05 M phosphate buffer. The molecular weights were estimated at 84,000 for lactoferrin-a and 80,000 for lactoferrin-b. Lactoferrin-a contents were 258.0 mg/L and lactoferrin-b contents were 524.3 mg/L of colostrum for cow 19. From colostrum to normal milk, total lactoferrin was from 17.1 to 129.4 mg/L during the normal lactational period; however, lactoferrin did not separate clearly into lactoferrin-a and lactoferrin-b. The lactoferrin-a measured from six cows was 258.0, 114.0, 112.8, 64.0, 59.7, and 22.4 mg/ L and the lactoferrin-b 524.3, 331.8, 184.7, 170.7, 129.3, and 44.0 mg/L, respectively. The average was 105.2 mg (31.3%) for lactoferrin-a and 230.8 mg (68.7%) for lactoferrin-b.

Animals↗
PubMed2000

[A study on the preservation of rat kidney with HX-III solution].

This study was conducted to compare the effects of HX-III solution and UW solution on rat kidney transplantation. Inbred Sprague-Dawley rats weighing 200-280 g, were used in allotransplantation. The donors and recipients were of the same sex. The rats were randomly divided into control (UW solution) and experimental (HX-III solution) groups, and each group included 48- and 72-hour preservation subgroups. There were ten rats in each subgroup. Kidneys were flushed with UW solution or HX-III solution and stored at 4 degrees C for 48 or 72 hours. Then, kidney allotransplantations were performed. The results showed that the rates of survival were 100% and 90% in UW group for 48- and 72-hour cold storage, but those in HX-III were 100% and 60%, respectively. With 48-hour preservation, the maximum serum creatinine levels in UW group were similar to those in HX-III group (P > 0.05). With 72-hour preservation, the maximum serum creatinine levels in UW group were lower than those in HX-III group (P < 0.05). On the 14th day posttransplantation, the histological findings on Kidneys in the two groups for 48-hour cold storage were almost the same, but the grafted kidneys in HX-III group were damaged more seriously than those in UW group for 72 hour cold storage. On the 28th day posttransplantation, the histological findings on the grafted kidneys were basically normal in all groups. The authors concluded that HX-III solution could preserve rat kidney for 48 hours effectively.

Animals↗
PubMed2000

[Effect of antisense oligonucleotides on the TXA2 production of macrophages stimulated by endotoxin].

OBJECTIVE: To select efficient fragments which can inhibit gene expression of thromboxane synthase and production of thromboxane A2. METHODS: Rat peritoneal macrophages were incubated with oligonucleotides (ODNs) and endotoxin (which was composed of lipopolysaccharide) for 24 hours. The TXB2 content was determined by RIA. Thromboxane synthase (TXS) mRNA expression was measured with RNA dot hybridization. RESULTS: The concentration of TXB2 in ODN I group was (69.7 +/- 10.9) pg/microgram cell protein, lower than those in control group (100.6 +/- 28.6) pg/microgram cell protein (P < 0.05, n = 4), TXS mRNA expression level in ODN I group was decreased as compared to those in control group. Neither in ODN II nor in ODN III group were there any changes on TXB2 contents and TXS mRNA levels. CONCLUSIONS: ODN I can inhibit the production of TXA2 and the gene expression of thromboxane synthase from macrophages stimulated by endotoxin.

Animals↗
PubMed2000

[Association of microtubule promoting and binding activity of tau with its phosphorylation sites].

OBJECTIVE: To explore the association between the abnormal phosphorylation sites found in Alzheimer disease (AD) tau and the inhibition of its biological activity. METHODS: Ultracentrifugation, chromatography, manual Edman degradation and autosequence techniques were used to prepare and phosphorylate human recombinant tau, isolate and purify 32P tau peptides and determine phosphorylation sites. RESULTS: (1) Phosphorylation of tau by casein kinase-1 (CK-1), cyclic AMP-dependent protein kinase (PKA) and glycogen synthetase kinase-3 (GSK-3) differentially inhibited its biological activity, and the inhibition of this activity of tau by GSK-3 was significantly increased if tau was prephosphorylated by CK-1 or PKA. The most potent inhibition was seen by a combined phosphorylation of tau with PKA and GSK-3. (2) The treatment of tau by PKA and GSK-3 combination induced phosphorylation of tau at Ser-195, Ser-198, Ser-199, Ser-202, Thr-205, Thr-231, Ser-235, Ser-262, Ser-356, Ser-404, whereas only Thr-181, Ser-184, Ser-262, Ser-356 and Ser-400 were phosphorylated by GSK-3 alone under the same conditions. Among the above-mentioned phosphorylation sites, Ser-198, Ser-199, Ser-202, Thr-205, Thr-231, Ser-235, Ser-262, Ser-400 and Ser-404 were seen in Alzheimer tau. The phosphorylation of Ser-262 only slightly inhibited its biological activity, and Ser-198, Ser-199, Ser-202, Thr-231, Ser-235, Ser-400 and Ser-404 also presented in fetal tau which was highly active, suggesting that Thr-205 was the unique site which both caused the potent inhibition of biological activity and specifically presented in AD abnormally phosphorylated tau. CONCLUSIONS: Phosphorylation of Thr-205 might play a key role in tau pathology in AD.

Alzheimer Disease↗
PubMed1999

Regulation of the biosynthesis of N-acetylglucosaminylpyrophosphoryldolichol, feedback and product inhibition.

The assembly of the core oligosaccharide region of asparagine-linked glycoproteins proceeds by means of the dolichol pathway. The first step of this pathway, the reaction of dolichol phosphate with UDP-GlcNAc to form N-acetylglucosaminylpyrophosphoryldolichol (GlcNAc-P-P-dolichol), is under investigation as a possible site of metabolic regulation. This report describes feedback inhibition of this reaction by the second intermediate of the pathway, N-acetylglucosaminyl-N-acetylglucosaminylpyrophosphoryldolichol (GlcNAc-GlcNAc-P-P-dolichol), and product inhibition by GlcNAc-P-P-dolichol itself. These influences were revealed when the reactions were carried out in the presence of showdomycin, a nucleoside antibiotic, present at concentrations that block the de novo formation of GlcNAc-GlcNAc-P-P-dolichol but not that of GlcNAc-P-P-dolichol. The apparent K(i) values for GlcNAc-P-P-dolichol and GlcNAc-GlcNAc-P-P-dolichol under basal conditions were 4.4 and 2.8 microM, respectively. Inhibition was also observed under conditions where mannosyl-P-dolichol (Man-P-dol) stimulated the biosynthesis of GlcNAc-P-P-dolichol; the apparent K(i) values for GlcNAc-P-P-dolichol and GlcNAc-GlcNAc-P-P-dolichol were 2.2 and 11 microM, respectively. Kinetic analysis of the types of inhibition indicated competitive inhibition by GlcNAc-P-P-dolichol toward the substrate UDP-GlcNAc and non-competitive inhibition toward dolichol phosphate. Inhibition by GlcNAc-GlcNAc-P-P-dolichol was uncompetitive toward UDP-GlcNAc and competitive toward dolichol phosphate. A model is presented for the kinetic mechanism of the synthesis of GlcNAc-P-P-dolichol. GlcNAc-P-P-dolichol also exerts a stimulatory effect on the biosynthesis of Man-P-dol, i.e. a reciprocal relationship to that previously observed between these two intermediates of the dolichol pathway. This network of inhibitory and stimulatory influences may be aspects of metabolic control of the pathway and thus of glycoprotein biosynthesis in general.

Acetylglucosamine↗
PubMed1999

Simulated ischemia in flow-adapted endothelial cells leads to generation of reactive oxygen species and cell signaling.

We have previously shown that increased reactive oxygen species (ROS) generation occurs with ischemia in the oxygenated lung and have hypothesized that mechanotransduction is the initiating event. In the present study, we developed an in vitro model of oxygenated ischemia by interrupting medium flow to flow-adapted bovine pulmonary artery endothelial cells in an artificial capillary system. Cellular oxygenation during the "ischemic" period was maintained by perfusing medium over the abluminal surface of porous capillaries. Cells were assessed for ROS generation, nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) binding activities, and DNA synthesis using dichlorofluorescein fluorescence by flow cytometry and spectrofluorometry, electrophoretic mobility shift assay of nuclear extracts with NF-kappaB-specific or AP-1-specific (32)P-labeled oligonucleotides, and (3)H-thymidine incorporation into DNA. Cells that were flow adapted for 2 to 7 days with 1 to 2 dyne/cm(2) shear stress exhibited a 1.6- to 1.9-fold increase in ROS generation during 1 hour of simulated ischemia compared with continuously perfused cells. This effect was abolished by diphenyleneiodonium chloride (DPI), indicating a role for a flavoprotein such as NADPH oxidase. The increase in ROS generation with ischemia was similar for cells from low and high passages. With ischemia, flow-adapted cells exhibited increases of 1.7-fold in nuclear NF-kappaB and 1.5-fold in nuclear AP-1; these changes were abolished by pretreatment with N-acetylcysteine or DPI. Ischemia for 24 hours resulted in a 1.8-fold increase of (3)H-thymidine incorporation into DNA and a significant increase of cells entering the cell cycle, as indicated by flow cytometry with propidium iodide. We conclude that flow-adapted endothelial cells generate ROS with ischemia that results in activation of NF-kappaB and AP-1 and an increase of DNA synthesis. This effect is not mediated by hypoxia, implicating a role for mechanotransduction in ischemia-mediated cell signaling.

Animals↗
PubMed1999

Functional analysis of conserved cysteines in heparan sulfate N-deacetylase-N-sulfotransferases.

N-Deacetylase-N-sulfotransferases (NDANST) catalyze the two initial modifications of the polysaccharide precursor in the biosynthesis of heparin and heparan sulfate. These modifications are the gating steps in establishing growth factor protein-binding domains of these glycosaminoglycans. We have undertaken a structure-activity analysis of the 841-amino acid Golgi-luminal portion of the rat liver NDANST to localize the two enzymatic functions. Each activity can be assayed in vitro independently of the other when provided with the appropriate substrate, and N-ethylmaleimide treatment selectively inactivates the deacetylase activity. In this study, dithiothreitol treatment of the rat liver NDANST was shown to inactivate the sulfotransferase function, while stimulating deacetylase activity 2-3-fold over the native protein. Site-directed mutagenesis of the eight cysteine (Cys) residues in the rat liver NDANST that are conserved in the mouse mastocytoma protein produced three important findings regarding the localization of each enzymatic function: 1) derivatization of Cys486 with N-ethylmaleimide resulted in total inactivation of the deacetylase activity based on steric hindrance of the active site (this residue was shown not to be involved in enzymatic catalysis), 2) substitution of either Cys159 or Cys486 with alanine resulted in enhanced activity of the deacetylase to the level obtained by dithiothreitol treatment, and 3) alanine substitution of Cys818 or Cys828 completely inactivated the sulfotransferase activity, while substitution of Cys586 or Cys601 resulted in a 90% loss in activity. These findings suggest that the two enzymatic domains within the NDANST localize to different portions of the protein, with two disulfide pairs toward the COOH-terminal half of the protein necessary for the sulfotransferase activity, and Cys residues within the NH2-terminal half influencing or located near the active site of the deacetylase functionality.

Alanine↗
PubMed1999

Ginkgo biloba inhibits hydrogen peroxide-induced activation of nuclear factor kappa B in vascular endothelial cells.

The present study determined the effects of Ginkgo biloba extract (GBE) on the activation of nuclear factor kappa B (NF-kappaB) and the level of hydrogen peroxide (H2O2) in bovine pulmonary artery endothelial cells (PAEC). H2O2 showed a concentration-dependent activation of NF-kappaB. GBE demonstrated a concentration-dependent suppression of NF-kappaB activated by H2O2. GBE directly scavenged H2O2 in a cell-free system; it also decreased H2O2 levels in PAEC. These results suggest that the inhibitory effect of GBE on H2O2-induced NF-kappaB activation may be caused by its scavenging and suppression of H2O2. Our experiments demonstrate that GBE can inhibit NF-kappaB activation induced by H2O2 and may thus be effective for the prevention or treatment of atherosclerosis and other disorders related to NF-kappaB activation.

Animals↗
PubMed1999

Vitamin E regulates mitochondrial hydrogen peroxide generation.

The mitochondrial electron transport system consumes more than 85% of all oxygen used by the cells, and up to 5% of the oxygen consumed by mitochondria is converted to superoxide, hydrogen peroxide, and other reactive oxygen species (ROS) under normal physiologic conditions. Disruption of mitochondrial ultrastructure is one of the earliest pathologic events during vitamin E depletion. The present studies were undertaken to test whether a direct link exists between vitamin E and the production of hydrogen peroxide in the mitochondria. In the first experiment, mice were fed a vitamin E-deficient or-sufficient diet for 15 weeks, after which the mitochondria from liver and skeletal muscle were isolated to determine the rates of hydrogen peroxide production. Deprivation of vitamin E resulted in an approximately 5-fold increase of mitochondrial hydrogen peroxide production in skeletal muscle and a 1-fold increase in liver when compared with the vitamin E-supplemented group. To determine whether vitamin E can dose-dependently influence the production of hydrogen peroxide, four groups of male and female rats were fed diets containing 0, 20, 200, or 2000 lU/kg vitamin E for 90 d. Results showed that dietary vitamin E dose-dependently attenuated hydrogen peroxide production in mitochondria isolated from liver and skeletal muscle of male and female rats. Female rats, however, were more profoundly affected by dietary vitamin E than male rats in the suppression of mitochondrial hydrogen peroxide production in both organs studied. These results showed that vitamin E can directly regulate hydrogen peroxide production in mitochondria and suggest that the overproduction of mitochondrial ROS is the first event leading to the tissue damage observed in vitamin E-deficiency syndromes. Data further suggested that by regulating mitochondrial production of ROS, vitamin E modulates the expression and activation of signal transduction pathways and other redox-sensitive biologic modifiers, and thereby delays or prevents degenerative tissue changes.

Animals↗
PubMed1999

Identification of a new sea urchin ets protein, SpEts4, by yeast one-hybrid screening with the hatching enzyme promoter.

We report the use of a yeast one-hybrid system to isolate a transcriptional regulator of the sea urchin embryo hatching enzyme gene, SpHE. This gene is asymmetrically expressed along the animal-vegetal axis of sea urchin embryos under the cell-autonomous control of maternal regulatory activities and therefore provides an excellent entry point for understanding the mechanism that establishes animal-vegetal developmental polarity. To search for transcriptional regulators, we used a fragment of the SpHE promoter containing several individual elements instead of the conventional bait that contains a multimerized cis element. This screen yielded a number of positive clones that encode a new member of the Ets family, named SpEts4. This protein contains transcriptional activation activity, since expression of reporter genes in yeast does not depend on the presence of the yeast GAL4 activation domain. Sequences in the N-terminal region of SpEts4 mediate the activation activity, as shown by deletion or domain-swapping experiments. The newly identified DNA binding protein binds with a high degree of specificity to a SpHE promoter Ets element and forms a complex with a mobility identical to that obtained with 9-h sea urchin embryo nuclear extracts. SpEts4 positively regulates SpHE transcription, since mutation of the SpEts4 site in SpHE promoter transgenes reduces promoter activity in vivo while SpEts4 mRNA coinjection increases its output. As expected for a positive SpHE transcriptional regulator, the timing of SpEts4 gene expression precedes the transient expression of SpHE in the very early sea urchin blastula.

Amino Acid Sequence↗
PubMed1999

Spatially regulated SpEts4 transcription factor activity along the sea urchin embryo animal-vegetal axis.

Because the transcription of the SpHE gene is regulated cell-autonomously and asymmetrically along the maternally determined animal-vegetal axis of the very early sea urchin embryo, its regulators provide an excellent entry point for investigating the mechanism(s) that establishes this initial polarity. Previous studies support a model in which spatial regulation of SpHE transcription relies on multiple nonvegetal positive transcription factor activities (Wei, Z., Angerer, L. M. and Angerer, R. C. (1997) Dev. Biol. 187, 71-78) and a yeast one-hybrid screen has identified one, SpEts4, which binds with high specificity to a cis element in the SpHE regulatory region and confers positive activation of SpHE promoter transgenes (Wei, Z., Angerer, R. C. and Angerer, L. M. (1999) Mol. Cell. Biol. 19, 1271-1278). Here we demonstrate that SpEts4 can bind to the regulatory region of the endogenous SpHE gene because a dominant repressor, created by fusing SpEts4 DNA binding and Drosophila engrailed repression domains, suppresses its transcription. The pattern of expression of the SpEts4 gene is consistent with a role in regulating SpHE transcription in the nonvegetal region of the embryo during late cleavage/early blastula stages. Although maternal transcripts are uniformly distributed in the egg and early cleaving embryo, they rapidly turn over and are replaced by zygotic transcripts that accumulate in a pattern congruent with SpHE transcription. In addition, in vivo functional tests show that the SpEts4 cis element confers nonvegetal transcription of a beta-galactosidase reporter gene containing the SpHE basal promoter, and provide strong evidence that the activity of this transcription factor is an integral component of the nonvegetal transcriptional regulatory apparatus, which is proximal to, or part of, the mechanism that establishes the animal-vegetal axis of the sea urchin embryo.

Animals↗