Biomedical subjects

T Saeki

Publications and source records attributed to T Saeki.

At least 145 records · Page 8Linked to original sources

PubMed1992

Differential immunohistochemical detection of amphiregulin and cripto in human normal colon and colorectal tumors.

Thirty-six primary human colorectal tumors, 43 noninvolved colon samples that were adjacent to either carcinomas of adenomas, 22 adenomas, and nine normal colon specimens were immunohistochemically examined for the presence and localization of two epidermal growth factor-related peptides, amphiregulin (AR) and cripto. Within the primary tumors, 18 (50%) showed moderate levels of AR expression. Approximately 60% of the tubular and tubulovillous adenomas were positive for AR expression, whereas only 15% of the adjacent, noninvolved colon mucosa expressed AR. A greater proportion of well-differentiated tumors (71%) were positive for AR expression than were poorly differentiated tumors (18%). All of the nine normal colon specimens were positive. Consequently, AR expression appeared to be associated with both normal and malignant epithelial cells that were more differentiated. The distribution of cripto expression was different. Seventy-nine % of the colon tumors expressed cripto with a frequency of expression that was approximately equivalent between well-differentiated and poorly differentiated tumors. Approximately 86% of the tubulovillous adenomas, but only 43% of the tubular adenomas, were positive for cripto expression. In contrast, whereas AR was expressed in normal colon specimens, none of these tissues expressed cripto, and only 12% of the noninvolved normal colon samples adjacent to tumors or adenomas were positive for cripto. Cripto expression therefore appeared related to neoplasia. These data suggest that AR and cripto may be functioning as potential autocrine and/or paracrine growth factors in the colon and that the differential expression of cripto may serve as a potential tumor marker for colonic carcinogenesis.

Adenoma↗

PubMed1992

Specific drug binding by purified lipid-reconstituted P-glycoprotein: dependence on the lipid composition.

We fused P-glycoprotein with beta-galactosidase at the C-terminus aiming to study the mechanism of drug binding of P-glycoprotein in reconstitution experiments. Expression of the fusion protein in NIH 3T3 cells conferred a multidrug-resistant phenotype, suggesting that beta-galactosidase fusion at the C-terminus does not affect the functions of P-glycoprotein. The fusion protein was partially purified by simple immunoprecipitation with anti-beta-galactosidase polyclonal antibody, and its [3H]azidopine binding property was investigated in the presence of various compositions of liposomes. The purified P-glycoprotein, after reconstitution into liposomes, was capable of binding [3H]azidopine. When the cholesterol content of liposomes was increased to a weight ratio of 20%, the specific binding activity of the partially purified fusion protein was stimulated, and when the cholesterol content was increased higher, the binding activity decreased. The binding was specifically decreased by competition with vinblastine. Stigmasterol was less effective, and ergosterol was the least effective in stimulating the specific binding.

3T3 Cells↗

PubMed1992

Different distribution of endothelin receptor subtypes in pulmonary tissues revealed by the novel selective ligands BQ-123 and [Ala1,3,11,15]ET-1.

We have demonstrated the different distribution of two distinct endothelin (ET) receptor subtypes in porcine pulmonary tissues using a radioligand binding assay. The clear differentiation of the subtypes was made possible by the discovery of two compounds, BQ-123 and [Ala1,3,11,15]ET-1 (4AlaET-1), that are highly selective for ETA and ETB receptors, respectively. In the bronchus and lung parenchyma, BQ-123 inhibited 65% and 30% of [125I]ET-1 binding on the sensitive sites, while 4AlaET-1 displaced 25% and 60%, respectively. The combination of the two compounds completely inhibited ET-1 binding in both tissues. An autoradiographic study of [125I]ET-1 binding using BQ-123 and 4AlaET-1 also supported the different localization of two ET receptor subtypes in pulmonary tissues. In particular, the blood vessels and bronchi are rich in ETA, but the lung parenchyma is rich in ETB.

Amino Acid Sequence↗

PubMed1992

Biological profiles of highly potent novel endothelin antagonists selective for the ETA receptor.

We describe novel potent endothelin (ET) antagonists that are highly potent and selective for the ETA receptor (selective to ET-1). Of the synthetic analogs based on ETA antagonist BE-18257A isolated from Streptomyces misakiensis (IC50 value for ETA receptor on porcine aortic smooth muscle cells (VSMCs); 1.4 microM), the compounds BQ-123 and BQ-153 greatly improved the binding affinity of [125I]ET-1 for ETA receptors on VSMCs (IC50; 7.3 and 8.6 nM, respectively), whereas they barely inhibited [125I]ET-1 binding to ETB receptors (nonselective with respect to isopeptides of ET family) in the cerebellar membranes (IC50; 18 and 54 microM, respectively). Associated with the increased affinity for ETA receptors, these peptides antagonized ET-1-induced constriction of isolated porcine coronary artery. However, there was a small amount of ET-1-induced vasoconstriction resistant to these antagonists, which paralleled the incomplete inhibition of [125I]ET-1 binding in the membrane of the aortic smooth muscle layer. These data suggest that the artery has both ETA and ETB receptors responsible for ET-1-induced vasoconstriction. The antagonists shifted the concentration-response curve to the right for ET-1 in the coronary artery, and increased the apparent dissociation constant in the Scatchard analysis of [125I]ET-1 binding on the VSMCs without affecting the binding capacity, indicative of the competitive antagonism for ETA receptor. In conscious rats, pretreatment with the antagonists markedly antagonized ET-1-induced sustained pressor responses in dose-dependent fashion without affecting ET-1-induced transient depressor action, suggesting that the pressor action is mediated by ETA receptors, while the depressor action is mediated by ETB receptors. In addition, pretreatment with the potent antagonists prevented ET-1-induced sudden death in mice. Thus, these potent ETA antagonists should provide a powerful tool for exploring the therapeutic uses of ETA antagonists in putative ET-1-related disorders.

Amino Acid Sequence↗

PubMed1992

A novel radioligand [125I]BQ-3020 selective for endothelin (ETB) receptors.

A linear endothelin (ET) analog, N-acetyl-LeuMetAspLysGluAlaValTyrPheAlaHisLeu-AspIleIleTrp (BQ-3020), is highly selective for ETB receptors. BQ-3020 displaces [125I]ET-1 binding to ETB receptors (nonselective to ET isopeptides) in porcine cerebellar membranes (IC50: 0.2nM) at a concentration 4,700 times lower than that to ETA receptors (selective to ET-1) on aortic vascular smooth muscle cells (VSMC) (IC50: 940nM). BQ-3020 as well as ET-1 and ET-3 elicits vasoconstriction in the rabbit pulmonary artery. The ETA antagonist BQ-123 failed to inhibit this BQ-3020-induced vasoconstriction. Furthermore, BQ-3020 elicits endothelium-dependent vasodilation. These data indicate that BQ-3020 has ETB agonistic activity. The radioligand [125I]BQ-3020 binds to cerebellar membranes at single high affinity sites (Kd = 34.4pM), whereas it scarcely binds to VSMC. [125I]BQ-3020 binding to the cerebellum was displaced by BQ-3020, ET-1 and ET-3 in a nonselective manner (IC50: 0.07-0.17nM). However, the binding of [125I]BQ-3020 was insensitive to the ETA antagonist BQ-123 and other bioactive peptides. Both [125I]ET-1 and [125I]BQ-3020 show slow onset and offset binding kinetics to ETB receptors. These data indicate that the radioligand [125I]BQ-3020 selectively labels ETB receptors and that the slow binding kinetics of ET-1 are dependent on the peptide sequence from Leu6 to Trp21, but not on the structure formed by its two disulfide bridges.

Amino Acid Sequence↗

PubMed1992

Autocrine action of amphiregulin in a colon carcinoma cell line and immunocytochemical localization of amphiregulin in human colon.

Amphiregulin (AR) is a newly discovered glycosylated, 84-amino acid residue polypeptide growth regulator which has sequence homology to the EGF family of proteins. To obtain immunological reagents to study the biological role of AR, two synthetic peptides containing sequences corresponding to distinct regions of AR were used to generate polyclonal antibodies in rabbits. One preparation of antipeptide antibodies directed against residues 26-44 of AR (AR-Ab2) was most effective in the detection of native AR, whereas another preparation of antibodies against residues 8-26 (AR-Ab1) was found to be most efficacious in the detection of AR in formalin-fixed and paraffin-embedded tissues. The growth of a colon carcinoma cell line, Geo, which proliferates autonomously under serum-free conditions, was stimulated by the exogenous addition of AR or EGF. Half-maximal stimulation of this growth was observed at 40 and 200 pM of EGF and AR, respectively. A mAb to the extracellular domain of the EGF receptor blocked the stimulation of cell proliferation induced by the exogenous addition of AR, suggesting that this stimulation was mediated via the EGF receptor. Geo cells were found to constitutively express significant levels of the AR mRNA transcript as determined by analysis of the polymerase chain reaction-amplified cDNA product and AR protein was detected immunocytochemically using the AR-Ab1 antibodies in these cells. AR was immunoprecipitated specifically using the AR-Ab2 antibodies from the conditioned medium of Geo cells, which had been metabolically labeled with [35S]cysteine. The secreted AR migrated as a broad band (18.5-22.5 kD) with a median molecular weight of approximately 20.7 kD in SDS-PAGE. Immunospecific removal of AR from serum-free medium conditioned by the Geo cells and readdition of the AR-depleted medium to Geo cells resulted in an approximately 40% inhibition of cell growth relative to controls. Furthermore, the growth of the Geo cells was also inhibited by approximately 50% by the addition of the anti-EGF receptor mAb alone. These results indicate that AR and the EGF receptor are involved in the autocrine growth of these cells and suggests that AR may act through the EGF receptor via an extracellular autocrine loop. To study the expression of AR in human colon in vivo, AR was localized immunocytochemically in formalin-fixed, paraffin-embedded sections from normal and malignant human colon using the AR-Ab1 antibodies.(ABSTRACT TRUNCATED AT 400 WORDS)

Amphiregulin↗

PubMed1992

In vitro biological profile of a highly potent novel endothelin (ET) antagonist BQ-123 selective for the ETA receptor.

The novel endothelin (ET) receptor antagonists BE-18257A and BE-18257B were isolated from the fermentation products of Streptomyces misakiensis. The above-mentioned compounds inhibited [125I]ET-1 binding to ETA receptors (selective for ET-1) on porcine aortic vascular smooth muscle cells (VSMCs) with IC50 values of 1.4 and 0.47 microM, respectively. [125I]ET-1 binding to ETB receptors (nonselective to ET isopeptides) in cerebellar membranes was not inhibited by either of these compounds even at 100 microM. The synthesized analogue BQ-123 induced extremely potent inhibition of [125I]ET-1 binding to ETA receptors (IC50 of 7.3 nM), but it barely inhibited [125I]ET-1 binding to ETB receptors (IC50 of 18 microM) and binding of various other peptides to their receptors. BQ-123 shifted the concentration-response curve for ET-1 toward the right in porcine isolated coronary arteries, indicative of competitive antagonism for the ETA receptor. However, there was a small amount of BQ-123-insensitive vasoconstriction that paralleled the incomplete inhibition of [125I]ET-1 binding in the membrane of the vascular smooth muscle layer. These data suggest that the artery contracts via both ETA and ETB receptors and that BQ-123 selectively inhibits ETA-mediated contraction. Furthermore, BQ-123 revealed large tissue and species differences in the distribution of ETA receptors. Thus, the potent ETA antagonist BQ-123 should be useful in clarifying the (patho)physiological roles of ETA receptors.

Amino Acid Sequence↗

PubMed1992

[A case of rheumatoid arthritis complicated with pseudotumor around odontoid process successfully treated by methotrexate].

A 69-year-old-female with a history of rheumatoid arthritis since 1975 had suffered from dysesthesia of extremities since October 1989. Radiating pain and weakness occurred when she tried to stand up on Dec. 25 in 1989. She was admitted to our hospital in October 1990. Physical examination showed emaciation, hypesthesia of extremities, hypesthesia over the right chest and back, impaired vibration and position sense, and hyperreflexia. Laboratory findings revealed that the erythrocyte sedimentation rate was elevated to 46mm/hr, rheumatoid factor (RF) to 83.1IU/ml and CRP to 3.7mg/dl. Her blood sugar was high and she was diagnosed as having diabetes mellitus. Cervical X ray film showed atlanto-axial subluxation. A pseudotumor around the odontoid process bulging into the spinal canal and compression of the upper cervical cord was observed by MRI. In spite of administration of bucillamine (100mg/day), the size of pseudotumor did not change. Methotrexate (MTX) at a dose of 5mg/week was started in February 1991 and the pseudotumor decreased in size with a concurrent reduction of ESR, RF and CRP. However, the high intensity lesion by T2 weighed image did not change and dysesthesia persisted. The pseudotumor was thought to be due to pannus and it was revealed that MTX was effective for reduction. The persistent dysesthesia was probably due to the degeneration of the upper cervical cord, although diabetic neuropathy may also have played a role.

Aged↗

PubMed1992

Structure-activity relationship for ETB agonism in truncated endothelin-1 analogs.

The essential part of the ETB-selective agonist N-acetyl-GluAlaValTyrPheAlaHisLeuAspIleIleTrp (N-Ac-4AlaET-1(10-21)) for ETB agonism was studied by single amino acid replacement. Single L-alanine substitutions at positions 14, 17, 20 and 21 and the corresponding D-amino acid substitutions at positions 14 and 16-21 resulted in remarkable decreases in ETB binding activity. Furthermore, these analogs elicited endothelium-dependent vasorelaxation in parallel with ETB binding activity. These data indicate that the amino acid residues of Phe14, Leu17, Ile20 and Trp21 and the backbone structure at Phe14 and His16-Trp21 in ET-1 are important for ETB agonism.

Alanine↗

PubMed1991

Response to and expression of amphiregulin by ovarian carcinoma and normal ovarian surface epithelial cells: nuclear localization of endogenous amphiregulin.

Amphiregulin (AR) is a polypeptide growth regulator which has sequence homology to the epidermal growth factor-related family of ligands and contains putative nuclear targeting sequences. Human ovarian carcinoma cell lines and their normal counterparts, ovarian surface epithelial cells (OSEs), were assessed for their ability to respond to and express AR. Addition of exogenous AR (8-200 pM) inhibited the growth of 2 of 3 OSE specimens and 3 of the 6 carcinoma cell lines indicating that AR has the potential to inhibit the growth of normal cells, in addition to carcinoma cells. In contrast, concentrations of AR ranging from 1-5 nM stimulated the growth of all 3 of the OSEs and 4 of the 6 carcinoma cell lines. Immunocytochemical staining of the cells using antipeptide antibodies directed against residues 8-26 of AR indicated that all cells expressed AR and that the staining was localized to the nucleus. The nuclear staining of AR was concentrated in the nucleolus of the carcinoma cells, whereas the staining was diffuse in the nucleus of the OSEs. These results suggest that AR may play a growth regulatory role in the nucleus of cells and this role may be different in normal and malignant epithelial cells.

Amphiregulin↗

PubMed1991

Differential expression of epidermal growth factor-related proteins in human colorectal tumors.

Amphiregulin (AR) and cripto are proteins that are structurally related to epidermal growth factor (EGF) and transforming growth factor alpha (TGF-alpha). AR is also functionally related to this family of growth regulatory molecules and is able to bind and activate the 170-kDa EGF receptor (EGFR). Human EGFR-3 (HER3)/ERBB3 is a recently identified protein related to the EGFR that is widely expressed in breast carcinomas and is a candidate receptor for EGF-like growth factors. Differential expression of these putative ligands and receptors in transformed cells suggests that they may function in an autocrine manner to regulate tumor cell growth. Specific mRNA transcripts for TGF-alpha [4.8 kilobases (kb)], AR (1.4 kb), cripto (2.2 kb), and HER3 (6.2 kb) were expressed in a majority of human colon cancer cell lines. HER3 mRNA was detected in 55% of primary or metastatic human colorectal carcinomas but in only 22% of normal colon mucosa and 32% of normal liver samples. In contrast, cripto and AR mRNA were expressed in 60-70% of primary or metastatic human colorectal cancers but in only 2-7% of normal human colonic mucosa. Immunostaining also detected AR protein in primary and metastatic colorectal tumors but not in normal colon or uninvolved liver. These findings suggest that cripto and AR may be useful markers to discriminate between normal and malignant colonic epithelium and may provide a selective growth advantage for colorectal carcinomas.

Actins↗

PubMed1991

[Ala1,3,11,15]endothelin-1 analogs with ETB agonistic activity.

A linear peptide analog of endothelin (ET)-1, [Ala1,3,11,15]ET-1 (4AlaET-1), and its truncated peptide analogs were synthesized to study the structural requirements of ET-1 for the recognition of ETs-nonselective ETB receptors. ET-1 exhibited sub-nanomolar binding to two distinct ET receptor subtypes (ETA and ETB), but 4AlaET-1 bound to ETB with an affinity 1,700 times higher than that seen during binding to ETA. The truncated linear peptides 4AlaET-1(6-21), 4AlaET-1(8-21) and N-acetyl-4AlaET-1(10-21) still had high affinity for ETB, whereas 4AlaET-1(6-20) and 4AlaET-1(11-21) displayed remarkably reduced affinity for ETB. Therefore, ET-1 requires the Glu10-Trp21 sequence for ETB binding, but not the disulfide bridges. These ETB-binding peptides elicit endothelium-dependent vasorelaxation of porcine pulmonary arteries in parallel with the binding affinity for ETB, suggesting that they are ETB agonists.

Amino Acid Sequence↗

PubMed1991

An endothelin receptor (ETA) antagonist isolated from Streptomyces misakiensis.

A competitive endothelin (ET) antagonist, BE-18257B, was isolated from the fermentation products of Streptomyces misakiensis. It is a novel cyclic pentapeptide, cyclo(-D-Glu-L-Ala-allo-D-Ile-L-Leu-D-Trp-), and binds to ETA receptors (ET-1 selective) in cardiovascular tissues, but not to ETB receptors (equally sensitive to isopeptides of ET family) in kidney, adrenal gland and cerebellum tissues. BE-18257B also antagonizes ET-1-induced vasoconstriction in rabbit iliac artery and pressor action in rats. Thus it is a selective ETA antagonist and should provide a valuable tool for elucidation of the pharmacological and pathophysiological roles of ET-1.

Animals↗

PubMed1991

Expression of transforming growth factor alpha (TGF alpha) in breast cancer.

Transforming growth factor alpha (TGF alpha) is one growth factor that has been circumstantially implicated in regulating the autocrine growth of breast cancer cells. Expression of TGF alpha can be modulated by activated cellular protooncogenes such as ras and by estrogens. For example, the epidermal growth factor (EGF)-responsive normal NOG-8 mouse and human MCF-10A mammary epithelial cell lines can be transformed with either a point-mutated c-Ha-ras protooncogene or with a normal or point-mutated c-neu (erbB-2) protooncogene. In ras transformed NOG-8 and MCF-10A cells but not in neu transformed cells there is a loss in or an attenuated response to the mitogenic effects of EGF. This response may be due in part to an enhanced production of endogenous TGF alpha that is coordinately and temporally linked to the expression of the activated ras gene and to the acquisition of transformation-associated properties in these cells. TGF alpha mRNA and TGF alpha protein can also be detected in approximately 50-70% of primary human breast tumors. In addition, approximately 2- to 3-fold higher levels of biologically active and immunoreactive TGF alpha can also be detected in the pleural effusions from breast cancer patients as compared with the TGF alpha levels in the serous effusions of noncancer patients. Over-expression of a full-length TGF alpha cDNA in NOG-8 and MCF-10A cells is capable of transforming these cells. Finally, expression of TGF alpha mRNA and production of biologically active TGF alpha protein is also found in normal rodent and human mammary epithelial cells.

Animals↗

PubMed1991

Two endothelin receptor subtypes in porcine arteries.

Endothelin-1 (ET-1) and ET-3 caused constrictions of endothelium-denuded porcine coronary artery strips with different concentration-response curves: a typical sigmoidal curve to ET-1 and a two-phase sigmoidal curve to ET-3. Binding assays using a membrane preparation demonstrated different Bmax values for [125I]ET-1 and [125I]ET-3 binding. In addition, [125I]ET-1 binding was inhibited by ET-1 and ET-3 with different potencies (ET-1 greater than ET-3), while [125I]ET-3 binding was inhibited by both ETs equally. From these results, two distinct ET receptor subtypes were proposed in the artery; site 1 (selective to ET-1) and site 2 (equally sensitive to both ETs). However, only site 1 was identified on cultured arterial smooth muscle cells (VSMCs) by the binding assay, and this was confirmed since only ET-1 (not ET-3) caused a significant increase in the intracellular free Ca2+ concentration. Therefore, it seems likely that vasoconstriction is mediated via the binding of ET-1 to site 1 (VSMCs) and site 2 (non-VSMCs), or the binding of ET-3 to site 2 (non-VSMCs). Furthermore, site 2 was predominant in nonvascular tissues such as lung, kidney, and cerebellum, thereby suggesting that site 1 may exist in limited tissues such as VSMCs.

Animals↗

PubMed1991

Appearance of a carcinoid-like pattern in rat hepatic tumors induced by 3'-methyl-4-dimethyl-aminoazobenzene.

This study investigated the histological distribution of argyrophilic cells in experimental hepatic neoplasms, the number of these cells, and the proportion of neoplasms with such cells. Seventy 6-week-old male Donryu rats were given a 0.06% 3'-methyl-4-dimethyl-aminoazobenzene (3'-MeDAB) diet for 10 weeks, followed by an ordinary diet for an additional 10 weeks. Of the 70 rats, 50 were used for this investigation; 29 had hepatic tumors, 18 had cholangiofibrosis, and the other three had oval cell proliferation only. Hepatic tissues were stained with Grimelius and Fontana-Masson stains as well as routine hematoxylin-eosin stain. Argyrophilic cells were found in the hepatic neoplasms of 8 rats without argentaffin cells, while cholangiofibrosis was associated with argentaffin cells in almost all cases. Of the 8 rats with argyrophilic cells, three had an abundant population of these cells. The argyrophilic cells were found in areas of the neoplasms with a glandular, trabecular, tubular, or poorly differentiated pattern. Electron microscopy revealed that the neoplastic cells with a positive argyrophil reaction contained small round electron-dense endocrine granules. In addition, in the areas of cholangiofibrosis, two different types of gut endocrine cells were present (G and EC cells). These results suggest that 3'-MeDAB might induce hepatic carcinoid under certain conditions, though we have yet to confirm the development of a pure hepatic carcinoid due to this substance.

Animals↗

PubMed1991

Expression of cripto, a novel gene of the epidermal growth factor family, in human gastrointestinal carcinomas.

The expression of mRNA for cripto gene, a novel transforming gene of the epidermal growth factor family, was examined in 20 alimentary tract carcinoma cell lines, 60 surgically resected tumor tissues and their adjacent normal mucosas. Although the cripto mRNA was not detected in esophageal carcinomas or in normal mucosas, it was detected in gastric and colorectal carcinomas. In gastric carcinomas, 2.2 kb cripto mRNA was detected in one cell line, all the gastric carcinoma tissues and their adjacent normal mucosas. Of 23 gastric tumor tissues 8 (34.8%) exhibited a higher mRNA level than normal gastric mucosas. cripto mRNA was detected in 2 out of 6 colorectal carcinoma cell lines. Interestingly, 18 (81.8%) out of 22 colorectal carcinoma specimens expressed a higher level of cripto mRNA than that in normal mucosas. The level of the expression was higher than that in gastric carcinoma tissues. The expression was also correlated to tumor stage of colorectal carcinomas.

Adult↗

PubMed1991

Regulation by estrogen through the 5'-flanking region of the transforming growth factor alpha gene.

Expression of transforming growth factor alpha (TGF alpha) mRNA and protein can be stimulated by estrogens such as 17 beta-estradiol (E2) in estrogen-responsive rodent and human breast cancer cells. To ascertain if E2 can directly regulate TGF alpha expression through the 5'-flanking region of the human TGF alpha gene, E2-responsive MCF-7 or ZR-75-1 human breast cancer cells or E2-nonresponsive MDA-MB-231 breast cancer cells were transiently transfected with a plasmid containing an 1140-base pair (bp) Sac-I fragment of the TGF alpha 5'-flanking region ligated to the chloramphenicol acetyltransferase (CAT) gene. Cells that were transfected and subsequently treated with physiological concentrations of E2 (10(-11)-10(-8) M) for 24 h exhibited a 2- to 10-fold increase in CAT activity. The E2 stimulation of CAT activity was dose-dependent with an increase first found at 10(-10) M E2. The increase in CAT activity could be detected within 24-36 h after the addition of E2. There was no significant change in CAT activity in transiently transfected MDA-MB-231 cells as mediated through the TGF alpha 5'-flanking region after E2 treatment. MCF-7 cells were also transiently transfected with different fragments of the TGF alpha 5'-flanking region ligated to the luciferase gene. In the absence of E2 treatment, no detectable luciferase activity was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗