Genistein suppresses adhesion-induced protein tyrosine phosphorylation and invasion of B16-BL6 melanoma cells

Protein tyrosine phosphorylation occurs as one of the earlier events in cancer cell-extracellular matrix (ECM) interaction. With immunoblot analysis and immunofluorescence microscopy, genistein was found to suppress the tyrosine phosphorylation of proteins located at the cell periphery, including a 125 kDa protein, when B16-BL6 melanoma cells attached to and interacted with ECM. When accompanied by the suppression of adhesion-induced protein tyrosine phosphorylation, the invasive potential of B16-BL6 cells through reconstituted basement membrane was decreased significantly. However, neither adhesive capability nor cell growth was significantly affected by genistein. Therefore, the interruption of cancer cell-ECM interaction by suppression of protein tyrosine phosphorylation may contribute to invasion prevention of genistein.

[Protective effects of d-, l-, and dl-3-n-butylphthalide on neuronal damage induced by hypoxia/hypoglycemia in cultured rat cortical neurons]

The effects of l-3-n-butylphthalide(l-NBP) and d-3-n-butylphthalide(d-NBP) on hypoxia/hypoglycemia-induced cytotoxicity in primary cultured rat cortical neurons were studied. l-NBP and d-NBP(1-100 mumol.L-1) were shown to inhibit hypoxia/hypoglycemia-induced LDH release, decrease the percent of cell death and improve the damaged cellular morphology at 10 mumol.L-1 concentration. In addition, l-NBP, d-NBP and dl-NBP were also found to significantly reduce the liberation of polyribosomes from the neuronal rough endoplasmic reticulum and disaggregation of polyribosomes induced by hypoxia/hypoglycemia. These data suggest that l-NBP, d-NBP and dl-NBP can remarkably protect cultured neurons against hypoxia/hypoglycemia induced damage.

The origin of differences in the physical properties of the equilibrium forms of cytochrome b5 revealed through high-resolution NMR structures and backbone dynamic analyses

On the basis of a comparison of high-resolution solution structures calculated for both equilibrium forms of rat ferrocytochrome b5, differences in reduction potential and thermodyanmic stability have been characterized in terms of significant structural and dynamic differences between the two forms. The dominant difference between A and B conformations has long been known to be due to a 180 degrees rotation of the heme in the binding pocket about an axis defined by the alpha- and gamma-meso carbons, however, the B form has not been structurally characterized until now. The most significant differences observed between the two forms were the presence of a hydrogen bond between the 7-propionate and the S64 amide in the A form but not the B form and surprisingly a displacement of the heme out of the binding pocket by 0.9 A in the B form relative to the A form. The magnitude of other factors which could contribute to the known difference in reduction potentials in the bovine protein [Walker, F. A., Emrick, D., Rivera, J. E., Hanquet, B. J., and Buttlaire, D. H. (1988) J. Am. Chem. Soc. 110, 6234-6240], such as differences in the orientation of the axial imidazoles and differences in hydrogen bond strength to the imidazoles, have been evaluated. The dominant effector of the reduction potential would appear to be the lack of the hydrogen bond to the S64 amide in the B form which frees up the propionate to charge stabilize the iron in the oxidized state and thus lower the reduction potential of the B form. The structure we report for the A form, based on heteronuclear NMR restraints, involving a total of 1288 restraints strongly resembles both the X-ray crystal structure of the bovine protein and a recently reported structure for the A form of the rat protein based on homonuclear data alone [Banci, L., Bertini, I., Ferroni, F., and Rosato, A. (1997) Eur. J. Biochem. 249, 270-279]. The rmsd for the backbone atoms of the A form is 0.54 A (0.92 A for all non-hydrogens). The rmsd for the backbone of the B form is 0.51 A (0. 90 A for all non-hydrogen atoms). An analysis of backbone dynamics based on a model-free analysis of 15N relaxation data, which incorporated axially symmetric diffusion tensor modeling of the cytochrome, indicates that the protein is more rigid in the reduced state relative to the oxidized state, based on a comparison with order parameters reported for the bovine protein in the oxidized state [Kelly, G. P., Muskett, F. W., and Whitford, D. (1997) Eur. J. Biochem. 245, 349-354].

[Effects of d-3-n-butylphthalide and l-3-n-butylphthalide on extracellular no level and intracellular cGMP level in primary cultured rat cortical neurons]

The effects of l-3-n-butylphthalide(l-NBP) and d-3-n-butylphthalide(d-NBP) on extracellular nitric oxide (NO) levels and intracellular cyclic GMP (cGMP) levels were studied in primary cultured rat cortical neuronal cells. Nitric oxide and cGMP levels were measured by using spectrometry and radioimmunological analysis(RIA), respectively. The results showed that d-NBP (0.1-100 mumol: L-1) markedly increased extracellular NO levels and intracellular cGMP levels in primary cultured neurons that were exposed for 10 h to hypoxic/hypoglycemic, N-methyl-D-aspartate (NMDA), or KCl media. On the contrary, l-NBP(0.1-100 mumol.L-1) significantly decreased extracellular NO levels and intracellular cGMP levels. It is suggested that there is a contrary effect of d-NBP and l-NBP on NO release and cGMP production induced by hypoxia/hypoglycemia, NMDA, or KCl.

[Study on changes of plasma substance P in essential hypertension with left ventricular hypertrophy patients and the effect of promoting blood circulation and eliminating phlegm]

OBJECTIVE

Exploring the relationship between the plasma substance P(SP) and essential hypertension with left ventricular hypertrophy (EH-LVH) and the effect of promoting blood circulation and eliminating phlegm.

METHODS

Before and after treatment, the changes of SP in patients wiith EH-LVH were measured by radioimmunoassay. Meanwhile, the changes of plasma renin activity (PRA), angiotension II (Ang II), left ventricular mass index (LVMI) and mean arterial pressure (MAP) were measured.

RESULTS

The level of plasma SP in patients with EH-LVH was markedly lower than that of patients without EH-NLVH and healthy subjects (P < 0.001); the levels of PRA and Ang II were higher than those in control group (P < 0.01 or < 0.05). After treatment, the level of SP was significantly increased, while LVMI, MAP, PRA and Ang II were significantly decrease (P < 0.01 or < 0.05). The levels between SP and LVMI, MAP, PRA, Ang II were markedly negative correlated (P < 0.01) while levels between LVMI and PRA, Ang II were markedly positive correlated.

CONCLUSIONS

The SP may be involved in the pathogenesis of EH-LVH; the mechanism of promoting blood circulation and eliminating phlegm reversing LVH might be related to its increasing the plasma SP.

Nuclear localization domain of thyroid transcription factor-1 in respiratory epithelial cells

Thyroid transcription factor-1 (TITF-1) is a homeodomain containing transcription factor that binds to and selectively activates the expression of genes in thyroid and pulmonary epithelial cells. TITF-1 plays a critical role in gene expression and in organogenesis of lung and thyroid. In the present work, epitope-tagged TITF-1 proteins were used to identify the regions of the TITF-1 polypeptide that mediate nuclear localization and transcriptional activity in human lung adenocarcinoma cells. A series of TITF-1-flag deletion mutants was generated and transfected into H441 cells to determine amino acid sequences involved in translocation to the nucleus. Transfection of the TITF-1-flag mutants demonstrated that a nuclear localization signal (NLS) sequence, located at the N-terminus of the homeodomain, is critical for nuclear targeting. The NLS was essential but not sufficient for translocation of TITF-1 to the nucleus, since deletion of the homeodomain itself also blocked nuclear translocation in the presence of NLS. Deletion of the N-terminal transactivation domain of TITF-1 completely abolished its transcriptional activation on the human surfactant protein-B promoter, and deletion of the C-terminal domain partially reduced its stimulatory activity. Nuclear translocation of TITF-1 depends on both an NLS and the homeodomain of the polypeptide. Both C- and N-terminal regions of TITF-1 are involved in transactivation of surfactant protein B gene expression in pulmonary cells.

Hepatocyte nuclear factor-3beta limits cellular diversity in the developing respiratory epithelium and alters lung morphogenesis in vivo

Hepatocyte nuclear factor-3beta (HNF-3beta), a nuclear protein of the winged helix family of transcription factors, is known to play a critical role in the formation of the embryonic node, notochord, and foregut endoderm. HNF-3beta influences the expression of a number of target genes in the respiratory epithelium, activating transcription of thyroid transcription factor-1, surfactant protein-B and clara cell secretory protein. In order to discern the role of HNF-3beta in differentiation and gene expression in the lung, HNF-3beta was expressed in developing respiratory epithelial cells of transgenic mice, under the control of the human surfactant protein C gene promoter. Pulmonary abnormalities were observed in the lungs of fetal mice bearing the HNF-3beta transgene. Differentiation of distal respiratory epithelial cells was arrested in the early pseudoglandular stage. Branching morphogenesis and vasculogenesis were markedly disrupted in association with decreased E-cadherin and vascular endothelial growth factor expression. HNF-3beta limits cellular diversity of developing respiratory epithelium and alters lung morphogenesis in vivo, suggesting that precise temporal-spatial regulation of HNF-3beta expression is critical for respiratory epithelial cell differentiation and lung morphogenesis.

Protein kinase A activation of the surfactant protein B gene is mediated by phosphorylation of thyroid transcription factor 1

Thyroid transcription factor 1 (TTF-1) is a homeodomain-containing nuclear transcription factor expressed in epithelial cells of the lung and thyroid. TTF-1 binds to and activates the transcription of genes expressed selectively in the respiratory epithelium including pulmonary surfactant A, B, C and Clara cell secretory protein. Transfection with a plasmid encoding the cyclic AMP-dependent protein kinase (protein kinase A; PKA) catalytic subunit, Cat-beta, stimulated the phosphorylation of a TTF-1-flag fusion protein 6-7-fold in H441 pulmonary adenocarcinoma cells. Recombinant TTF-1 was phosphorylated by purified PKA catalytic subunit in the presence of [gamma-32P]ATP. PKA catalytic subunit family members, Cat-alpha and Cat-beta, markedly enhanced the transcriptional activation of surfactant B gene promoters by TTF-1 in vitro. Peptide mapping was used to identify a PKA phosphorylation site at the NH2 terminus of TTF-1. A 17-amino acid synthetic peptide comprising this site completely inhibited the PKA-dependent phosphorylation of TTF-1 in vitro. A substitution mutation of TTF-1 (Thr9 two head right arrow Ala) abolished phosphorylation by PKA and reduced transactivation of the surfactant B gene promoter. Transfection with a plasmid encoding the cAMP regulatory element binding factor inhibited transcriptional activity of the surfactant protein B gene promoter. Phosphorylation of TTF-1 mediates PKA-dependent activation of surfactant protein B gene transcription.

A role for the divergent actin gene, ACT2, in nuclear pore structure and function

We have identified a temperature-sensitive allele of the yeast divergent actin gene ACT2, act2-1, which displays defects in nuclear pore complex (NPC) structure and nuclear import at the restrictive temperature. Although defective in nuclear import, act2-1 cells still selectively retain reporter proteins in the nucleus, and by indirect immunofluorescence the actin cytoskeleton appears normal. Previous studies in Acanthamoeba and Saccharomyces cerevisiae reported that the cellular location of Act2p partially overlaps that of conventional actin, indicating that it has a cytoskeletal function. In this study, both immunofluorescence localization and cellular fractionation of different epitope-tagged versions of Act2p also reveal an association with the nucleus, suggesting an independent nuclear function for Act2p. Analysis of act2-1 by electron microscopy, 30 min after a shift to the restrictive temperature (37 degrees C), reveals a striking aberration in NPC morphology; NPCs appear as abnormal densities on either side of, rather than spanning, the nuclear envelope. Immunoelectron microscopy confirms that these densities contain XFXFG nucleoporins. act2-1 is synthetically lethal in combination with a deletion in the XFXFG nucleoporin gene, NUP1, or a mutation in the nuclear localization sequence receptor gene, SRP1. Act2p and Srp1p co-immunoprecipitate, suggesting that the proteins exist in a complex. Together our data argue that Act2p plays an important role in NPC structure and function.

Characterization of a site-directed mutant of cytochrome b5 designed to alter axial imidazole ligand plane orientation

Mutants of cytochrome b5 were designed to achieve reorientation of individual axial imidazole ligands. The orientation of the axial ligand planes is thought to modulate the reduction potential of bis(imidazole) axially ligated heme proteins. The A67V mutation achieved this goal through the substitution of a bulkier, hydrophobic ligand for a residue, in the sterically hindered hydrophobic heme binding pocket. Solution structures of mutant and wild-type proteins in the region of the mutation were calculated using restraints obtained from 1H and 15N 2D homonuclear and heteronuclear NMR spectra and 1H-15N 3D heteronuclear NMR spectra. More than 10 restraints per residue were used in the refinement of both structures. Average local rmsd for 20 refined structures was 0.30 A for the wild-type structure and 0.38 A for the A67V mutant. The transfer of amide proton resonance assignments from wild-type to the mutant protein was achieved through overlays of 15N-1H heteronuclear correlation spectra of the reduced proteins. Side chain assignments and sequential assignments were established using conventional assignment strategies. Calculation of the orientation of the components of the anisotropic paramagnetic susceptibility tensor, using methods similar to procedures applied to the wild-type protein, shows that the orientation of the in-plane components are identical in the wild-type and mutant proteins. However, the orientation of the z-component of the susceptibility tensor calculated for the mutant protein differs by 17 degrees for the A-form and by 11 degrees for the B-form from the orientation calculated for the wild-type protein. The rotation of the z-component of the susceptibility tensor (toward the delta meso proton) is in the same direction and is of the same magnitude as the rotation of the H63 imidazole ring induced by mutation.

The culture of chicken embryo fibroblast cells on microcarriers to produce infectious bursal disease virus

The cultures of chicken embryo fibroblast (CEF) cells in flasks, spinner bottles, and bioreactors were studied. The growth and metabolism characteristics of CEF cells and the feasibility of the CEF cell culture in bioreactor were investigated. The plating process of the CEF cells on GT-2 microcarriers in spinner bottles was studied, and a plating kinetic model was presented. The culture of CEF cells in 1.5 L CelliGen bioreactor to produce infectious bursal disease virus (IBDV) had met success. Whereas the additive microcarriers were fed during the culture, the cell density was increased 10 times as against seed cells adhering to microcarriers and the virus titer was as high as 7.5. All the aforementioned experimental results have laid the foundation for high density culture of CEF cells and process scale-up.

Suppression of adhesion-induced protein tyrosine phosphorylation decreases invasive and metastatic potentials of B16-BL6 melanoma cells by protein tyrosine kinase inhibitor genistein

Protein tyrosine kinase (PTK) appears to be involved in the activation of signaling during cell attachment to and spreading on extracellular matrix (ECM) in the metastatic cascade. To verify the assumption that PTK inhibitors might impair ECM signaling and prevent cancer metastasis, the highly metastatic B16-BL6 mouse melanoma cells were exposed to the PTK inhibitor genistein for 3 days. The ability of the cells to invade through reconstituted basement membrane (Matrigel) and to establish experimental pulmonary metastatic foci in C57BL/6 mice decreased after genistein exposure. The genistein-treated cells were also prevented from attaching to Matrigel and spread extremely poorly on the ECM substratum. Immunoblot analysis showed that tyrosine phosphorylation of a 125-kD protein in response to cell spreading on Matrigel was suppressed in the genistein-treated cells. Adhesion-induced protein tyrosine phosphorylation represents the earlier and specific event in the activation of ECM signaling, so this result implied ECM signaling was impaired in the treated cells. With immunofluorescence microscopy, the adhesion-induced tyrosine phosphorylated proteins were located at the pericytoplasms of well-spread cells, but not at the periphery of poorly spread genistein-treated cells. Therefore, this paper suggests that genistein might impair ECM signaling and subsequently prevent cancer cells from spreading well and invading or establishing metastasis through the suppression of adhesion-induced protein tyrosine phosphorylation. PTKs and adhesion-induced protein tyrosine phosphorylation might play a role in the control of invasion and metastasis.

[Lead exposure level in umbilical cord blood and its related factors]

Six hundred and five specimens of umbilical cord blood were collected from Yangpu District, Shanghai, and blood lead levels were determined with graphite stove atom absorption spectrophotometry in 348 of them to study fetal exposure to lead and its related factors in the people of Shanghai. Survey on household social and environmental health status was conducted in families with the babies whose umbilical cord blood lead were above the 70th percentile and below the 30th percentile with a face-to-face questionnaire. Data were analyzed with multiple regression for the factors which affected the lead level in umbilical cord blood significantly. Results showed that blood lead levels in 348 cases were normally distributed, with a range of 0.08 to 0.84 mumol/L, a mean of 0.44 mumol/L and a standard deviation of 0.15 mumol/L. Specimens with cord blood lead level exceeding the safety criteria of 0.48 mumol/L accounted for 40.8 percent of the total. The study also found that passive smoking during pregnancy, exposure to lead in family members, one's living room adjacent to the major traffic roads, pollution by coal-burning smoke in the environment of one's residence, use of coal as domestic fuel, and eating preserved eggs during pregnancy all were risk factors for lead exposure. Multiple logistic regression analysis revealed that contribution of passive smoking to cord blood lead level was still statistically significant after adjusting other confounding factors. It concluded that environmental lead pollution could cause ad-verse effects on fetal development.

The calmodulin-dependent phosphodiesterase gene PDE1C encodes several functionally different splice variants in a tissue-specific manner

We report here the identification of cDNAs for three new mouse PDE1C splice variants and the characterization of their kinetics, regulation by Ca2+, sensitivities to inhibitors, and tissue/cellular expression patterns. Sequence analysis indicated that these three cDNAs (PDE1C1, PDE1C4, and PDE1C5), together with our previously reported PDE1C2 and PDE1C3, are alternative splice products of the PDE1C gene. The results from RNase protection analysis and in situ hybridization indicated that the expression of the different PDE1C splice variants is differentially regulated in a tissue/cell-specific manner. Particularly, high levels of PDE1C mRNAs were found in the olfactory epithelium, testis, and several regions of mouse brain such as cerebellar granule cells. All of these splice variants have similar kinetic properties, showing high affinities and approximately the same relative Vmax values for both cAMP and cGMP. However, they responded to Ca2+ stimulation differently. In addition, they show different sensitivities to the calmodulin-dependent phosphodiesterase inhibitors, KS505a and SCH51866. Substrate competition experiments suggested the presence of only one catalytic site on these PDE1C isozymes for both cAMP and cGMP. In summary, these findings suggest that the PDE1C gene undergoes tissue-specific alternative splicing that generates structurally and functionally diverse gene products.

Intranasal stimulation of long-lasting immunity against aerosol ricin challenge with ricin toxoid vaccine encapsulated in polymeric microspheres

Intranasal (i.n.) immunization with ricin toxoid (RT) vaccine encapsulated in poly (lactide-co-glycolide) microspheres (RT-PLG-Ms) and poly (L-lactide) microspheres (RT-PLA-Ms) stimulated systemic and mucosal immune responses and protected mice from aerosolized ricin intoxication. High titers of anti-ricin IgG2a were stimulated in the serum of mice with one or two doses of RT-Ms 6 weeks postimmunization. However, in the lungs, no IgG2a or total IgG was elicited either with RT-Ms or with aqueous RT. At 6 weeks postimmunization, a single dose of the RT-Ms stimulated secretory IgA (sIgA) in the lungs of four of six mice, but a second immunizing dose did not enhance the stimulation. A single dose of aqueous RT vaccine failed to stimulate sIgA in the lungs, while, a second dose induced sIgA in 50% of the mice. One or two i.n. doses of RT-Ms protected most of the mice against lethal aerosol-delivered ricin toxin 6 weeks postimmunization. In contrast, protection was absent or marginal after one or two doses of aqueous RT vaccine. In both studies, the protection against lethal aerosol challenge was significantly better with one dose of RT-Ms than with two doses of aqueous vaccine, which may be attributed to the induction of sIgA in the lungs and the serum. Duration of the IgG2a and IgA in the serum, particularly that of IgG2a was much longer after the administration of RT-Ms than after the aqueous vaccine. The geometric mean IgG2a titers stimulated with two doses of RT-Ms remained high during 40 weeks postimmunization and were up to 25 times higher than the titers induced with aqueous RT vaccine. After 6 weeks, the IgG2a induced by two doses of aqueous vaccine was no longer detectable. Persistence of antibody response was predictive of efficacy. At 1 year postimmunization with two doses of RT-Ms, 100% of mice were protected against lethal ricin challenge. However, at the same time no protection was afforded by two doses of aqueous RT. The results of the present study consistently demonstrated the advantages of microencapsulated RT vaccine to stimulate effective and long-lasting protection by i.n. administration.

The interaction of a type A retroviral particle and class II human leukocyte antigen susceptibility genes in the pathogenesis of Graves' disease

We have previously reported that over 85% of patients with Graves' disease have detectable serum antibodies against a human intracisternal type A retroviral particle (HIAP), which are not present in age- and gender-matched controls, suggesting a role for HIAP in triggering the autoimmune process leading to Graves' disease. To investigate the interaction of this viral particle with genetic factors, 35 members of 3 kindreds, selected because of a high family prevalence of Graves' disease (a total of 11 members affected), were examined for clinical signs of thyroid dysfunction, goiter, and opthalmopathy. Thyroid function tests and autoimmune serological profiles were also obtained. In addition, subjects were tested for the presence of antibodies against HIAP by means of immunoblot analysis of their sera, and their human leukocyte antigen (HLA) class II alleles were determined by DNA methodology. Molecular genetic analyses enabled the detection of postulated HLA susceptibility haplotypes in each family. These families had 8, 4, and 5 members, respectively, with such apparent susceptibility genes and 11, 5, and 9 members, respectively, with immunological evidence of retroviral exposure. In the presence of both factors (codetected in a total of 15 members of the 3 kindreds), the incidence of Graves' disease was 100%, 67%, and 80%, respectively. One additional member of family B and 3 in family C with both viral and genetic susceptibility factors were found to have serological abnormalities and/or goiter and ocular signs consistent with evolving or preclinical Graves' disease. In families A and C, tight linkage between HLA haplotypes and Graves' disease was demonstrated in a manner consistent with recessive inheritance. The association between the occurrence of both anti-HIAP-I antibody positivity and HLA susceptibility and the presence of Graves' disease was highly significant (P < 0.001). The pathogenesis of Graves' disease in these families appears to be attributable to the interaction between the immune response to an intracisternal type A retroviral particle and immunogenetic susceptibility, leading to the autoimmune processes that underlie Graves' disease, with subsequent development of the characteristic features of the illness. Data from these families suggest that both of these factors are necessary for final disease expression. These results imply that serological evidence of retroviral exposure together with genetic HLA susceptibility are the two major predisposing factors underlying the pathogenesis of Graves' disease. Further studies will establish whether prospective identification of persons at risk for Graves' disease is possible by this means.

[Relationship between lead content in umbilical blood and neurobehavioral development in infants]

One hundred and thirty-two babies were selected and their umbilical blood lead level were determined as a marker to reflect their exposure, to study the diagnostic criteria for lead poisoning in young children. And, mental development index (MDI) and psychomotor development index (PDI) of three-month babies in Bayley scales of infant development were used as effective indicators to study levels of lead on their development. Results indicated that both MDI and PDI in infants with blood lead levels of greater than or equal to 0.48 mumol/L were obviously lower than those with less than 0.48 mumol/L. All children were divided into two groups (high-blood-lead and low-blood-lead) according to the cut-off values for blood lead of 0.72, 0.48, and 0.24 mumol/L, respectively, and the difference in MDI and PDI between the two groups decreased gradually with the cut-off value shifted down, and there was no difference in them between the two groups when the cut-off point lowering down to 0.24 mumol/L. Therefore, the authors recommended that a level of 0.48 mumol/L of blood lead be used as diagnostic criteria for lead poisoning in young children.

Automated capillary electrochromatography: reliability and reproducibility studies

The routine application of capillary electrochromatography (CEC) is demonstrated by incorporating 75 microns I.D. capillaries packed with 3 microns octadecylsilica (ODS) particles into a commercial CZE instrument. A mixture of several neutral compounds is separated into its components with an average efficiency up to 181 000 plates/m in less than 8 min. Hundreds of consecutive runs are performed over a period of weeks from which it is concluded that the reproducibility of the capacity factors is better than 2% and that CEC separations can be achieved in a reliable and routine manner.

Upstream enhancer activity in the human surfactant protein B gene is mediated by thyroid transcription factor 1

Surfactant protein B (SP-B) is selectively expressed in bronchiolar and alveolar epithelial cells of the lung. We identified an upstream enhancer located in the 5'-flanking region of the human SP-B gene (-439 to -331 base pair, hSP-B(-439/-331)) by deletion analysis of SP-B-luciferase constructs assessed in transfection assays in vitro. The element cis-activated the expression of an SV40 promoter-luciferase reporter gene in a human pulmonary adenocarcinoma cell line (H441-4). Three distinct binding sites for the nuclear transcription protein, thyroid transcription factor 1 (TTF-1), were identified, and the purified TTF-1 homeodomain was bound to bhe region of hSP-B(-439/-331). Co-transfection of H441-4 cells with the expression vector pCMV-TTF-1 trans-activated the native human SP-B promoter and the SV40 promoter fused with the SP-B enhancer. Mutations of the TTF-1 binding sites in the upstream enhancer blocked TTF-1 binding and transactivation activity. In summary, TTF-1 interacts with distinct proximal (-80 to -110) and distal (-439 to -331) cis-acting elements than regulate lung epithelial cell-specific transcription of the human SP-B gene.

Molecular cloning and characterization of a calmodulin-dependent phosphodiesterase enriched in olfactory sensory neurons

The sensing of an odorant by an animal must be a rapid but transient process, requiring an instant response and also a speedy termination of the signal. Previous biochemical and electrophysiological studies suggest that one or more phosphodiesterases (PDEs) may play an essential role in the rapid termination of the odorant-induced cAMP signal. Here we report the molecular cloning, expression, and characterization of a cDNA from rat olfactory epithelium that encodes a member of the calmodulin-dependent PDE family designated as PDE1C. This enzyme shows high affinity for cAMP and cGMP, having a Km for cAMP much lower than that of any other neuronal Ca2+/calmodulin-dependent PDE. The mRNA encoding this enzyme is highly enriched in olfactory epithelium and is not detected in six other tissues tested. However, RNase protection analyses indicate that other alternative splice variants related to this enzyme are expressed in several other tissues. Within the olfactory epithelium, this enzyme appears to be expressed exclusively in the sensory neurons. The high affinity for cAMP of this Ca2+/calmodulin-dependent PDE and the fact that its mRNA is highly concentrated in olfactory sensory neurons suggest an important role for it in a Ca(2+)-regulated olfactory signal termination.

Developmentally expressed Ca(2+)-sensitive adenylyl cyclase activity is disrupted in the brains of type I adenylyl cyclase mutant mice

The type I Ca(2+)-sensitive adenylyl cyclase has been implicated in several forms of synaptic plasticity in vertebrates. Mutant mice in which this enzyme was inactivated by targeted mutagenesis show deficient spatial memory and altered long term potentiation (Wu, Z. L., Thomas, S. A., Villacres, E. C., Xia, Z., Simmons, M. L., Chavkin, C., Palmiter, R. D., and Storm, D. R. (1995) Proc. Natl Acad Sci. U. S. A. 92, 220-224). Long term potentiation in the CA1 region of the rat hippocampus develops during the first 2 weeks after birth and reaches maximal expression at postnatal day 15 with a gradual decline at later stages of development. Here we report that Ca(2+)-stimulated adenylyl cyclase activity in rat hippocampus, cerebellum, and cortex increases significantly between postnatal days 1-16. This increase appears to be due to enhanced expression of type I adenylyl cyclase rather than type VIII adenylyl cyclase, the other adenylyl cyclase that is directly stimulated by Ca2+ and calmodulin. Type I adenylyl cyclase mRNA in the hippocampus increased 7-fold during this developmental period. The developmental expression of Ca(2+)-stimulated adenylyl cyclase activity in mouse brain was attenuated in mutant mice lacking type I adenylyl cyclase. Changes in expression of the type I adenylyl cyclase during the period of long term potentiation development are consistent with the hypothesis that this enzyme is important for neuroplasticity and spatial memory in vertebrates.

Two-dimensional imaging and three-dimensional reconstruction of low reflectivity surfaces by using the range-gating upconversion second-harmonic method

Three-dimensional images of objects with very low reflectivity are obtained through a nonlinear upconversion gating with amplified femtosecond laser pulses. The current sensitivity of 10(-10) of the incident pulse intensity can be improved by use of better nonlinear crystals and higher-intensity gating pulses. The intensity rejection ratio between two coherent pulses with a delay of a few millimeters between them is better than 2 orders of magnitude. The depth resolution is ~15 µm. The transverse resolution of 300 µm is mainly limited by the two-dimensional detector that was used.

Dependence of ricin toxoid vaccine efficacy on the structure of poly(lactide-co-glycolide) microparticle carriers

Biodegradable microparticles made of poly(lactide-co-glycolide) (PLG) were used for protracted and pulsed-release of the incorporated ricin toxoid (RT) vaccine to reduce the multiple immunization doses and the time required to induce complete protection against lethal aerosol-borne ricin challenge. The release rate of RT encapsulated in PLG microparticles was controlled by polymer selection and varying the preparation procedures, which allowed us to control microparticle size and the distribution of the vaccine in the polymeric matrix. PLG-microparticles in which RT vaccine was distributed heterogeneously in small pockets stimulated a rapid antibody response which was independent of the polymeric composition of the carriers. PLG-microparticles in which RT vaccine was distributed homogeneously throughout the polymeric matrix induced a slower antibody response, which depended on the polymeric composition of the carriers. Administration of RT in homogeneous microparticles made from 50/50 PLG or 100% polylactide stimulated two distinct anti-ricin IgG peaks, while RT in heterogeneous microparticles stimulated identical IgG peaks. An early (3 weeks) and long-lasting (1 year or longer) anti-ricin antibody response was evoked by a single administration of encapsulated RT vaccine when prepared by the above-mentioned conditions. In contrast, three administrations of the aqueous RT were required to stimulate similar antibody response. Reduction of immunization time from 6 to 4 weeks was achieved with RT encapsulated in small homogeneous microparticles but not with homogeneous large microparticles. These results demonstrated the usefulness of biodegradable microparticles to improve the efficacy of immunization with RT vaccine and probably many other vaccines as well.

Energy Dependence of Abstractive Versus Dissociative Chemisorption of Fluorine Molecules on the Silicon (111)-(7X7) Surface

Scanning tunneling microscopy and monoenergetic molecular beams have been used to obtain real-space atomic images of the competition between abstractive and dissociative chemisorption. The size distribution of Si-F adsorbates on the Si(111)-(7x7) surface was examined as a function of the incident translational energy of the F(2) molecules. For F(2) molecules with 0.03 electron volt of incident energy, the dominant adsorbate sites were isolated Si-F species. As an F(2) molecule with low translational energy collides with the surface, abstraction occurs and only one of the F atoms chemisorbs; the other is ejected into the gas phase. For F(2) molecules with 0.27 electron volt of incident energy, many adjacent Si-F adsorbates (dimer sites) were observed because F(2) molecules with high translational energy collide with the surface and chemisorb dissociatively so that both F atoms react to form adjacent Si-F adsorbates. For halogens with very high incident energy (0.5-electron volt Br(2)), dissociative chemisorption is the dominant adsorption mechanism and dimer sites account for nearly all adsorbates.

Peptide V: a VGF-derived neuropeptide purified from bovine posterior pituitary

The objective of this study was to purify PRL-releasing factor (PRF) from the bovine posterior pituitary (PP) and determine its structure. Five hundred bovine PPs were acid extracted and fractionated using gel filtration chromatography followed by semipreparative and analytical HPLC. PRF activity was determined by an in vitro bioassay. After six chromatographic steps, a single peak with PRF activity was resolved. As determined by mass spectrometry and microsequencing, this peak contained a major peptide composed of 30 amino acids with a mol wt of 3708K. A synthetic peptide was then produced by solid-phase synthesis. When tested both in vivo and in vitro, the synthetic peptide lacked PRF activity. Further HPLC fractionation under different conditions resolved the synthetic peptide from a highly purified PRF activity. This indicated that the isolated peptide was coincidentally eluted with PRF during the purification. The major isolated peptide has 94% identity with a sequence at the C-terminus of a rat protein named VGF. VGF is a nerve growth factor-inducible protein that has been identified in PC12 cells and is localized in selected sites throughout the central nervous system. The isolated peptide has an Arg-Arg cleavage site at its junction within the VGF protein. Based on this information, we named this substance Peptide V (VGF-derived peptide). We postulate that Peptide V is: 1) a natural cleavage product of the VGF protein; 2) produced and processed either in the hypothalamus or within the pituitary proper, and 3) a releasable peptide that fulfills one or more endocrine functions.

[Significance of surgical treatment for bone metastasis from lung cancer]

To assess significance of surgical therapy for patients who had metastatic bone tumor from primary lung cancer, sites of recurrence in patients who underwent surgical resection for lung cancer lesions were analyzed. Clinical courses of patients who underwent surgical therapy for metastatic bone tumor were analyzed, too. 1) From 1985 to 1989, 88 patients died from lung cancer in our hospital who has underwent pulmonary resection for lung cancer lesions. Of these, 22 patients had metastatic bone tumor. Sixty patients died who had underwent complete resection for lung cancer lesions. In eight patients of these 60 cases, bone were first site of recurrence. Of these eight patients, length from pulmonary resection to detection of bone metastasis were 4-23 months. In the other hand, length from detection of bone metastasis of death were 3-24 months. There was no correlation between two length. All of these eight patients had another metastatic lesions at the time of death. 2) From 1985 to July 1993, twelve patients underwent surgical therapy for their bone metastasis of primary lung cancer. Of these, four had metastatic cancer in thoracic vertebral body, two had in clavicle, two had in rib, three had in femoral bone, another had in tibial bone. Objective of operation were improvement of paralysis or pain, prevention of fracture, and so on. Most cases succeeded to get improvement in a short time, but some cases got worse soon. Surgical treatment was effective to improve paralysis or pain, and to increase quality of life. But it can not be effective except appropriate management in a short time because another symptom raise soon.

[Hypothermic effects on uveal blood flow and postoperative inflammation in vitrectomy]

Hypothermic effects on uveal blood flow and postoperative inflammation were evaluated in experimental vitrectomy on albino rabbits. Solutions used for intraocular perfusion were maintained at 9 degrees C and 22 degrees C. Following the vitrectomy, the rabbits' intraocular spaces were irrigated for 60 minutes. The temperature at various sites and the uveal blood flow were measured before and during the procedure. Aqueous protein concentrations were checked on postoperative days 1, 7, and 14. Another solution maintained at 37 degrees C was used as a control. There was a larger decrease in temperature at the retina than there was at the choroid and the ciliary body. Blood flow at the ciliary body decreased to 76.0% and 77.0% at the choroid after 60 minutes of irrigation at 9 degrees C. The decrease at 22 degrees C were 91.0% and 88.3%, respectively. Aqueous protein concentrations at both 9 degrees C and 22 degrees C were significantly lower than at 37 degrees C on the first postoperative day in the eyes irrigated for 60 minutes. In the eyes irrigated for 30 minutes, however, no significant differences were seen. Hypothermia during a prolonged vitrectomy operation seems to decrease inflammation in early postoperative stages.

Detection of congenital cytomegalovirus infection by using chorionic villi of the early pregnancy and polymerase chain reaction

OBJECTIVE

To detect congenital cytomegalovirus (CMV) infection of chorionic villi in early pregnancy.

METHODS

Extraction of DNA of chorionic villi and amplification of the gene of major immediate-early (MIE) antigen of CMV using a polymerase chain reaction (PCR).

RESULTS

Sixty-eight specimens of chorionic villi and 16 specimens were positive for CMV infection by PCR. The incidence of congenital CMV infection in the first trimester of pregnancy was 23.5%.

CONCLUSIONS

The risk of transmission of CMV from mother to fetus in early pregnancy is very high and potential CMV carriers may transmit CMV to their fetus in early pregnancy.

Differential expression of the 61 kDa and 63 kDa calmodulin-dependent phosphodiesterases in the mouse brain

Based on their relative abundance and regulation by Ca2+ and by phosphorylation in vitro, it is thought that the Ca2+/calmodulin-dependent phosphodiesterases (CaM-PDEs) are important modulators of cyclic nucleotide function in the brain. Two of the most abundant CaM-PDEs in the brain are the 61 kDa and 63 kDa isozymes. In this study, the regional and cellular expression of mRNA encoding these two different isoforms in mouse brain has been determined by in situ hybridization. The 63 kDa CaM-PDE mRNA has a wide-spread but uneven distribution. Very strong hybridization signals are present in the caudate-putamen, nucleus accumbens, olfactory tubercle, and dentate gyrus of the hippocampus. Somewhat lesser amounts of 63 kDa CaM-PDE mRNA are present in the olfactory bulb and piriform cortex. Weaker but still easily discernible hybridization signals are seen in several layers of the cerebral cortex, CA1 and CA3 regions of the hippocampus, amygdaloid nuclear complex, thalamus, hypothalamus, midbrain, brainstem, cerebellum, and spinal cord. A weak hybridization signal was detected in the globus pallidus of the basal ganglia. In general, the distribution of the 63 kDa CaM-PDE is very similar to that of dopamine receptors, suggesting that it may modulate dopamine function. In contrast, the 61 kDa CaM-PDE mRNA has a more limited and much different distribution, with the highest level of expression in the cerebral cortex and in the pyramidal cells of the hippocampus. A moderate hybridization signal was detected in the medial habenula and amygdaloid nuclear complex. In addition, small subsets of neurons in several other regions showed specific hybridization. Both PDE mRNAs appear to be localized exclusively in neuronal cell bodies. Their distinct distribution suggests important but different physiological roles for these two isozymes in the regional regulation of cyclic nucleotides in the CNS. Since these two isozymes are differentially phosphorylated by cAMP-dependent and Ca2+/CaM-dependent protein kinases, the differential expression also provides a potential mechanism by which these PDEs can differentially regulate cAMP and cGMP in different brain areas. The high expression levels in specific subsets of neurons also suggest that agents increasing Ca2+ in these neurons will increase the rate of cyclic nucleotide degradation.

Multiple regions of NSR1 are sufficient for accumulation of a fusion protein within the nucleolus

NSR1, a 67-kD nucleolar protein, was originally identified in our laboratory as a nuclear localization signal binding protein, and has subsequently been found to be involved in ribosome biogenesis. NSR1 has three regions: an acidic/serine-rich NH2 terminus, two RNA recognition motifs, and a glycine/arginine-rich COOH terminus. In this study we show that NSR1 itself has a bipartite nuclear localization sequence. Deletion of either basic amino acid stretch results in the mislocation of NSR1 to the cytoplasm. We further demonstrate that either of two regions, the NH2 terminus or both RNA recognition motifs, are sufficient to localize a bacterial protein, beta-galactosidase, to the nucleolus. Intensive deletion analysis has further defined a specific acidic/serine-rich region within the NH2 terminus as necessary for nucleolar accumulation rather than nucleolar targeting. In addition, deletion of either RNA recognition motif or point mutations in one of the RNP consensus octamers results in the mislocalization of a fusion protein within the nucleus. Although the glycine/arginine-rich region in the COOH terminus is not sufficient to bring beta-galactosidase to the nucleolus, our studies show that this domain is necessary for nucleolar accumulation when an RNP consensus octamer in one of the RNA recognition motifs is mutated. Our findings are consistent with the notion that nucleolar localization is a result of the binding interactions of various domains of NSR1 within the nucleolus rather than the presence of a specific nucleolar targeting signal.

Identification of a new interferon-alpha/beta-inducible DNA-binding protein that interacts with the regulatory element A of 2',5'-oligoadenylate synthetase ME-12 gene

A new interferon (IFN)-stimulated response factor (ISRF) has been identified in nuclear extracts of IFN-alpha/beta-treated murine BALB/c-3T3 fibroblasts by the mobility-shift electrophoresis assay. The factor, ISRF-2, displays murine 2',5'-oligoadenylate (2-5A) synthetase ME-12 gene 5' regulatory element A specificity and differs from the previously described IFN response element B-specific factor ISRF-1 in several aspects. ISRF-2 is restricted to the nucleus, whereas ISRF-1 exists in the cytoplasm and translocates into the nucleus upon treatment of cells with IFN-alpha/beta. The ionic strength requirement of ISRF-2 for maximal DNA-binding activity is lower than that of ISRF-1. The DNA-binding activity of ISRF-2, but not that of ISRF-1, is markedly suppressed by Mg2+. In common with ISRF-1, the phosphorylated form of ISRF-2 appears to be required for DNA-binding activity. A model is proposed for the mechanism whereby murine IFN-alpha/beta regulates 2-5A synthetase ME-12 gene expression.

Imaging with femtosecond pulses

An all-optical three-dimensional imaging system based on direct upconversion of depth-resolved images is described. Femtosecond gating of the signal provides a depth resolution in the microm range and a discrimination of the image against scattered light.

Molecular cloning and characterization of additional factors that bind to the interferon-alpha/beta response element B of the murine (2'-5')oligoadenylate synthetase ME-12 gene

The function of interferon (IFN) response elements (IREs) may be classified into two classes according to the location of the IRE in the polymerase II transcription promoter: located upstream of the core promoter, or located within the core promoter. Thus, the IRE-binding factors (IREBFs) can serve as sequence-specific transcription factors that activate IFN-inducible gene transcription and they can participate in preinitiation complex formation. In the murine and human (2'-5')oligoadenylate synthetase genes the IRE is located within the core promoter region. For this reason, it is important to isolate cDNAs encoding protein factors that can bind to this IRE and determine their functional roles in the regulation of expression of the IFN-inducible (2'-5')oligoadenylate synthetase gene. We have isolated three groups of cDNAs that encode IREBFs. Here we report on clone 38 cDNA, which contains an open reading frame encoding a protein of 277 amino acids that is designated IREBF-2. The C terminus of IREBF-2 is extremely proline-rich and contains a high percentage of short-armed amino acids. IREBF-2 shares marked similarity with some gene products of the herpes group of viruses. These gene products are potent transcription activators. IREBF-2 is constitutively expressed in BALB/c 3T3 cells.

Evaluation of the effect of PTCR/PTCA by 99mTc-MIBI myocardial imaging in acute and old myocardial infarction

This study is to clarify the ability of technetium-99m-Hexakis-2-methoxyisobutyl isonitrile(MIBI) myocardial scintigraphy for assessment of the effect of PTCR/PTCA as compared with conventional thallium-201 myocardial scintigraphy (201Tl). 99mTc-MIBI (740-888MBq) was injected before emergency PTCR/PTCA, and the initial imaging was performed immediately after PTCR/PTCA in 4 patients with acute myocardial infarction (AMI). On the other hand, in 2 patients with old myocardial infarction (OMI), 201Tl and MIBI myocardial imagings were performed before and one week after rescue PTCA. The defect area on the follow-up MIBI imaging was smaller than that on the initial MIBI imaging in 2 patients with successful emergency PTCR/PTCA. But in the other 2 AMI patients with unsuccessful reperfusion, the defect area did not significantly decrease after PTCR/PTCA. Reperfusion was successful in one of the two patients with OMI. In both the two patients with OMI, the MIBI defect area did not significantly decrease after rescue PTCA. MIBI myocardial scintigraphy is a useful noninvasive method for evaluating the effect of emergency PTCR/PTCA for myocardial salvage in patients with AMI, because MIBI is a kit type agent, and it does not redistribute.

[Hepatic carcinoma treated by hepatic arterial embolization using 131I and chemotherapeutic agent gelatin microspheres: report of 9 cases]

Nine patients with inoperable hepatoma were treated by using hepatic arterial embolization 131I and chemotherapeutic agent gelatin microsphere (131I-CA-GM). The emission CT after operation detected that the microspheres were concentrated on tumor area. The ratio between the radioactivity in tumor and that in liver was 4.1:1. A case died of ictopic embolization; the others survived 3, 4, 5, 19, 24, 7, 8, and 12 months respectively. Three of them were still alive. 131I-CA-GM has triple anticarcinogenic actions, including the arterial occlusion, targeting chemotherapy and internal radiation. The microspheres can selectively accumulate in the tumor artery and can be easily traced by gamma-camera or emission CT. 131I-CA-GM is a hopeful embolic agent for the treatment of liver cancer, but some problems about ectopic arterial embolization should be further studied.

Transversely pumped 11-pass amplifier for femtosecond optical pulses

An off-axis near-concentric interferometer is used for multiple passages through a small (2-mm-diameter) cylindrical volume of amplifying dye. The gain volume is pumped transversely by a copper-vapor laser, in a geometry designed for uniform pump. Pulse-to-pulse reproducibility better than 1% is obtained by operating with full saturation and using a solvent with a vanishing temperature-induced change in index of refraction (dn/dT = 0).

Pylorus and antroseromuscular flap-preserving gastrectomy--a new type of reconstruction after subtotal gastrectomy for treatment of gastroduodenal ulcer: clinical and experimental study

To avoid motility disturbances after Billroth gastrectomy, the authors designed pylorus and antroseromuscular flap-preserving subtotal gastrectomy (PAFPG). Results showed that gastric motility and emptying time of dogs after PAFPG were close to normal. PAFPG was applied to 125 consecutive patients with gastroduodenal ulcers (gastric ulcer, 15 patients; duodenal ulcer, 94 patients; and combined ulcers, 16 patients) confirmed by barium examination and fibro-gastroendoscopy. All patients recovered smoothly, none of them had postoperative complication. Gastric acid output reduction rates were as follows: basal acid output, 85.05% +/- 8.13%; maximal acid output, 81.76% +/- 10.85%; peak acid output, 81.42% +/- 10.15%. The incidence of postoperative enterogastric reflux (endoscopically) and the concentration of cholic acids in gastric juice were significantly lower in patients after PAFPG than after Billroth I or II gastrectomy. Results suggest that PAFPG reduced gastric acid outputs definitely and overcame adverse motility consequences after Billroth I or II gastrectomy desirably.

A method for studies of an El Tor-associated antigen of Vibrio cholerae O1

A method for studying the biotype El Tor associated mannose-sensitive haemagglutinin (MSHA) of V. cholerae O1 has been developed. By using crude MSHA adsorbed to chicken erythrocytes as solid phase antigen in an enzyme-linked immunosorbent assay (ELISA), antisera against V. cholerae of the El Tor biotype reacted in high titre with the MSHA-coated cells, whereas antisera against vibrios of the classical biotype did not bind significantly, i.e. in higher titre than pre-immune sera. The binding of anti-MSHA serum, or a monoclonal antibody against MSHA, to the MSHA-coated erythrocytes could be efficiently inhibited by crude MSHA as well as by El Tor vibrios whereas neither V. cholerae lipopolysaccharide nor different strains of classical vibrios had any inhibitory effect. These results support the existence of an El Tor-associated immunogen. They also suggest a possibility of determining antibodies against different haemagglutinins in ELISA without having access to purified antigens.

[An experimental study on hepatic arterial embolization with 131I-MMC-GM]

We designed a new gelatin microsphere (GM, 65 micron in diameter), which could combine with mitomycin C and 131I. The test in vitro showed that the GM had excellent drug release effect. Hepatic arterial embolization was carried out in 6 dogs with 131I-MMC-GM. The dogs survived from 4 to 28 days before being killed. Scintigraphy indicated that high radioactivity was concentrated in the liver, but was very low in the blood and thyroid. Pathologic study found that the GM was trapped in hepatic arterioles. The GM was eliminated by foreign body giant cells and the lumen of arterioles was occupied by granulations 14-28 days after operation. 131I-MMC-GM is a multiple anticancer agent which can exert triple action of targeting chemotherapy, internal radiotherapy and arterial embolization.

Effects of metals on the binding of protein factors to the mouse 2',5'-oligoadenylate synthetase ME-12 gene regulatory region

We have previously demonstrated that using mouse 2',5'-oligoadenylate synthetase (2-5A synthetase) gene (ME-12) regulatory region AB as a probe, at least six complexes (C1-C6) can be detected by the mobility shift electrophoresis assay with extracts of murine BALB/c-3T3 cells. The formation of these complexes is greatly influenced by different buffer conditions and the presence of metals. C1 and C4 signals are stronger in Tris-HCl buffer than in phosphate buffer in the absence of added metals. Both Na+ and Mg2+ facilitate C1, C3, and C4 formation. Na+ also facilitates C3 and C4 formation with the interferon (IFN) response element B. Na+ has little effect on C2 formation with the regulatory region AB, whereas presence of Mg2+ at low concentrations gives a strong C2 signal. A new band, C7, was detected in the presence of 50 or 100 mM Na+. A relatively high Mg2+ concentration is required for C5 formation and Mg2+ interferes with C6 and C7 formation. Cu2+ and Zn2+ markedly inhibit formation of most complexes. However, a new band forms in 0.15 mM Cu2+ when 10 mM Mg2+ was also present. Co2+ enhances C2b and C3 formation and inhibits C4 formation. Mn2+ enhances C3, C1, and C2 formation to different degrees and inhibits C4 formation. At 0.15 and 0.25 mM, Mn2+ generates a new band. In competition experiments between Cu2+ and Mg2+, Cu2+ strongly inhibited Mg2+ effects on complex formation, except that 0.15 or 0.25 mM Cu2+ enhanced the C2a and C2b signals.

Protein factors that bind to the murine 2',5'-oligoadenylate synthetase ME-12 gene 5' upstream regulatory region

The murine 2',5'-oligoadenylate synthetase ME-12 gene regulatory region AB forms six complexes with protein factors in murine BALB/c 3T3 cells as demonstrated by the mobility shift electrophoresis assay under the reaction conditions used. The complexes, designated C1-C6 in order of their decreasing electrophoretic mobility, showed three distinctive specificities with regulatory region AB, element A, and element B as probes or competing DNA: 1) C1 is region AB-specific (this complex did not form with either element A or B used alone or as a mixture); 2) C5 formed both with element A and element B; 3) C2, C3, C4, and C6 formed with element B, but not A. The protein factors that give rise to these complexes show differential DNA binding activities in various buffer solutions at different pH values. The C4-forming protein factor is the interferon (IFN)-alpha/beta-stimulated response factor (ISRF) which shows element B specificity. It preexists in the cytoplasm. ISRF appears to be complexed to an inhibitor (ISRFI) in the cytoplasm and to dissociate from the inhibitor and to translocate into the nucleus upon treatment of cells with IFN-alpha/beta. We propose that IFN-alpha/beta treatment of BALB/c 3T3 can trigger at least two events: 1) loosening of a tight inhibitor-ISRF complex with the release of free ISRF; this may be mediated via phosphorylation of ISRF or ISRFI; 2) translocation of ISRF into the nucleus and binding to the enhancer element B, which results in the activation of 2',5'-oligoadenylate synthetase gene expression.

Distinct positive and negative elements control the limited hepatocyte and choroid plexus expression of transthyretin in transgenic mice

Transthyretin (TTR) is a thyroid hormone transport protein that is secreted by hepatocytes into the serum and by the choroid plexus epithelium into the cerebral spinal fluid. The protein is not made elsewhere in adult animals in significant amounts. We find that the start site for mRNA synthesis is the same in both cell types. The sequences required for mouse TTR expression in cultured hepatocytes include an enhancer at -1.86 to -1.96 kbp and a promoter-proximal region at -70 to -200 bp relative to the mRNA cap site. We demonstrate that in transgenic mice these regulatory regions (approximately 300 bp) are sufficient for quantitatively normal expression of a TTR minigene in hepatocytes, but not for restricted expression in the choroid plexus cells of the brain. Instead, they direct aberrant widespread expression in regions of the brain outside the choroid plexus. With 3 kbp of upstream sequence the TTR minigene is expressed specifically in the choroid plexus as well as in the liver, demonstrating the normal cell type specificity for TTR. These results suggest that 3 kbp of upstream sequence contains positive element(s) required for choroid plexus expression which are distinct from those utilized in the hepatocyte, and may also contain negative element(s) that function to suppress transcription in other brain cell types.