Restoration of P-glycoprotein function is involved in the increase of natural killer activity with exogenous interleukin-15 in human immunodeficiency virus-infected individuals

A depressed level of natural killer (NK) activity is one of the various immunologic abnormalities in human immunodeficiency virus (HIV) infection. Interleukin-15 (IL-15), an immunotherapeutic candidate in HIV infection, increases NK activity and induces the excretion of CC-chemokines from divergent immune cells, but the mechanisms of NK activity enhancement by IL-15 stimulation is not clearly established in HIV infection. This study examined whether CC-chemokines, which are known to increase NK activity, are secreted adequately in HIV-infected individuals, and also investigated whether P-glycoprotein is involved in NK activity enhancement after IL-15 administration. NK activity increased with IL-15 stimulation in NK cells of HIV-infected individuals, as it does in normal NK cells. IL-15 stimulates NK cells to secrete CC-chemokines, such as, macrophage inflammatory protein-1alpha (MIP-1alpha), macrophage chemotactic protein-1alpha (MCP-1alpha) and regulated upon activation, normal T cells expressed and secreted (RANTES) in both HIV-infected individuals and controls with no significant difference. P-glycoprotein expression and function is decreased in HIV-infected individuals and restored only in NK cells of HIV-infected individuals after IL-15 stimulation. P-glycoprotein may play a role in the mechanism of increased NK cell activity in HIV-infected individuals after IL-15 stimulation.

Muscle abnormalities in juvenile dermatomyositis patients: P-31 magnetic resonance spectroscopy studies

OBJECTIVE

To characterize metabolic abnormalities in the muscles of children with the juvenile variant of dermatomyositis (JDM) by the use of noninvasive P-31 magnetic resonance spectroscopy (MRS).

METHODS

Thirteen patients with JDM (ages 4-16 years) were studied. Biochemical status was evaluated with P-31 MRS by determining the concentrations of the high-energy phosphate compounds, ATP and phosphocreatine (PCr), ratios of inorganic phosphate (Pi) to PCr (Pi:PCr ratio), levels of free cytosolic ADP, and phosphorylation potentials (PPs) during rest, exercise, and recovery.

RESULTS

Significant metabolic abnormalities were observed in the thigh muscles of 10 severely affected patients during rest, 2 graded levels of exercise, and recovery. Mean ATP and PCr levels in the muscles of JDM patients were 35-40% below the normal control values (P < 0.003). These data, along with elevated Pi:PCr ratios, higher ADP levels, and abnormal values for PPs, indicated defective oxidative phosphorylation in the mitochondria of diseased JDM muscles. MRS findings were normal in 2 additional patients who had improved with prednisone treatment and in 1 patient who had no muscle weakness (amyopathic variant of JDM).

CONCLUSION

JDM patients can be monitored with noninvasive P-31 MRS without sedation. Biochemical defects in energy metabolism are concordant with the weakness and fatigue reported by JDM patients. Quantitative MRS data are useful for evaluating patients and optimizing drug treatment regimens.

Genomic organization and tissue-specific expression of rat urocortin

The genomic organization of rat urocortin was determined using both cDNA and liver genomic DNA as templates for polymerase chain reactions. A single intron of 261 bp was found upstream to the ATG start codon, and the whole urocortin coding sequence was shown to be contained in a single exon. Relying on these results, oligonucleotide primers were designed, which can differentiate genomic DNA contamination from cDNA-derived signals in a reverse transcription-polymerase chain reaction. Tissue screening for urocortin expression revealed that the mid-brain is the major site of urocortin mRNA expression, and that other peripheral organs, including lymphoid tissues and peripheral blood lymphocytes, do not produce urocortin.

Dissolution of xylose metabolism in Lactococcus lactis

Xylose metabolism, a variable phenotype in strains of Lactococcus lactis, was studied and evidence was obtained for the accumulation of mutations that inactivate the xyl operon. The xylose metabolism operon (xylRAB) was sequenced from three strains of lactococci. Fragments of 4.2, 4.2, and 5.4 kb that included the xyl locus were sequenced from L. lactis subsp. lactis B-4449 (formerly Lactobacillus xylosus), L. lactis subsp. lactis IO-1, and L. lactis subsp. lactis 210, respectively. The two environmental isolates, L. lactis B-4449 and L. lactis IO-1, produce active xylose isomerases and xylulokinases and can metabolize xylose. L. lactis 210, a dairy starter culture strain, has neither xylose isomerase nor xylulokinase activity and is Xyl(-). Xylose isomerase and xylulokinase activities are induced by xylose and repressed by glucose in the two Xyl(+) strains. Sequence comparisons revealed a number of point mutations in the xylA, xylB, and xylR genes in L. lactis 210, IO-1, and B-4449. None of these mutations, with the exception of a premature stop codon in xylB, are obviously lethal, since they lie outside of regions recognized as critical for activity. Nevertheless, either cumulatively or because of indirect affects on the structures of catalytic sites, these mutations render some strains of L. lactis unable to metabolize xylose.

Reduced-frequency concurrent and terminal feedback: a test of the guidance hypothesis

In 2 experiments, the authors manipulated the frequency of concurrent feedback to discern the effects on learning. In each experiment, participants (N = 48, Experiment 1; N = 36, Experiment 2) attempted to reproduce a criterion force-production waveform (5 s in duration) presented on the computer monitor. Consistent with the guidance hypothesis, the results of Experiment 1 indicated very strong guiding effects of concurrent feedback and strong dependence on the feedback, as indicated by participants' extremely poor performance upon feedback withdrawal in retention. As predicted by the guidance hypothesis, dependence on the feedback was reduced as a result of reducing the frequency of the concurrent feedback. The results of Experiment 2 indicated that one can enhance learning by providing concurrent and terminal feedback on 1 trial, with no feedback on the subsequent trial. In that way, the strong guiding effects of concurrent feedback could be realized and the beneficial effects of terminal feedback could also be achieved.

Protein kinase A activity is required for depolarization-induced proline-rich tyrosine kinase 2 and mitogen-activated protein kinase activation in PC12 cells

Protein kinase A (PKA) plays an essential role in the depolarization-induced c-fos expression in PC12 cells although the exact mechanism is unknown. Here we demonstrate that PKA is required for depolarization-induced activation of both extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinase in PC12 cells. In addition, we have found that the depolarization-induced tyrosine phosphorylation of proline-rich tyrosine kinase (PYK) 2, a key calcium-sensitive upstream mediator of MAP kinase activation, is profoundly blocked by PKA inhibition. In contrast to the depolarization-induced signaling, the ERK and PYK2 activation by bradykinin (1 microM), a G-protein coupled receptor agonist, was not blocked by PKA inhibition. These findings suggest that PKA inhibition prevents depolarization-induced PYK2/MAP kinase pathway activation, thereby inhibiting the early gene expression.

p16 is a major inactivation target in hepatocellular carcinoma

BACKGROUND

The p16(INK4A) gene encodes 2 cell cycle regulator proteins, p16 and p14(ARF), by alternative splicing. This genetic locus also contains another cell cycle regulator gene, p15(INK4B), which encodes p15. The inactivation of the p16 protein has been demonstrated in some hepatocellular carcinomas (HCCs); however, the inactivation of the other 2 cell regulator proteins and their inactivation patterns are not well characterized.

METHODS

To characterize the role of the above 3 cell cycle regulator proteins in HCCs, the authors examined the genomic status of the p16(INK4A) and p15(INK4B) genes and their RNA products in 20 HCC tissues and 7 human HCC cell lines. Homozygous deletions in each exon of p16(INK4A) and p15(INK4B) were evaluated by comparative multiplex polymerase chain reaction (PCR), and the methylation status of the p16(INK4A) and p15(INK4B) promoter region was analyzed by methylation specific PCR.

RESULTS

Homozygous deletions were found in 6 of 20 HCCs (30%) and 2 of 7 HCC cell lines (29%). In 20 HCCs, the frequency of homozygous deletions was 20% in exon 1 of p15(INK4B), 20% in exon 2 of p15(INK4B), 10% in exon 1beta of p16(INK4A), 25% in exon 1alpha of p16(INK4A), 15% in exon 2 of p16(INK4A), and 15% in exon 3 of p16(INK4A). The authors found hypermethylation of the p16(INK4A) promoter region in 7 HCCs (35%) and 3 HCC cell lines (43%). The overall frequency of p16 alterations in HCCs, including hypermethylation and homozygous deletions, was 60% (12 of 20 cases). According to reverse transcriptase-PCR analysis, the absence of RNA expression was most frequent in p16 (11 of 20 cases, 55%) and less frequent in p15 (7 of 20 cases, 35%) and p14(ARF) (5 of 20 cases, 25%).

CONCLUSIONS

Among the 3 cell cycle regulator proteins encoded at the 9p21 genetic locus, inactivation of p16 is the most frequent event in HCCs in which promoter hypermethylation and homozygous deletions are the common mechanisms.

Apoptosis in rabbit haemorrhagic disease

Rabbit haemorrhagic disease virus (RHDV) causes an acute hepatitis and disseminated intravascular coagulation. Six rabbits were inoculated experimentally with RHDV to investigate any potential relationship between infection and apoptosis in the liver. Two rabbits were killed at 12 h post-inoculation (PI) and two at 24 h PI. The remaining two rabbits died at 30 h and 31 h PI. Immunohistochemical labelling for RHDV antigen-positive cells, TUNEL assay for apoptotic cells, and DNA analysis were performed on samples of liver. The four rabbits that died or were killed 24-31 h PI had acute hepatitis with infiltration of heterophils and necrotic hepatocytes. RHDV antigen-positive cells and apoptotic cells appeared in the centriacinar areas at 12 h PI; subsequently they spread to periacinar areas and increased in number, but the viral antigen-positive cells outnumbered apoptotic cells. At 24-31 h PI, few apoptotic cells were recognized in the areas infiltrated with lymphocytes and heterophils. The results suggested an association between RHDV infection and apoptosis of hepatocytes.

Brain uptake and the analgesic effect of oxytocin--its usefulness as an analgesic agent

To establish the usefulness of oxytocin (OT) as an analgesic for women in delivery, the pharmacokinetic parameters and blood-brain barrier (BBB) permeability of [3H]OT were obtained using an intravenous injection technique or the internal carotid artery perfusion/capillary depletion (ICAP/CDM) method. Brain uptake of OT was similar to that of sucrose, plasma space marker, indicating that OT has a poor BBB permeability. Moreover, the analgesic effects of OT injected through the jugular vein on nociception were evaluated by the tail-flick method. The antinociceptive effects of OT injected at a dose of 0.2 mg/kg or 2 mg/kg were dose-dependent. In addition, the analgesic effects of OT on the CNS were unaffected by naloxone, a m-receptor antagonist. In a similar manner to the opioid system, OT may play a modulatory role in antinociception.

Activation of heat shock factor 1 by hyperosmotic or hypo-osmotic stress is drastically attenuated in normal human fibroblasts during senescence

We have previously reported that osmotic stress prominently induces the DNA binding activity of the heat shock transcription factor 1 (HSF1). In the present study, we examined the effects of medium osmolarity on both the activation of HSF1 and the programmed cell death in normal human fibroblasts during cellular senescence. The activation of HSF1 occurred rapidly in presenescent (early passage) IMR-90 cells when exposed to either hypo-osmotic or hyperosmotic stress. In contrast, the activation of HSF1 was significantly attenuated in senescent cells. Western blot analysis indicated that equal amounts of HSF1 were present as monomers in the cytoplasm of both presenescent and senescent cells in normal growth medium. Under either hypo-osmotic or hyperosmotic stress, trimerization and nuclear localization of HSF1 occurred in presenescent cells but not in senescent cells. More than 80% of HSF1 in senescent cells remained as monomers in the cytoplasm under osmotic stress, suggesting a defect in the signal transduction pathways that lead to HSF1 trimerization or a dysfunction in the HSF1 protein itself. Possible involvement of mitogen-activated protein kinase (MAPK) signal transduction pathways in the activation HSF1 was investigated by monitoring the activation of the three MAPKs, ERK1/2, JNK1/2, and p38, in cells exposed to hypo-osmotic or hyperosmotic stress. All three MAPKs were activated by hyperosmotic stress but not hypo-osmotic stress, suggesting that the MAPK signal transduction pathways may not be directly linked to the osmotic stress-induced activation of HSF1. In contrast to the rapid heat shock transcription factor (HSF) activation, apoptosis occurred only after long-term exposure to hypo-osmotic or hyperosmotic stress. Despite the prominent induction of HSF1 activation, the presenescent cells were more sensitive than the senescent cells to the osmotic stress-induced apoptosis.

Dual anticancer activity of 8-Cl-cAMP: inhibition of cell proliferation and induction of apoptotic cell death

8-Cl-cAMP induces apoptotic cell death in human cancer cells. To look at this more closely, we examined the changes in the levels of Bcl-2 family proteins during 8-Cl-cAMP-induced apoptosis of SH-SY5Y human neuroblastoma cells. Following the treatment with 8-Cl-cAMP, Bcl-2 was transiently down-regulated and Bad was increased continuously up to day 5. In addition, overexpression of Bcl-2 efficiently blocked the 8-Cl-cAMP-induced apoptosis, suggesting Bcl-2 family proteins may be involved in the 8-Cl-cAMP-induced apoptosis. The contribution of the apoptotic cell death and the inhibition of cell proliferation in the 8-Cl-cAMP-induced growth inhibition was closely monitored in the Bcl-2-overexpressing cells. Though the apoptosis was reduced significantly, no significant difference was observed in the inhibition of cell proliferation up to day 2 of 8-Cl-cAMP treatment. These results suggest that 8-Cl-cAMP exerts anticancer activity by two distinct mechanisms, i.e. , through the inhibition of cell proliferation as well as the induction of apoptosis. Supporting this notion was the observations that (1) suppression of apoptosis by zVAD did not abrogate 8-Cl-cAMP-induced inhibition of cell proliferation, and (2) 8-Cl-cAMP did not show additive inhibition of cell proliferation in RIIbeta-overexpressing cells.

Frequent alteration of p63 expression in human primary bladder carcinomas

p63, a recently identified member of the p53 gene family, encodes multiple products with transactivating, death-inducing, and dominant-negative activities. To explore the penetrance of p63 in bladder carcinogenesis, we performed expression and mutation analyses of two major isotypes, TAp63 and deltaNp63, in 63 bladder specimens. In 12 normal tissues, TAp63 was expressed at an easily detectable level whereas deltaNp63 was absent or extremely low. While none of 47 carcinomas showed allelic deletion of the gene, marked reduction of TAp63 and abnormal overexpression of deltaNp63 were found in 25 (53.2%) and 30 (63.8%) carcinomas, respectively. Tumor-specific alteration of TAp63 and deltaNp63 expression was identified in two and three of six matched sets, respectively. In addition, reduced expression of TAp63 showed a correlation with tumor stage and grade. Abnormal expression of TAp63 or deltaNp63 isoform was also observed in three of four cell lines, and treatment with 5-Aza-2'-deoxycytidine led to up- or down-regulation of TAp63 and/or deltaNp63 expression, suggesting that the promoters of both isoforms might be affected by DNA methylation, but not in a reciprocal fashion. No sequence alteration of p63 was identified in 47 carcinomas whereas 17 (34.8%) of these showed p53 mutations, and no association between p63 expression and the mutational status of p53 or expression of p21Waf1, MDM2, and 14-3-3sigma was recognized. Our data suggest that altered expression of p63 is a frequent event in bladder carcinogenesis and might contribute to the progression of bladder tumors, possibly via the mechanism(s) distinct from the p53 pathway.

p16 is a major inactivation target in hepatocellular carcinoma

BACKGROUND

The p16(INK4A) gene encodes 2 cell cycle regulator proteins, p16 and p14(ARF), by alternative splicing. This genetic locus also contains another cell cycle regulator gene, p15(INK4B), which encodes p15. The inactivation of the p16 protein has been demonstrated in some hepatocellular carcinomas (HCCs); however, the inactivation of the other 2 cell regulator proteins and their inactivation patterns are not well characterized.

METHODS

To characterize the role of the above 3 cell cycle regulator proteins in HCCs, the authors examined the genomic status of the p16(INK4A) and p15(INK4B) genes and their RNA products in 20 HCC tissues and 7 human HCC cell lines. Homozygous deletions in each exon of p16(INK4A) and p15(INK4B) were evaluated by comparative multiplex polymerase chain reaction (PCR), and the methylation status of the p16(INK4A) and p15(INK4B) promoter region was analyzed by methylation specific PCR.

RESULTS

Homozygous deletions were found in 6 of 20 HCCs (30%) and 2 of 7 HCC cell lines (29%). In 20 HCCs, the frequency of homozygous deletions was 20% in exon 1 of p15(INK4B), 20% in exon 2 of p15(INK4B), 10% in exon 1beta of p16(INK4A), 25% in exon 1alpha of p16(INK4A), 15% in exon 2 of p16(INK4A), and 15% in exon 3 of p16(INK4A). The authors found hypermethylation of the p16(INK4A) promoter region in 7 HCCs (35%) and 3 HCC cell lines (43%). The overall frequency of p16 alterations in HCCs, including hypermethylation and homozygous deletions, was 60% (12 of 20 cases). According to reverse transcriptase-PCR analysis, the absence of RNA expression was most frequent in p16 (11 of 20 cases, 55%) and less frequent in p15 (7 of 20 cases, 35%) and p14(ARF) (5 of 20 cases, 25%).

CONCLUSIONS

Among the 3 cell cycle regulator proteins encoded at the 9p21 genetic locus, inactivation of p16 is the most frequent event in HCCs in which promoter hypermethylation and homozygous deletions are the common mechanisms.

Diagnostic accuracy in sinus fungus balls: CT scan and operative findings

A fungus ball may be characterized by its radiologic and operative gross findings. Computed tomography (CT) revealed a rim of soft tissue attenuation of variable thickening along the bony walls of the isolated paranasal sinus, or mottled hyperdense foci of variable size. A small amount of friable muddy mass surrounded by purulent secretions or dirty brown clay-like materials provide highly pathognomonic findings. However, these characteristics may induce clinical misdiagnosis. During the last four years we experienced 11 cases of chronic paranasal sinusitis in which pathologic examination failed to confirm fungal hyphae, despite clinical suspicion of a fungus ball based on operative or CT findings. During the same period, we also experienced another 52 patients who were diagnosed with fungus ball at pathologic examination. To evaluate the diagnostic accuracy of CT scans and operative gross findings in sinus fungus balls, we reviewed the medical records of these 63 patients and also reviewed CT scans and operative records of another 1127 patients who received endoscopic sinus surgery for chronic rhinosinusitis. The sensitivity of CT evaluation was 62%, and specificity was 99%. The false-positive and false-negative rate were 22% and 2%, respectively. With regard to operative findings, such as clay-like inspissated mucus, the sensitivity, specificity, and predictive value positive rate were 100%, 99%, and 83%, respectively. To make a diagnosis of fungus ball, a high index of suspicion is necessary and a pathologic confirmation is mandatory.

Association of tightly spiraled bacterial infection and gastritis in pigs

Tightly spiral bacteria were observed only in the pyloric mucosa of 4 (8.0%) of 50 swine stomachs, mainly in the surface of epithelia, the gastric pits and the lumen of gastric glands. The presence of the spiral bacteria was significantly associated with chronic pyloric gastritis (p<0.05). Mean gastritis score of the bacteria-positive pyloric mucosa was 3.25 +/- 0.25, whereas that of the bacteria-negative pyloric mucosa was 2.37 +/- 0.12. Parakeratosis and hyperkeratosis were spontaneously seen in the mucosa layer of pars oesophagea, regardless of the bacterial infection. Marked infiltration of mononuclear cells and granulocytes were seen in the cardiac mucosa, regardless of the bacterial infection. Mean gastritis score of the bacteria-positive cardiac mucosa was 3.27 +/- 0.32, whereas that of the bacteria-negative cardiac mucosa was 2.84 +/- 0.13. There was no significant difference between the bacteria-positive and negative cardiac mucosa (p>0.05). Inflammatory response in the fundic mucosa was rare (gastritis score=0.75 +/- 0.08). The tightly spiraled bactera were not cultured with various culture media. These results suggest that the presence of tightly spiraled bacteria is associated with only the pyloric gastritis in pigs.

Production of D-amino acid using whole cells of recombinant Escherichia coli with separately and coexpressed D-hydantoinase and N-carbamoylase

We developed a fully enzymatic process employing D-hydantoinase and N-carbamoylase for the production of D-amino acid from 5'-monosubstituted hydantoin. For the comparison of the reaction systems using two sequential enzymes, D-hydantoinase of Bacillus stearothermophilus SD1 and N-carbamoyl-D-amino acid amidohydrolase (N-carbamoylase) of Agrobacterium tumefaciens NRRL B11291 were separately expressed in each host cell and coexpressed in the same host cell. A high level and constitutive expression of both enzymes in Escherichia coli in a soluble form was achieved using a promoter derived from B. stearothermophilus SD1. The expression levels of both enzymes ranged from 17% to 23% of the total soluble protein, depending on the expression system. In the case of employing separately expressed enzymes, the product yield of D-hydroxyphenylglycine from D,L-p-hydroxyphenylhydantoin and productivity were 71% and 2.57 mM/g-cell/h in 15 h, respectively. The accumulation of N-carbamoyl-D-hydroxyphenylglycine was significant over the reaction time. On the other hand, use of coexpressed enzymes resulted in 98% product yield of D-hydroxyphenylglycine in 15 h, minimizing the level of intermediates in the reaction mixture. The productivity of coexpressed whole cell reaction was estimated to be 6.47 mM/g-cell/h in 15 h. The coexpressed system was tested for an elevated concentration of D,L-p-hydroxyphenylhydantoin, and efficient production can be achieved.

Bioadhesive-based dosage forms: the next generation

Prolonged contact time of a drug with a body tissue, through the use of a bioadhesive polymer, can significantly improve the performance of many drugs. These improvements range from better treatment of local pathologies to improved drug bioavailability and controlled release to enhanced patient compliance. There are abundant examples in the literature over the past 15 years of these improvements using first generation or "off-the-shelf" bioadhesive polymers. The present mini-review will remind us of the success achieved with these first-generation polymers and focus on proposals for the next-generation polymers and attendant benefits likely to occur with these improved polymeric systems.

Functional characterization of the rat gamma-glutamyl transpeptidase promoter that is expressed in transformed rat liver epithelial cells

In the rat the gamma-glutamyl transpeptidase (GGT) gene codes for at least four different messenger RNAs (mRNA I to mRNA IV) which differ only in their 5' untranslated regions and are transcribed from a single copy gene in a tissue-specific manner. In the liver GGT expression is up-regulated in transformed cells. To understand the induction mechanisms of GGT activity by transformation, we previously cloned the 5' region of the rat GGT gene which contains the 5' untranslated leader sequence for mRNA I. In the present study, using transfection and reporter gene assays, I have demonstrated that (1) the sequence from positions -369 to +226 drives a relatively strong promoter activity in C5 and AKG cell lines, transformed rat liver epithelial cells, but a very weak one in RLE-228 cells, a normal rat liver epithelial cell line; and (2) removal of the region between -418 and -369 increases CAT activity more than 10-fold in RLE-228, C5 and AKG cells, and the DNA fragment spanning nucleotides -761 to -292 significantly reduces CAT activity driven by the adenine phosphoribosyl transferase (APRT) promoter in RLE-228 cells.

Dimerization of the insulin-like growth factor II/mannose 6-phosphate receptor

The insulin-like growth factor II/mannose 6-phosphate receptor (IGF2R) interacts with lysosomal enzymes through two binding domains in its extracytoplasmic domain. We report in the accompanying article (Byrd, J. C., and MacDonald, R. G. (2000) J. Biol. Chem. 275, 18638-18646) that only one of the two extracytoplasmic mannose 6-phosphate (Man-6-P) binding domains is necessary for high affinity Man-6-P ligand binding, suggesting that, like the cation-dependent Man-6-P receptor, oligomerization of the IGF2R contributes to high affinity interaction with lysosomal enzymes. In the present study, we have directly characterized both naturally occurring and engineered forms of the IGF2R for their ability to form oligomeric structures. Whereas gel filtration chromatography suggested that purified bovine IGF2R species exist in a monomeric form, native gel electrophoresis allowed for the separation of dimeric and monomeric forms of the receptors with distinct phosphomannosyl ligand binding characteristics. The ability of the IGF2R to form oligomeric complexes was confirmed and localized to the extracytoplasmic domain through the use of epitope-tagged soluble IGF2R constructs bearing deletions of the transmembrane and cytoplasmic domains. Finally, chimeric receptors were engineered containing the extracytoplasmic and transmembrane domains of the IGF2R fused to the cytoplasmic domain of the epidermal growth factor receptor with which dimerization of the chimeras could be monitored by measuring autophosphorylation. Collectively, these results show that the IGF2R is capable of forming oligomeric complexes, most likely dimers, in the absence of Man-6-P ligands.

Involvement of two NF-kappa B binding elements in tumor necrosis factor alpha -, CD40-, and epstein-barr virus latent membrane protein 1-mediated induction of the cellular inhibitor of apoptosis protein 2 gene

The antiapoptotic function of NF-kappaB is believed to be mediated through the induction of antiapoptotic genes. Among the antiapoptotic genes, cellular inhibitor of apoptosis protein 2 (c-IAP2/HIAP-1/MIHC) is originally identified as a molecule recruited to the tumor necrosis factor (TNF) receptor complex, and its expression is preferentially up-regulated by TNF and other stimuli activating NF-kappaB. However, direct evidence of transcriptional regulation of NF-kappaB on the c-IAP2 gene is still missing. Here, we have cloned and characterized the promoter region required for NF-kappaB-dependent transcription of the c-IAP2 gene. Sequencing of a 3.5-kilobase fragment of the 5'-flanking region of the c-IAP2 gene has identified a TATA-like sequence and potential binding sites for nuclear factor of activated T cells, interferon regulatory factor 1, activator protein 1, glucocorticoid response element, and three putative NF-kappaB binding elements. Deletion and mutational analysis of the 5'-flanking region linked to the luciferase gene revealed that transcriptional activation by TNF or interleukin 1 is mediated cooperatively by two NF-kappaB binding sites. Electrophoretic mobility shift assays characterized that the two NF-kappaB sites can be recognized and bound by the NF-kappaB p50/p65 heterodimer. In addition, the transcription of c-IAP2 promoter was strongly up-regulated when CD40 or Epstein-Barr virus latent membrane protein 1 was overexpressed.

Cloning and characterization of the murine pkd2 promoter

Pkd2, the mouse homologue of PKD2, the gene responsible for the second form of autosomal dominant polycystic kidney disease, is highly expressed in fetal and adult mouse tissues. The expression of Pkd2 is developmentally regulated. To begin to dissect out the regulatory mechanism of Pkd2 expression, we characterized the basic features of the gene structure and identified potential cis-regulatory elements of Pkd2 transcription. Pkd2 spans 42 kb with a transcription start site 165 bp upstream of the translation start codon. Exon 1 of Pkd2 is 755 bp long, and the full-length transcript is 5215 bp. The Pkd2 promoter region is GC-rich and lacks a consensus TATA or CCAAT box. Consensus binding sites for the transcription factors Sp-1, NF-1, and Ap-2 lie in the 5' upstream region of Pkd2. The Sp-1 binding site is conserved in 5' upstream sequences of both the mouse and the human genes. The CAT activity of a series of upstream segments from +178 to -2749 was assessed in MDCK, LLCPK1, COS-7, and HEK293 cells. Deletion analysis identified a 409-bp fragment from position -221 to +178 responsible for basal promoter activity. A 922-bp fragment from -744 to +178 showed the highest level of CAT activity in the cell lines tested. These data define a functional promoter candidate region for Pkd2.

Detection of human herpesvirus 6 variant A in peripheral blood mononuclear cells from multiple sclerosis patients

Several authors report that human herpesvirus 6 (HHV-6) variants have different epidemiologies, in vivo tropism and pathogenic potentials. However, it is not well known what pathogenic roles its neurotropism might have in the variant type. As some active plaques of multiple sclerosis (MS) brain tissue harbor HHV-6 DNA divergent from the prototype virus, the possibility that the variant strain may play a role in the pathogenesis of MS has been suggested. Therefore, we tried to investigate the role of HHV-6 variants in the pathogenesis of MS. As HHV-6 is predominantly a T-cell-tropic virus, we examined HHV-6 DNA sequences in peripheral blood mononuclear cells (PBMC) from 34 MS patients, 6 with idiopathic transverse myelitis, 2 with optic neuritis and 20 healthy controls. Nested polymerase chain reaction was used to detect the HHV-6 genome. To discern HHV-6 variants A and B, amplification products were digested by restriction enzyme. We found that 7 of 34 MS patients and 2 of 6 patients with idiopathic transverse myelitis had the HHV-6 genome. On the contrary, there was no HHV-6 genome in the control group. All genomic sequences were of HHV-6 variant A (HHV-6A). Our results suggest that the detection of HHV-6A in the PBMC of patients with MS may raise the possibility of a relationship between latent HHV-6A infection and the pathogenesis of MS.

Disruption of synaptic transmission or clock-gene-product oscillations in circadian pacemaker cells of Drosophila cause abnormal behavioral rhythms

To study the function of clock-gene-expressing neurons, the tetanus-toxin light chain (TeTxLC), which blocks chemical synaptic transmission, was expressed under the control of promoters of the clock genes period (per) and timeless (tim), each fused to GAL4-encoding sequences. Although TeTxLC did not affect cycling of a clock-gene product at the gross level, it disrupted the rhythmic behavior of adult Drosophila. In constant darkness, the proportion of rhythmic flies was reduced in flies expressing active TeTxLC compared to controls, including those expressing inactive toxin. The behavior of TeTxLC-expressing flies was less synchronized to light:dark cycles than that of controls. To determine which neurons are responsible for these effects on behavior, the toxin was also expressed in restricted subsets of per/tim-expressing, laterally located pacemaker neurons by expressing TeTxLC under the control of a driver in which GAL4-encoding sequences are fused to the promoter of the pigment dispersing factor (pdf) gene. pdf-gal4-driven TeTxLC expression had relatively little effect on behavioral rhythms, implying that per/tim neurons other than pdf-expressing lateral neurons participate in the generation of rhythmic behavior. In another set of experiments, period gene products were expressed under the control of per-gal4 or tim-gal4. This resulted in an increased level of PER protein in many brain cells and reduction of bioluminescence cycling reported by a per-luciferase transgene, especially in the case of per expression affected by tim-gal4. This indicates a disruption of the transcriptional feedback loop that is a part of the oscillatory mechanism underlying Drosophila's circadian rhythms. Consistent with this molecular defect, the proportion of rhythmic individuals in constant darkness was subnormal in flies expressing PER under the control of tim-gal4, and their behavior in light:dark cycles was abnormal.