The role of auxin-binding protein 1 in the expansion of tobacco leaf cells.

Tobacco leaf was used to investigate the mechanism of action of auxin-binding protein 1 (ABP1). The distributions of free auxin, ABP1, percentage of leaf nuclei in G2 and the amount of auxin-inducible growth were each determined in control tobacco leaves and leaves over-expressing Arabidopsis ABP1. These parameters were compared with growth of tobacco leaves, measured both spatially and temporally throughout the entire expansion phase. Within a defined window of leaf development, juvenile leaf cells that inducibly expressed Arabidopsis ABP1 prematurely advanced nuclei to the G2 phase. The ABP1-induced increase in cell expansion occured before the advance to the G2 phase, indicating that the ABP1-induced G2 phase advance is an indirect effect of cell expansion. The level of ABP1 was highest at the position of maximum cell expansion, maximum auxin-inducible growth and where the free auxin level was the lowest. In contrast, the position of maximum cell division correlated with higher auxin levels and lower ABP1 levels. Consistent with the correlations observed in leaves, tobacco cells (BY-2) in culture displayed two dose-dependent responses to auxin. At a low auxin concentration, cells expanded, while at a relatively higher concentration, cells divided and incorporated [3H]-thymidine. Antisense suppression of ABP1 in these cells dramatically reduced cell expansion with negligible effect on cell division. Taken together, the data suggest that ABP1 acts at a relatively low level of auxin to mediate cell expansion, whereas high auxin levels stimulate cell division via an unidentified receptor.

Transcription factor Sp3 activates the liver/bone/kidney-type alkaline phosphatase promoter in hematopoietic cells.

The promoter region of the liver/bone/ kidney-type alkaline phosphatase gene was examined to define the cis-acting regulatory sequences and transcription factors responsible for its expression in hematopoietic cells. Transient transfection experiments revealed that regions deleted up to -154 base pairs upstream from the transcription initiation site had significant activities to induce bacterial chloramphenicol acetyltransferase gene. The shortest DNA fragment was found to contain three GC boxes in addition to a TATA box. Electrophoretic mobility shift assay and Southwestern analysis showed that Sp3 could bind to the fragment. Western blot analysis also detected Sp3 protein in eluate from the DNA probe mixed with the nuclear extracts. Through the use of Drosophila Schneider cells that lack the Sp1 family of transcription factors, Sp3 was shown to activate the basal promoter in a dose-dependent manner. When the amount of Sp3 was limited, the most proximal GC box was found to be critical for the basal promoter activity.

Local treatment of AIDS-associated bulky Kaposi's sarcoma in the head and neck region.

Kaposi's sarcoma (KS) is frequently seen in the head and neck regions of HIV-infected patients. We report two cases of patients with AIDS who consulted the ENT clinic. One patient came to our clinic complaining of abnormal sensations in the pharynx, and dysphasia due to a gross KS in the oropharynx. The excision of the tumor improved the difficulty of swallowing. The other patient complained of masticatory problems and tongue pain due to a bulky KS on the dorsal side of the tongue. We treated the tongue lesion with intralesional chemotherapy. The administration of intralesional vinblastine resulted in a partial response. Unless systemic chemotherapy is effective enough to improve a functional disorder, it is thought that local therapy employing excision or intralesional chemotherapy is one of the common therapeutic option of the otolaryngologist, because this treatment avoids severe side effects caused by systemic chemotherapy or radiotherapy.

Characterization of auxin-binding protein 1 from tobacco: content, localization and auxin-binding activity.

There is evidence that auxin-binding protein 1 (ABP1) is an auxin receptor on the plasma membrane. Maize (Zea mays L.) possesses a high level of auxin-binding activity due to ABP1, but no other plant source has been shown to possess such an activity. We have analyzed the ABP1 content of tobacco (Nicotiana tabacum L.) to examine whether or not the ABP1 content of maize is exceptionally high among plants. The ABP1 content of tobacco leaves was shown by quantitative immunoblot analysis to be between 0.7 and 1.2 microg ABP1 per gram of fresh leaf. This value is comparable to the reported value in maize shoots, indicating that ABP1 is present at a similar level in both monocot and dicot plants. The ABP1 content of tobacco leaves was increased up to 20-fold by expression of a recombinant ABP1 gene, and decreased to half of the original value by expression of the antisense gene. Although ABP1 was found mainly in the endoplasmic reticulum fraction, a secreted protein showing a molecular size and epitopes similar to intracellular ABP1 was also detected in the culture medium of tobacco leaf disks. The secretion of this protein was dependent on the expression level of the ABP1 gene.

Cloning and expression of two genes encoding auxin-binding proteins from tobacco.

Two genes encoding the auxin-binding protein (ABP1) of tobacco (Nicotiana tabacum L.), both of which possess the characteristics of a luminal protein of the endoplasmic reticulum (ER), were isolated and sequenced. These genes were composed of at least five exons and four introns. The two coding exons showed 95% sequence homology and coded for two precursor proteins of 187 amino acid residues with molecular masses of 21,256 and 21,453 Da. The deduced amino acid sequences were 93% identical and both possessed an amino-terminal signal peptide, a hydrophilic mature protein region with two potential N-glycosylation sites and a carboxyl-terminal sorting signal, KDEL, for the ER. Restriction mapping of the cDNAs encoding tobacco ABP1, previously purified by amplification of tobacco cDNA libraries by polymerase chain reaction (PCR) using specific primers common to both genes, indicated that both genes were expressed, although one was expressed at a higher level than the other. Genomic Southern blot hybridization showed no other homologous genes except for these two in the tobacco genome. The apparent molecular mass of the mature form of tobacco ABP1 was revealed to be 25 kDa by SDS polyacrylamide gel electrophoresis using affinity-purified anti (tobacco ABP1) antibodies raised against a fusion protein with maltose-binding protein. Expression of the recombinant ABP1 gene in transgenic tobacco resulted in accumulation of the 25 kDa protein. A single point mutation of an amino acid residue at either of the two potential N-glycosylation sites resulted in a decrease in the apparent molecular mass and produced a 22 kDa protein. Mutations at both sites resulted in the formation of a 19.3 kDa protein, suggesting that tobacco ABP1 is glycosylated at two asparagine residues.

Laparoscopic prediction of hepatocellular carcinoma in cirrhosis patients.

Previously, laparoscopic studies have not been successful in predicting the occurrence of small hepatocellular carcinoma because cirrhotic patients had not been separated into groups of those who developed small hepatocellular carcinoma under 3 cm in diameter, and those who did not. Retrospective examination with better separation of the two groups gave improved results. Of the 26 laparoscopic findings, only the presence of large complex regenerative nodules was closely associated with the occurrence of subclinical small hepatocellular carcinoma. The study of other cirrhotic patients with and without large complex regenerative nodules gave a cumulative hepatocellular carcinoma occurrence rate of 73% for patients who had these nodules by the third year after laparoscopy. In contrast, the rate for patients without such nodules was 6%, showing a significant difference (P < 0.05) between the two groups. We concluded that the laparoscopic finding of large complex regenerative nodules of liver cirrhosis can be used to predict the occurrence, or a complication, of subclinical small hepatocellular carcinoma.

Age-related changes in the compound action potentials of the eighth nerve in guinea pigs.

The eighth nerve compound action potential (CAP) in 95 guinea pigs was measured using click stimuli to investigate age-related changes in their neural auditory thresholds. The animals were separated into three groups: group A (n = 43, 86 ears; 2-4 months old); group B (n = 29; 58 ears, 13-15 months old); and group C (n = 23; 46 ears, 23-25 months old). With increasing age, a gradual elevation of CAP thresholds was clearly seen among the three groups. The negative peak (N1) latencies of the CAP were prolonged, and the N1 amplitudes of the CAP decreased. There were significant differences in N1 latencies among the three groups and in N1 amplitudes between groups A and B, and between groups A and C. However, the rate of decline of the thresholds as well as the input-output function curves of the CAP varied in some of the oldest animals, suggesting that there were some individual differences in degenerative aging processes of the auditory system.

A novel intracellular antigen in HL-60 cells that changes in molecular weight after granulocytic and monocytic differentiation.

The present study reports the identification and partial characterization of a novel antigen with M(r) 100,000 by a monoclonal antibody (D29A8) that was obtained by immunizing BALB/c mice with nuclei of HL-60 cells. D29A8 detected mainly a nucleolar macromolecule with M(r) 100,000 (p100). On the other hand, when HL-60 cells were induced to differentiate either into a granulocytic or monocytic pathway, the antibody detected mainly a cytoplasmic macromolecule with M(r) 95,000 (p95). Since two subtypes of the antigen (p100 and p95) appear to be present in the same cells that differ in the stage of cell differentiation, the antigen may play an important role in cellular differentiation.

Relation between markers for viral hepatitis and clinical features of Japanese patients with hepatocellular carcinoma: possible role of alcohol in promoting carcinogenesis.

To assess the relationship between hepatitis virus markers and the clinical features of hepatocellular carcinoma (HCC), we measured markers for hepatitis B virus (HBV) and hepatitis C virus (HCV) in 88 Japanese patients with HCC. Twelve (14%) patients were HBsAg-positive and 67 (76%) were anti-HCV-positive (both c100-3 and c11/c7). HCV-RNA was detected in 8 (38%) of the 21 anti-HCV-negative patients by PCR, so that 75 patients (85%) were infected with HCV. Of the HBsAg-negative patients infected with HCV with no history of blood transfusion, the mean age of the alcoholics (consumption > 80 g ethanol daily for at least 10 years) was lower than that of the non-alcoholics (60 years vs. 65 years, P < 0.05). Among the HBsAg-negative and anti-HCV (or HCV-RNA)-positive patients with a history of blood transfusion, the mean interval between the time of blood transfusion and the diagnosis of HCC in the alcoholics was shorter (21 years) than that in the nonalcoholics (27 years), but the difference was not statistically significant. We conclude that infection by both HCV and HBV may play a role in the development of HCC, and that alcohol consumption may promote carcinogenesis.

Aspartate aminotransferase-linked immunoglobulin complexes in serum of a patient with primary biliary cirrhosis.

A 51-year-old woman who had been treated for primary biliary cirrhosis (PBC) was admitted to our hospital for evaluation of unexplained, isolated, persistently increased aspartate aminotransferase (AST) activity. Results of laboratory tests on admission showed: AST 171 KU, alanine aminotransferase 28 KU, and anti-mitochondrial titer 1/1280. Results of hepatitis B surface antigen (HBs Ag) and hepatitis C virus antibody (HCV Ab; C100-3) assays were negative. Histology of a liver biopsy specimen was compatible with a diagnosis of PBC (stage III of Scheuer's classification). The molecular size of serum AST was estimated to be more than 500,000 by high-performance size-exclusion liquid chromatography. Electrophoretic analysis showed an abnormal band of AST between supernatant AST (sAST) and mitochondrial AST (mAST), which band was characteristic of AST-immunoglobulin complexes (AST-Ig). Ouchterlony double-diffusion and immunoprecipitation tests identified the immunoglobulin component as IgM. The presence of AST-Ig appeared to be responsible for the elevated serum AST.

Structure of the gene for an auxin-binding protein and a gene for 7SL RNA from Arabidopsis thaliana.

A genomic clone encoding an auxin-binding protein (ABP) from the endoplasmic reticulum was isolated from Arabidopsis thaliana. The ABP gene consisted of 5 exons and 4 introns and encoded a polypeptide of 198 residues. A gene encoding the 7SL RNA of the signal recognition particle was located downstream of the ABP gene.

Early and late gene expression in UT-7 cells infected with B19 parvovirus.

UT-7, a human megakaryocytoblastoid cell line, can be persistently infected with B19 parvovirus. We performed detailed serial analysis of parvovirus DNA replication and RNA transcription of synchronized cells. RNA transcription appeared as an early event following infection, with viral RNA detected about 6 hr after infection. In contrast, dimer-replicative intermediate forms of parvovirus DNA did not appear until more than 16 hr after infection. Northern analysis of specific transcripts showed an earlier appearance of nonstructural protein RNA (6 hr) compared to capsid protein RNA (24 hr). The addition of an inhibitor of protein synthesis to block synthesis of nonstructural protein abolished capsid protein RNA transcription as well as DNA replication. Primer extension analysis confirmed the initiation of all transcription from the single P6 promoter. RNA transcription precedes DNA replication of B19 parvovirus in these cells, and RNA processing may have a major role in regulating gene expression.

First continuous propagation of B19 parvovirus in a cell line.

The pathogenic human parvovirus B19 has extreme tropism for human erythroid progenitor cells and has resisted cultivation in conventional cell lines. We report first propagation of this virus in an erythropoietin-dependent strain of a megakaryoblastic leukemia cell line called UT-7. Virus protein was present in about 5% of cells after 1 week of culture. Appropriate ratios of major and minor capsid proteins were determined by immunoblot, and newly synthesized capsid protein was detected by immunoprecipitation of radioactively labeled cell lysates. High molecular weight monomer and dimer intermediates were detected by Southern analysis, indicating active viral replication. Approximately 1,000 genome copies were present per infected cell, and at the optimal multiplicity of infection 20- to 50-fold more virus was produced than inoculated. Virus propagation only occurred in UT-7 cells that were adapted to growth in erythropoietin; virus signal was not detected in UT-7 cells adapted for growth in granulocyte-macrophage colony-stimulating factor or interleukin-3, even with exposure to erythropoietin for several days. Infectious virus was detected in cultures as long as 3 months after inoculation. Despite persistence, there was no evidence of viral integration on Southern analysis. This cell line may prove useful for the production of infectious virus and in the analysis of B19 parvovirus persistence, cytotoxicity, and permissivity.

Recurrent Pneumocystis carinii pneumonia with long interval showing disparate radiographic findings.

A case of recurrent Pneumocystis carinii pneumonia with a long interval between episodes and each episode showing a different radiographic appearance is reported. The radiographic finding in the initial infectious episode was bilateral, patchy, alveolar infiltrate predominantly in the upper and middle lung zones and that in the second infectious episode, six and a half years later, showed bilateral interstitial infiltrate predominantly in the middle and lower lung zones. T cell immunity expressed by mitogen-induced T cell proliferation was clearly different in the two infectious episodes. These differences in radiographic appearance could be due, at least in part, to altered immunological states between the first and second infectious episodes.

Boronate affinity chromatography of gamma-glutamyltransferase in patients with hepatocellular carcinoma.

We analyzed the serum gamma-glutamyltransferase (gamma-GT) by boronate affinity chromatography to ascertain the presence or absence of any changes in the binding properties of gamma-GT toward boronate gels in patients with hepatocellular carcinoma and liver cirrhosis, and in normal controls. The mean gamma-GT activity ratio of the bound (peak 2) and nonbound (peak 1) fraction in patients with hepatocellular carcinoma was significantly higher than that in patients with liver cirrhosis or in normal controls. Thus, the gamma-GT, which has adjacent cis-hydroxyl groups in its carbohydrate moieties, was found to increase in the serum of patients with hepatocellular carcinoma. The positivity rate was examined in patients with hepatocellular carcinoma and liver cirrhosis, using a cut-off level for the peak 2:peak 1 ratio of 1.05 (mean + 2 SD of liver cirrhosis). Nineteen (42.2%) patients with hepatocellular carcinoma had a ratio of peak 2:peak 1 higher than 1.05. Nine of the 19 patients who had serum alpha-fetoprotein levels below 100 ng/ml had an elevated peak 2:peak 1 ratio. In total, 77.8% of the occurrence of hepatocellular carcinoma could be detected by a combination of these two markers. Three patients who had developed hepatocellular carcinoma during the course of cirrhosis but remained negative for alpha-fetoprotein throughout the course developed higher levels of peak 2:peak 1 ratio when hepatocellular carcinoma occurred. These results indicate that the two markers, the peak 2:peak 1 ratio of serum gamma-GT activity and serum alpha-fetoprotein level, may be considered to serve as complementary markers for the diagnosis of hepatocellular carcinoma.

Two genes, atpC1 and atpC2, for the gamma subunit of Arabidopsis thaliana chloroplast ATP synthase.

Arabidopsis thaliana has two genes (atpC1, atpC2) coding for gamma subunits of chloroplast ATP synthase. The atpC1 and atpC2 were cloned and sequenced. They had no introns within the reading frames and coded for proteins of 373 and 386 amino acid residues, respectively, including putative transit sequences (50 and 60 amino acid residues, respectively). In contrast, the spinach gamma subunit gene had two introns within the reading frame. The mature sequences coded by the two genes of A. thaliana (atpC1, 323 residues; atpC2, 326 residues) were homologous with that of spinach (J. Miki, M. Maeda, Y. Mukohata, and M. Futai (1988) FEBS Lett. 232, 221-226): the homologies of gamma subunits coded by atpC1 and atpC2 were 72%, those of the subunits coded by atpC1 and spinach cDNA were 84%, and those of the proteins coded by atpC2 and spinach cDNA were 71%. Like the spinach subunit, the gamma subunits coded by the two genes had unique regulatory domains not found in mitochondrial or bacterial subunits. Poly(A)+ mRNAs corresponding to atpC1 (1.5 kilobases) and atpC2 (2.5 kilobases) were detected in illuminated plants, the amount of the former being at least 140 times that of the latter. The atpC1 mRNA was not found in dark-adapted plants. Nuclear protein(s) specifically bound to the upstream region of atpC1 was detected by gel shift assay and its binding was shown to be inhibited by the GT-1 element of the gene encoding the ribulose-1,5-bisphosphate carboxylase small subunit, which is expressed under illumination (P. J. Green, S. A. Kay, and N. H. Chau (1987) EMBO J. 6, 2543-2549). Consistent with these findings, an increased amount of the gamma subunit was detected immunochemically in illuminated plants.

Serum pseudouridine as a biochemical marker in patients with hepatocellular carcinoma.

The concentration of serum pseudouridine, a degradation product of transfer ribonucleic acid, was determined by high-performance liquid chromatography in patients with hepatocellular carcinoma, liver cirrhosis, other benign hepatobiliary diseases, and healthy controls. The serum pseudouridine concentration in patients with hepatocellular carcinoma was significantly higher than that in patients with cirrhosis or the controls. Twenty-seven (51.9%) of 52 patients with hepatocellular carcinoma had serum pseudouridine concentrations higher than the mean value for healthy controls plus 2 SD. Fourteen of the 36 patients who had serum alpha-fetoprotein levels below 400 ng/ml, had elevated serum pseudouridine concentration. In total, 36 of the 52 patients (69.2%) could be detected by combination of these two markers. Two patients who had developed hepatocellular carcinoma during the course of cirrhosis and were continuously negative for alpha-fetoprotein, had higher levels of the pseudouridine concentration when hepatocellular carcinoma occurred. Furthermore, 4 of the 7 patients who had a very small cancer and were negative for alpha-fetoprotein, had elevated serum pseudouridine concentration. These results indicate that serum pseudouridine is a useful biochemical marker and that serum pseudouridine and alpha-fetoprotein in combination are considered to serve as complementary markers, for the diagnosis of hepatocellular carcinoma.

Escherichia coli H+-ATPase. Glutamic acid 185 in beta subunit is essential for its structure and assembly.

The uncD gene for the beta subunit of Escherichia coli H+-ATPase was cloned downstream of the lac promoter and mutagenized (Glu-185----Gln or Lys) by an oligonucleotide-directed procedure. The recombinant plasmid was introduced into a strain in which the unc operon for subunits of H+-ATPase was deleted. The wild-type or mutant beta subunit synthesized amounted to about 10% total cell protein and was mainly found in the cytoplasmic fraction. These subunits could be purified to almost homogeneity by conventional procedures. The wild-type and two mutant beta subunits had essentially the same Kd values for 8-anilinonaphthalene-1-sulfonate, aurovertin, and ATP, although the fluorescence intensities of 8-anilinonaphthalene-1-sulfonate and aurovertin were significantly less when bound to the two mutant beta subunits than when bound to the wild-type subunit. The three beta subunits showed essentially the same circular dichroism spectra, indicating alpha-helical contents of about 16-18%. Thus, the mutations did not cause marked change of the secondary structure of the subunit. However, measurements of theta 208 during linear increase in temperature suggested that replacement of Glu-185 by Gln or Lys slightly changed the stability of the secondary structure. Only trace amounts of alpha beta gamma complexes could be reconstituted using the two mutant beta subunits. These results suggest that Glu-185 or the region in its vicinity may be essential for subunit assembly. The methods developed in this study should be useful for further studies on the beta subunit.