Prognostic significance of human papillomavirus detected with polymerase chain reaction in cervical cancer

In order to investigate the prognostic factors of cervical cancer and its association with human papillomavirus (HPV), we analyzed 50 specimens of cervical cancer with a DNA polymerase chain reaction (PCR) mainly to detect HPV types 16 (HPV 16) and 18 (HPV 18). The result showed that at least 74% (37/50) of the specimens had HPV DNA. Among them, 54% (20/37) of the cases were HPV 16 and 32% (12/37) were HPV 18. These HPV DNA positive patients had poorer differentiation in histology than the HPV DNA negative patients. We draw no conclusion about the prognostic significance of HPV DNA in cervical cancer. Perhaps more cases should be analyzed.

Induction of liver alpha-1 acid glycoprotein gene expression involves both positive and negative transcription factors

Expression of the alpha-1 acid glycoprotein (AGP) gene is liver specific and acute phase responsive. Within the 180-bp region of the AGP promoter, at least five cis elements have been found to interact with trans-acting factors. Four of these elements (A, C, D, and E) interacted with AGP/EBP, a liver-enriched transcription factor, as shown by footprinting analysis and by an anti-AGP/EBP antibody-induced supershift in a gel retardation assay. Modification of these sites by site-directed mutagenesis coupled with transfection analysis indicated that AGP/EBP binding to all of these sites resulted in positive regulation of the promoter. Dose-response data suggest that AGP/EBP binding to these sites results in the cooperative activation of the promoter. In contrast, functional assays showed that element B is a negative regulatory element; this element is recognized by heat-stable DNA-binding factors which are found in many cells and tissues. The regulation of these binding proteins was studied in rat liver treated with lipopolysaccharide (LPS), which induced an acute-phase reaction. We found that LPS treatment resulted in a two- to threefold increase in AGP/EBP activity and a severalfold decrease in the activity of factors that bind to element B in the liver. These results indicate that expression of the AGP gene can be regulated by both positive and negative factors and that the modulation of these factors can account for the LPS induction of the AGP gene.

Nonrandom integration of retroviral DNA in vitro: effect of CpG methylation

We have developed a PCR-based system that allows us to assess the relative frequency of use of specific bases as targets for the avian leukosis virus in vitro integration system. Using this system, we tested the effect of 5-methylation of cytosine in runs of CpG on the distribution of integration target sites. We found that the distribution of preferred integration sites was not uniform along the target DNA; rather, there was a distinct and reproducible pattern of frequently used sites. This pattern was independent of orientation of the integrated DNA, and of overall structure and sequence of the target and fragment amplified. Methylation did not inhibit integration into CpG dinucleotides; on the contrary, this modification created highly preferred targets within runs of alternating CpG. Finally, similar but not identical specificity was observed by using preintegration complexes in infected extracts or purified integrase and DNA as enzyme and substrate. Thus, most of the specificity observed is conferred by interaction of integrase and targets, although it may be modified by other viral and/or cellular components.

Expression cloning and characterization of the canine parietal cell gastrin receptor

Gastrin is an important stimulant of acid secretion by gastric parietal cells and is structurally related to the peptide hormone cholecystokinin (CCK). The pharmacologic properties of the parietal cell gastrin receptor are very similar to the predominant CCK receptor in the brain, CCK-B. Neither the gastrin nor the CCK-B receptor have been cloned thus far, making it difficult to resolve whether these two receptors are distinct. We have isolated a clone encoding the canine gastrin receptor by screening a parietal cell cDNA expression library using a radioligand-binding strategy. Nucleotide sequence analysis revealed an open reading frame encoding a 453-amino acid protein with seven putative hydrophobic transmembrane domains and significant homology with members of the beta-adrenergic family of G protein-coupled receptors. The expressed recombinant receptor shows the same binding specificity for gastrin/CCK agonists and antagonists as the canine parietal cell receptor. Gastrin-stimulated phosphatidylinositol hydrolysis and intracellular Ca2+ mobilization in COS-7 cells expressing the cloned receptor suggest second-messenger signaling through phospholipase C. Affinity labeling of the expressed receptor in COS-7 cells revealed a protein identical in size to the native parietal cell receptor. Gastrin receptor transcripts were identified by high-stringency RNA blot analysis in both parietal cells and cerebral cortex, suggesting that the gastrin and CCK-B receptors are either highly homologous or identical.

Myristate modification does not function as a membrane association signal during poliovirus capsid assembly

The myristate moiety is required for poliovirus assembly. Unlike most other myristoyl-modified proteins, which are membrane associated, no specific membrane association of the poliovirus capsid proteins or assembly intermediates was observed. Furthermore, no apparent differences in membrane association of wild-type and myristoylation deficient mutant viruses could be detected in this analysis. Thus, during poliovirus assembly, the myristate modification is not required as a membrane targeting signal but is more likely involved in structural interactions between protomer subunits.

[Detection of open processus vaginalis by radionuclide scintigraphy]

The processus vaginalis usually obliterates spontaneously from the inguinal ring to the scrotum after the descent of testis has been completed. Under certain conditions, it can be reopened. In present reports, 3 cases with open processus vaginalis were described. The first one is a case of uremia due to chronic glomerulonephritis, suddenly suffering from right scrotal and penile swelling, following continuous ambulatory peritoneal dialysis (CAPD) for 4 months. The second one is a case of uremia, due to unknown etiology, suddenly developing right scrotal and penile swelling after 5 months of CAPD. The third one is a case with uremia of uncertain etiology, suffering from bilateral scrotal and penile swelling in the first month of CAPD, following a wrong procedure, by adding some 200cc more dialysate. Three mCi of Tc-99m phytate or pertechnetate, added into the bag of peritoneal dialysate for each patient, allowed us to visualize a peritoneo-vaginal communication. After surgery one of the patients who had been given followup treatment by radionuclide scintigraphy showed no passage of the labeled infusion in the swollen side of the scrotum. A previous postmortem study of adults dying without clinically apparent inguinal hernia demonstrated an open processus vaginalis in 20% of groins examined. Thus, this study suggests that in placement of catheters for CAPD or ventriculo-peritoneal shunt, Tc-99m pertechnetate/phytate may be given through intraperitoneal injection to detect a subclinical open processus vaginalis.

[Proptosis and optic nerve compression caused by unilateral ethmoidal pyocele: a case report]

This paper presents the case of a 29 year-old male with a left ethmoidal pyocele with orbital and intracranial extensions causing proptosis and a temporal visual field defect of the left eye. The patient had a history of nasal injury as a result of traffic accident eleven years ago, and was well until four months prior to his first visit at which time he had an onset of left eye pain, proptosis, and blurring of vision developed following a URI episode. Since then, fluctuation of symptoms was noted with exacerbation when contracting a common cold. The left ethmoidal pyocele was diagnosed via clinical features and roentgenographic findings. The patient received a Caldwell Luc Operation with endonasal ethmoidectomy and the postoperative condition was good except for constriction of the entire visual field and the depression of temporal internal isopters of the left eye.

Relationship of avian retrovirus DNA synthesis to integration in vitro

An in vitro integration system derived from avian leukosis virus-infected cells supports both intra- and intermolecular integration of the viral DNA. In the absence of polyethylene glycol, intramolecular integration of viral DNA molecules into themselves (autointegration) was preferred. In the presence of polyethylene glycol, integration into an exogenously supplied DNA target was greatly promoted. Analysis of integration intermediates revealed that the strand transfer mechanisms of both reactions were identical to those of retroviruses and some transposons: each 3' end of the donor molecule is joined to a 5' end of the cleaved target DNA. The immediate integration precursor appears to be linear viral DNA with the 3' ends shortened by 2 nucleotides. Finally, in the avian system, most cytoplasmic viral DNA appears to be incomplete and further DNA synthesis is required for integration in vitro.

Primary structure of bovine conglutinin, a member of the C-type animal lectin family

We report the complete amino acid sequence of bovine conglutinin obtained by structural characterization of peptides derived from the protein by various chemical and enzymatic fragmentation methods. The protein consists of 351 amino acid residues including 55 apparent Gly-X-Y repeats with two interruptions. This 171-residue-long collagenous domain separates a short noncollagenous NH2-terminal region of 25 residues from the 155-residue-long globular COOH terminus revealing the structural relation of conglutinin with mannose-binding proteins, pulmonary surfactant-associated proteins, and a complement component C1q. Eight hydroxylysine residues were found in the collagenous domain. All of these hydroxylysine residues which occupy a Y position in a Gly-X-Y triplet are possible glycosylation sites since no phenylthiohydantoin amino acid was identified in automated Edman degradation cycles corresponding to these sites. The noncollagenous COOH domain of conglutinin, on the other hand, contains a carbohydrate recognition domain which shares substantial sequence homology with C-type animal lectins. Conglutinin has the greatest sequence similarity with mannose-binding proteins and pulmonary surfactant-associated proteins.

Efficient autointegration of avian retrovirus DNA in vitro

We have developed a cell-free system for an avian retrovirus that promotes autointegration, one-long-terminal-repeat (LTR) circle formation, and correct integration into exogenous target DNA. In this system, autointegration and one-LTR circle formation occurred far more frequently than integration into exogenous target DNA. Autointegration had the same characteristics of normal integration into target DNA except in its selection of target. Highly efficient autointegration as well as one-LTR circle formation in vitro suggest that there may be a mechanism to prevent these processes in vivo.

Rapid determination by high-performance liquid chromatography of free fatty acids released from rat platelets after derivatization with monodansylcadaverine

The release of free fatty acids from rat platelets, triggered by thrombin stimulation, was monitored by high-performance liquid chromatography (HPLC) after precolumn derivatization with monodansylcadaverine (MDC). A rapid filtration procedure was devised for the precise determination of free fatty acids released from aggregated platelets, instead of the conventional method using a stop solution or enzyme reactions. The fatty acids thus collected were derivatized with MDC in the presence of diethyl phosphorocyanidate (DEPC). The simultaneous separation of MDC derivatives of fatty acids was achieved on a reversed-phase TSKgel ODS-80TM column within 60 min by linear gradient elution, using 0.2 M Tris-HCl buffer (pH 7.8)-methanol (50:50, v/v) and acetonitrile. The MDC derivatives were detected with excitation and emission wavelengths of 340 and 518 nm, respectively. The amounts of liberated fatty acids were in the range from 45.0 pmol for myristoleic acid (C14:1) to 395.0 pmol for palmitic acid (C16:0) per 1.9 x 10(7) platelets.

Biosynthesis of bacterial glycogen. Determination of the amino acid changes that alter the regulatory properties of a mutant Escherichia coli ADP-glucose synthetase

The ADP-glucose synthetase of Escherichia coli K12 mutant 618 has a higher apparent affinity for the activator, fructose 1,6-P2 and a lower apparent affinity for the inhibitor, 5'-AMP, than the normal enzyme. The structural gene, glgC, of the mutant enzyme has been cloned and sequenced (Lee, Y. M., Kumar, A., and Preiss, J. (1987) Nucleic Acids Res. 15, 10603). Substitutions in the mutant enzyme were amino acid residues 296 (Lys to Glu) and 336 (Gly to Asp). Single mutant enzymes, Glu296 and Asp336, were constructed using oligonucleotide-directed mutagenesis. The Glu296 enzyme had the same allosteric kinetic constants as the wild type enzyme. The Asp336 enzyme was catalytically defective. Thus, the mutations at 296 and at 336 separately could not account for the allosteric alterations of the mutant enzyme. A hybrid glgC gene was prepared from genes of wild type and mutant 618 glgC using DNA recombinant techniques. The C-terminal portion of mutant 618 containing Glu296 and Asp336, combined with the N-terminal portion of wild type enzyme, showed allosteric and substrate kinetics similar to mutant 618 enzyme. Thus, alteration of the normal allosteric properties in mutant 618 are due to changes of both Lys296 to Glu and Gly336 to Asp.

Molecular cloning of cDNAs corresponding to two genes of alpha 1-acid glycoprotein and characterization of two alleles of AGP-1 in the mouse

cDNAs corresponding to two types of mouse alpha 1-acid glycoproteins (AGPs), Agp-1 and Agp-2, were cloned and sequenced. Two alleles of Agp-1 were also identified from inbred mice by restriction site polymorphisms. One allele, Agp-1A, is associated with AKR/J, SJL/J, and SWR/J mice, while the other, Agp-1B, is found in BALB/c, DBA/2, C57BL/6, B10, and A/J mice. cDNAs of both Agp-1A and Agp-1B were cloned from BALB/c and (B10 x AKR/J)F1 mice. A single nucleotide substitution in the coding sequence of Agp-1 is responsible for the observed difference in electrophoretic mobilities of Agp-1A and Agp-1B. Several additional nucleotide variations in the 3' untranslated region were also found. In contrast to these two alleles, substantial nucleotide difference exist between Agp-1 and Agp-2. Agp-1 and Agp-2 contain five and six potential N-glycosylation sites, respectively.

A DNA sequencing strategy

A modification of Lin's systematic DNA sequencing strategy is described. A method based on the religation of compatible cohesive ends generated by Sau3AI and BamHI was developed. The original procedure has been simplified and the yield of transfectant has been greatly improved. After complete digestion with BamHI and limited cleavage with Sau3AI, the single-cut linear DNA does not have to be separated from the supercoil or the open circular DNA on an agarose gel. After ligation, the DNA is digested with the restriction enzyme between the cloning site and BamHI site again. The original intact DNA is linearized, whereas the deleted subclone is not. Therefore the background is decreased to an undetectable level. This DNA sequencing strategy was tested on a 1.4-kb cDNA fragment containing the haptoglobin-related sequences. It is not necessary to purify large amounts of RF DNA (500 ng is enough) to get enough subclones. A set of subclones was produced in 1 day and the yield of plaques was about sixfold higher than that published.

Biosynthesis of bacterial glycogen. Use of site-directed mutagenesis to probe the role of tyrosine 114 in the catalytic mechanism of ADP-glucose synthetase from Escherichia coli

Previous covalent modification studies showed that tyrosine 114 of Escherichia coli ADP-glucose synthetase is involved in substrate binding (Lee, Y. M., and Preiss, J. (1986) J. Biol. Chem. 261, 1058-1064). We have prepared, via site-directed mutagenesis, an E. coli ADP-glucose synthetase variant (Phe114) containing a Tyr114 to Phe substitution in order to test whether the phenolic hydroxyl group plays a critical role in catalysis. Kinetic characterization of Phe114 ADP-glucose synthetase indicates that the Tyr114 hydroxyl is not obligatory for the enzyme catalysis. However, the variant enzyme showed altered properties. It showed a decreased apparent affinity for the substrates. The variant enzyme showed less than 2-fold activation by 5 mM fructose 1,6-bisphosphate in the ADP-glucose synthesis direction. In contrast, in the pyrophosphorolysis direction, the mutant enzyme showed about a 30-fold activation by 5 mM fructose 1,6-bisphosphate. The variant enzyme is heat-labile compared to wild type enzyme. It lost about 60% enzyme activity on incubation at 65 degrees C for 5 min in the presence of 30 mM Pi. The wild type enzyme is stable under these conditions. The results indicate that tyrosine 114 is involved directly or indirectly in enzyme catalysis, but is not obligatory for the enzyme catalysis. Conversion of Tyr114 to Phe also alters the regulatory properties of the enzyme with respect to activation by fructose-1,6-P2 and inhibition by AMP.

Covalent modification of the inhibitor-binding site(s) of Escherichia coli ADP-glucose synthetase. Isolation and structural characterization of 8-azido-AMP-incorporated peptides

The photoaffinity inhibitor analog [2-3H]8-azido-AMP is specifically and covalently incorporated into Escherichia coli ADP-glucose synthetase. The reaction site(s) of [2-3H]8-azido-AMP with the enzyme was identified by reverse phase high performance liquid chromatography isolation and chemical characterization of CNBr and mouse submaxillary arginyl protease-generated peptides containing the labeled analog. Three regions of modification, represented by six labeled peptides, accounted for over 85% of the covalently bound label. The major binding region of the azido analog, composed of residues 108-128, contained approximately 55% of the recovered covalently bound radioactivity. A single residue, Tyr-113, contained between 50 and 75% of the label found in the major binding region. This site is the same as the major binding region of the substrate site-specific probe, 8-azido-ADP-[14C]glucose (Lee, Y. M., and Preiss, J. (1986) J. Biol. Chem. 261, 1058-1064). Conformational analysis of this region predicts that it is a part of a Rossmann fold, the supersecondary structure found in many adenine nucleotide-binding proteins. Two minor reaction regions of the enzyme with [2-3H]8-azido-AMP were also identified by chemical characterization. One region, containing 20% of the covalently bound label, was composed of residues 11-68. This region contains Lys-38, the previously determined pyridoxal phosphate-modified allosteric activator site (Parsons, T. F., and Preiss, J. (1978) J. Biol. Chem. 253, 7638-7645). The third minor region of modification, residues 222-254, contained approximately 15% of the covalently bound label. The three modified peptide regions may be juxtaposed in the enzyme's tertiary structure.

Cloning and expression of the Escherichia coli glgC gene from a mutant containing an ADPglucose pyrophosphorylase with altered allosteric properties

A mutant strain of Escherichia coli K-12, designated 618, accumulates glycogen at a faster rate than wild-type strain 356. The mutation affects the ADPglucose pyrophosphorylase regulatory properties (N. Creuzat-Sigal, M. Latil-Damotte, J. Cattaneo, and J. Puig, p. 647-680, in R. Piras and H. G. Pontis, ed., Biochemistry of the Glycocide Linkage, 1972). The enzyme is less dependent on the activator, fructose 1,6 bis-phosphate for activity and is less sensitive to inhibition by the inhibitor, 5'-AMP. The structural gene, glgC, for this allosteric mutant enzyme was cloned into the bacterial plasmid pBR322 by inserting the chromosomal DNA at the PstI site. The glycogen biosynthetic genes were selected by cotransformation of the neighboring asd gene into an E. coli mutant also defective in branching enzyme (glgB) activity. Two recombinant plasmids, pEBL1 and pEBL3, that had PstI chromosomal DNA inserts containing glgC and glgB were isolated. Branching enzyme and ADPglucose pyrophosphorylase activities were increased 240- and 40-fold, respectively, in the asd glgB mutant, E. coli K-12 6281. The E. coli K-12 618 mutant glgC gene product was characterized after transformation of an E. coli B ADPglucose pyrophosphorylase mutant with the recombinant plasmid pEBL3. The kinetic properties of the cloned ADPglucose pyrophosphorylase were similar to those of the E. coli K-12 618 enzyme. The inserted DNA in pEBL1 was arranged in opposite orientation to that in pEBL3.

Covalent modification of Escherichia coli ADPglucose synthetase with 8-azido substrate analogs

Two photoaffinity labeling agents, 8-azido-ATP and 8-azido-ADPglucose, are substrate site specific probes of the Escherichia coli ADPglucose synthetase. In the presence of light (254 nm), the analogs specifically and covalently modify the enzyme with concomitant loss of catalytic activity. The substrate ADPglucose completely protects the enzyme from covalent modification by these 8-azido analogs. ATP, another substrate, also provides nearly 100% protection from 8-azido-ATP inactivation but is less efficient in protection of inactivation by 8-azido-ADPglucose. In the absence of light, however, ADPglucose synthetase can utilize either 8-azido-ATP or 8-azido-ADPglucose as substrates.

Covalent modification of substrate-binding sites of Escherichia coli ADP-glucose synthetase. Isolation and structural characterization of 8-azido-ADP-glucose-incorporated peptides

A photoaffinity substrate analogue, 8-azido-ADP-[14C]glucose, reacts specifically and covalently with Escherichia coli ADP-glucose synthetase. The site(s) of reaction of 8-azido-ADP-[14C]glucose with the enzyme was identified by isolation of tryptic peptides containing the labeled analogue by use of high performance liquid chromatography technique and subsequent NH2-terminal sequence analysis of the purified radioactive peptides. One major binding region of the azido analogue is a peptide segment composed of residues 107-114 of the enzyme's polypeptide chain. Lys 108 and Arg 114 become trypsin-resistant sites when the enzyme is photoinactivated by 8-azido-ADP-[14C] glucose, suggesting that the analogue binds at or near the vicinity of these 2 basic amino acid residues. Conformational analysis of this peptide segment (residues 107-114) shows a strong probability of a reverse beta-turn secondary structure, suggesting that this peptide segment is on the enzyme surface. Two minor reaction regions of the enzyme with the analogue were also identified by chemical characterization. One region was composed of residues 162-207. Lys 194 was previously suggested as the activator-binding site by chemical modification studies with pyridoxal phosphate (Parsons, T. F., and Preiss, J. (1978) J. Biol. Chem. 253, 7638-7645). Another minor region where the analogue binds the tryptic peptide composed of residues 380-385 is near the COOH-terminal side of the enzyme. It is postulated that all these peptide segments are juxtaposed in tertiary structure.

Complete amino acid sequence of copper-zinc superoxide dismutase from Drosophila melanogaster

The complete amino acid sequence of the Drosophila melanogaster Cu,Zn superoxide dismutase subunit has been determined by automated Edman degradation. Sequence analyses were performed on the intact S-carboxymethylated protein, two fragments derived from CNBr cleavage, and three peptides recovered from mouse submaxillary protease digestion of the reduced and S-carboxymethylated enzyme. The peptides were aligned by characterizing peptides yielded by trypsin and Staphylococcus aureus V8 protease. All the peptides studied were purified exclusively by reverse-phase columns of HPLC and were analyzed with an improved liquid-phase sequencer. A molecular weight of 15,750 (subunit) was calculated from the 151 residues sequenced. The amino acid sequence of the Drosophila superoxide dismutase subunit is compared with that of four other eucaryotes: man, horse, cow, and yeast. Comparison of the five primary structures reveals very different rates of evolution at different times. Copper-zinc superoxide dismutase appears to be a very erratic evolutionary clock. Val-Val-Lys-Ala- Val-Cys-Val-Ile-Asn-Gly-Asp-Ala-Lys-Gly-Thr-Val-Phe-Phe-Glu-Gln- Glu-Ser-Ser-Gly-Thr-Pro-Val-Lys-Val-Ser-Gly-Glu-Val-Cys-Gly-Leu- Ala-Lys-Gly-Leu-His-Gly-Phe-His-Val-His-Glu-Phe-Gly-Asp-Asn-Thr- Asn-Gly-Cys-Met-Ser-Ser-Gly-Pro-His-Phe-Asn-Pro-Tyr-Gly-Lys-Glu- His-Gly-Ala-Pro-Val-Asp-Glu-Asn-Arg-His-Leu-Gly-Asp-Leu-Gly-Asn- Ile-Glu-Ala-Thr-Gly-Asp-Cys-Pro-Thr-Lys-Val-Asn-Ile-Thr-Asp-Ser- Lys-Ile-Thr-Leu-Phe-Gly-Ala-Asp-Ser-Ile-Ile-Gly-Arg-Thr-Val-Val-Val- His-Ala-Asp-Ala-Asp-Asp-Leu-Gly-Gln-Gly-Gly-His-Glu-Leu-Ser-Lys- Ser-Thr-Gly-Asn-Ala-Gly-Ala-Arg-Ile-Gly-Cys-Gly-Val-Ile-Gly-Ile- Ala-Lys.