Homologous plasminogen N-terminal and plasminogen-related gene A and B peptides. Characterization of cDNAs and recombinant fusion proteins

The cDNA corresponding to exons 2-4 of the processed human plasminogen (Pgn) gene, encoding the N-terminal peptide domain (NTP), has been cloned, expressed in Escherichia coli as a recombinant protein (r-NTP) containing a hexahistidine tag, and refolded to the native structure that contains two internal cystine bridges. RNA expression of the two Pgn-related genes, PRG A and PRG B, that potentially encode 9-kDa polypeptides having extensive similarity to the NTP has been investigated. Using RNA-based PCR with liver RNA as template, we demonstrate that PRG A encodes a detectable mRNA species. PRG A and PRG B have been found to be transcribed in the liver and yield virtually identical mRNAs. Neither of the PRGs are expressed in a variety of other normal tissues, as determined by Northern blot analysis. Factor-Xa digestion of the tagged r-NTP yields cleavage products which indicates that the expressed r-NTP domain of Pgn is endowed with a flexible conformation. Recombinant PRG B protein (r-PRG B) fused to a hexahistidine tag was purified and analyzed for structural integrity. Preliminary 1H-NMR spectroscopic data for r-NTP and r-PRG B indicate relatively fast amide 1H-2H exchange in 2H2O and close conformational characteristics for the two homologous polypeptides. Far ultraviolet-CD spectra for r-NTP and r-PRG B at pH 7.0 indicate similar defined secondary structure content for both domains, with 13-17% alpha-helix and 24-27% antiparallel beta-sheet. The fact that two transcriptionally active genes encode almost identical polypeptides supports the hypothesis that the Pgn NTP, together with the putative polypeptides encoded by the PRGs, may serve an important function, such as controlling the conformation of Pgn and thus its susceptibility to tissue activators.

Expression, isolation and characterization of a mutated human plasminogen kringle 3 with a functional lysine binding site

Each kringle of human plasminogen (HPg) except kringle 3 (K3) exhibits affinity for omega-aminocarboxylic acids. Assuming that the K3 domain contains a preformed but nonfunctional lysine binding site (LBS), Lys311 was altered by site-directed mutagenesis into Asp311 in accordance with the consensus sequence of the LBS. Cys297 involved in the interkringle disulfide bridge was mutated into Ser297 to minimize dimerization and aggregation. The mutated K3 TYQ[K3HPg/C297S/K311D]DS (r-K3mut) was expressed in Escherichia coli, isolated on an Ni2(+)-nitrilotriacetic acid-agarose column, refolded and purified on a lysine Bio-Gel column. Fluorescence titration indicates affinity of r-K3mut for omega-aminocarboxylic acids with the following association constants (Kass, mM-1): 5-aminopentanoic acid: 1.3; 6-aminohexanoic acid: 4.2; 7-aminoheptanoic acid: 0.5; trans-(aminomethyl)cyclohexanecarboxylic acid: 12.7; p-benzylaminesulfonic acid: 11.8. r-K3mut exhibits an affinity similar to native and mutated (R220G, E221D) K2. The results indicate the presence of a preformed but nonfunctional LBS in native K3 of HPg. We were able to demonstrate for the first time that an appropriate mutation in the LBS of a kringle produced a weak but distinct affinity for omega-aminocarboxylic acids.

Localisation of enzymes in live spermatozoa by CellProbe reagents (preliminary results)

As a new approach, various synthetic fluorogenic substrates, the CellProbe reagents, were applied to examine the topography of their cleavage in vital human spermatozoa. These substrates are able to enter the cells without requiring previous cell permeabilization and can produce a fluorescent dye after cleavage, depending on enzyme activity. Vital spermatozoa from samples with normal spermiogram parameters showed fluorescence in different areas and intensity after incubation with a variety of substrates for aminopeptidase A, peroxides, subtilisin, dipeptidylpeptidase IV (DPP IV), cathepsin D, glucosidase and glucuronidase, but not with the substrate for galactosidase. Fluorescence was mainly located in the acrosomal cap (substrates for DPP IV, subtilisin, cathepsin D, glucosidase and glucuronidase) in the middle piece and head (substrates for peroxides, glucosidase), in the sperm head (substrates for aminopeptidase A) and occasionally in the tail (substrate for glucosidase). The substrate for subtilisin may play a role in andrology, because subtilisin is a serine protease like acrosin. This substrate may possibly be used to determine the acrosin activity in vital spermatozoa. The CellProbe reagents for fluorescence cytoenzymology may serve advanced methods in both clinical andrology and spermiological research, presuming that the characteristics and qualities of the synthetic substrates are correct. Therefore, more extended studies will be necessary to determine their clinical utility and significance under physiological and pathological conditions.

Characterization of kringle domains of angiostatin as antagonists of endothelial cell migration, an important process in angiogenesis

Angiogenesis is a complex process that involves endothelial cell proliferation, migration, basement membrane degradation, and neovessel organization. Angiostatin, consisting of four homologous triple-disulfide bridged kringle domains, has previously been shown to exhibit profound inhibition of endothelial cell proliferation in vitro and angiogenesis in vivo. It was also demonstrated that angiostatin could suppress the growth of a variety of tumors via the blocking of angiogenesis. The primary aim of our study was to characterize the kringle domains of angiostatin for their inhibitory activities of endothelial cell migration in order to elucidate their contributions to the anti-angiogenic function of angiostatin. In this report, we demonstrate for the first time that the kringles of angiostatin play different roles in inhibiting endothelial cell migration, a crucial process in angiogenesis. Kringle 4, which has only marginal anti-proliferative activity, is among the most potent fragments in inhibiting endothelial cell migration (IC50 of approximately 500 nM). In contrast, kringle 1-3, which is equivalent to angiostatin in inhibiting endothelial cell proliferation, manifests only a modest anti-migratory effect. The combination of kringle 1-3 and kringle 4 results in an anti-migratory activity comparable to that of angiostatin. When kringle 1 is removed from kringle 1-3, the resulting kringle 2-3 becomes more potent than kringle 1-3. This implies that kringle 1, although virtually ineffective in inhibiting endothelial cell migration, may influence the conformation of kringle 1-3 to alter its anti-migratory activity. We also show that disruption of the kringle structure by reducing/alkylating agents markedly attenuates the anti-migratory activity of angiostatin, demonstrating the significance of kringle conformation in maintaining the anti-angiogenic activity of angiostatin. Our data suggest that different kringle domains may contribute to the overall anti-angiogenic function of angiostatin by their distinct anti-migratory activities.

Kringle 2 mediates high affinity binding of plasminogen to an internal sequence in streptococcal surface protein PAM

Many cells express receptors for plasminogen (Pg), although the responsible molecules in most cases are poorly defined. In contrast, the group A streptococcal surface protein PAM contains a domain with two 13-amino acid residue long repeated sequences (a1 and a2) responsible for Pg binding. Here we identify the region in Pg that interacts with PAM. A radiolabeled proteolytic plasminogen fragment containing the first three kringles (K1-K3) interacted with streptococci expressing PAM or a chimeric surface protein harboring the a1a2 sequence. In contrast, plasminogen fragments containing kringle 4 or kringle 5 and the activable serine proteinase domain failed to bind to PAM-expressing group A streptococci. A synthetic and a recombinant polypeptide containing the a1a2 sequence both bound to immobilized recombinant K2 (rK2) but not to rK1 or rK3. The interaction between the a repeat region and rK2 was reversible, and rK2 completely blocked the binding of Pg to the a1a2 region. The binding of the a repeat containing polypeptide to K2 occurred with an equilibrium association constant of 4.5 x 10(7) M-1, as determined by surface plasmon resonance, a value close to that (1.6 x 10(7) M-1) calculated for the a1a2-Pg interaction. Inhibition experiments suggested involvement of the lysine-binding site of K2 in the interaction. These data demonstrate that K2 contains the major Pg-binding site for PAM, providing the first well defined example of an interaction between an internal Pg-binding region in a protein and a single kringle domain.

Structural/functional properties of the Glu1-HSer57 N-terminal fragment of human plasminogen: conformational characterization and interaction with kringle domains

The Glu1-Val79 N-terminal peptide (NTP) domain of human plasminogen (Pgn) is followed by a tandem array of five kringle (K) structures of approximately 9 kDa each. K1, K2, K4, and K5 contain each a lysine-binding site (LBS). Pgn was cleaved with CNBr and the Glul-HSer57 N-terminal fragment (CB-NTP) isolated. In addition, the Ile27-Ile56 peptide (L-NTP) that spans the doubly S-S bridged loop segment of NTP was synthesized. Pgn kringles were generated either by proteolytic fragmentation of Pgn (K4, K5) or via recombinant gene expression (rK1, rK2, and rK3). Interactions of CB-NTP with each of the Pgn kringles were monitored by 1H-NMR at 500 MHz and values for the equilibrium association constants (Ka) determined: rK1, Ka approximately 4.6 mM(-1); rK2, Ka approximately 3.3 mM(-1); K4, Ka approximately 6.2 mM-'; K5, K, 2.3 mM(-1). Thus, the lysine-binding kringles interact with CB-NTP more strongly than with Nalpha-acetyl-L-lysine methyl ester (Ka < 0.6 mM(-l), which reveals specificity for the NTP. In contrast, CB-NTP does not measurably interact with rK3. which is devoid of a LBS. CB-NTP and L-NTP 1H-NMR spectra were assigned and interproton distances estimated from 1H-1H Overhauser (NOESY) experiments. Structures of L-NTP and the Glul-Ile27 segment of CB-NTP were computed via restrained dynamic simulated annealing/energy minimization (SA/EM) protocols. Conformational models of CB-NTP were generated by joining the two (sub)structures followed by a round of constrained SA/EM. Helical turns are indicated for segments 6-9, 12-16, 28-30, and 45-48. Within the Cys34-Cys42 loop of L-NTP, the structure of the Glu-Glu-Asp-Glu-Glu39 segment appears to be relatively less defined, as is the case for the stretch containing Lys5O within the Cys42-Cys54 segment, consistent with the latter possibly interacting with kringle domains in intact Glul-Pgn. Overall, the CB-NTP and L-NTP fragments are of low regular secondary structure content-as indicated by UV-CD spectra- and exhibit fast amide 1H-2H exchange in 2H2O, suggestive of high flexibility.

Lysine-50 is a likely site for anchoring the plasminogen N-terminal peptide to lysine-binding kringles

Interactions between the kringle 4 (K4) domain of human plasminogen (Pgn) and segments of the N-terminal Glu1-Lys77 peptide (NTP) have been investigated via 1H-NMR at 500 MHz. NTP peptide stretches devoid of Lys residues but carrying an internal Arg residue show negligible affinity toward K4 (equilibrium association constant Ka < 0.05 mM(-1)). In contrast, while most fragments containing an internal Lys residue exhibit affinities comparable to that shown by the blocked Lys derivative Nalpha-acetyl-L-lysine-methyl ester (Ka approximately 0.2 mM(-1), peptides encompassing Lys50O consistently show higher Ka values. Among the investigated linear peptides, Nalpha-acetyl-Ala-Phe-Tyr-His-Ser-Ser-Lys5O-Glu-Gln-NH2 (AcAFYHSK5OEQ-NH2) exhibits the strongest interaction with K4 (Ka approximately 1.4 mM(-1)), followed by AcYHSK50EQ-NH2 (Ka approximately 0.9 mM(-1)). Relative to the wild-type sequence, mutated hexapeptides exhibit lesser affinity for K4. When a Lys50 --> Ser mutation was introduced (==> AcYHSS50EQ-NH2), binding was abolished. The Ile27-lle56 construct (L-NTP) contains the Lys50 site within a loop constrained by two cystine bridges. The propensity of recombinant Pgn K1 (rK1) and K2 (rK2) modules, and of Pgn fragments encompassing the intact K4 and K5 domains, for binding L-NTP, was investigated. We find that L-NTP interacts with rK1, rK2, K4, and K5-all lysine-binding kringles-in a fashion that closely mimics what has been observed for the Glul-HSer57 N-terminal fragment of Pgn (CB-NTP). Thus, both the constellation of kringle lysine binding site (LBS) aromatic residues that are perturbed upon complexation of L-NTP and magnitudes of kringle-L-NTP binding affinities (rK1, Ka approximately 4.3 mM(-1); rK2, Ka approximately 3.7 mM(-1; K4, Ka approximately 6.4 mM(1); and K5, Ka approximately 2.1 mM(-1)) are essentially the same as for the corresponding kringle-CB-NTP pairs. Molecular modeling studies suggest that the Glu39-Lys50 stretch in NTP generates an area that complements, both topologically and electrostatically, the solvent-exposed kringle LBS surface.

Adhesion molecules and matrix proteins on human spermatozoa

Ejaculated spermatozoa and spermatogenic cells express alpha- and beta-chains of beta 1, 3 and 4 integrins as well as their ligands fibronectin and laminin in an extended intra- and interindividual variation and in different patterns of location. The mRNA transcripts of these molecules were detectable by nested polymerase chain reaction in the spermatozoa. The conclusion of a functional competence of these adhesion molecules (AM) was supported by their relation to the results of the zona-free hamster oocyte penetration (HOP) test, the in vitro fertilization of human oocytes and cell attachment assays. AM labelling was influenced by the disintegration of the sperm plasma membrane, especially in seminal plasma, by progesterone, human follicular fluid and microorganisms, but was barely modified by sperm cryopreservation. Despite substantial advances in the knowledge about sperm adhesion molecules, many questions remain to be answered.

Eosinophil granule proteins expressed in ocular cicatricial pemphigoid

BACKGROUND

Blister formation and tissue damage in bullous pemphigoid have been attributed to the release of eosinophil granule proteins--namely, to eosinophil derived cationic protein (ECP) and major basic protein (MBP). In the present investigation these eosinophil granule proteins were studied in the conjunctiva of patients with ocular cicatricial pemphigoid (OCP).

METHODS

Conjunctival biopsy specimens obtained from patients with subacute (n = 8) or chronic conjunctival disease (n = 13) were analysed histologically and immunohistochemically using antibodies directed against EG1 (stored and secreted ECP), EG2 (secreted ECP), MBP, CD45 (common leucocyte antigen), CD3 (pan T cell marker), and HLA-DR (class II antigen).

RESULTS

Subepithelial mononuclear cells, mast cells, and neutrophils were detected in all specimens. The number of mononuclear cells, neutrophils, CD45+ cells, CD3+ cells, and the HLA-DR expression were significantly higher in the subacute than in the chronic disease group. Some eosinophils were found in specimens from five of eight patients with subacute OCP, but in none of the patients with chronic disease. The eosinophil granule proteins (ECP and MBP) were found in the epithelium and substantia propria in patients with subacute conjunctivitis.

CONCLUSIONS

Subepithelial cell infiltration in the conjunctiva greatly differs between subacute and chronic ocular cicatricial pemphigoid specimens. The findings suggest that eosinophil granule proteins may participate in tissue damage in acute phase of inflammation in OCP.

Cutaneous reactions at sites of herpes zoster scars: an expanded spectrum

Several types of cutaneous lesions have previously been described at the sites of herpes zoster scars. We describe 16 patients with cutaneous lesions which had developed on herpes zoster scars. Biopsies were taken from these lesions, and a polymerase chain reaction assay was used to detect the viral genome in paraffin-embedded specimens. Histopathological findings enabled diagnosis of nonspecific granulomatous dermatitis in five patients, granulomatous vasculitis in two patients, lichen sclerosus in two patients, and pseudolymphoma, keloid, sarcoidal granuloma, granuloma annulare, granulomatous folliculitis, lichen planus and cutaneous Rosai-Dorfman disease, each in one patient. Varicella-zoster virus DNA was not identified in any of the patients. Granulomatous folliculitis, lichen sclerosus and cutaneous Rosai-Dorfman disease have not previously been described in herpes zoster scars, but they are three new cutaneous reaction patterns that may have developed within these scars. Our investigations indicate that the cutaneous reactions appearing in herpes zoster scars are not due to the persistence of varicella-zoster virus DNA within the lesions.

Chicken antibodies to a recombinant fragment of the equine immunoglobulin epsilon heavy-chain recognising native horse IgE

An equine immunoglobulin E (IgE) heavy-chain cDNA fragment (CH3-CH4, nucleotides 1132 to 1592) was cloned, expressed in Escherichia coli as a fusion protein with a [His]6-tag and purified over a Ni-NTA column. The recombinant protein was used to immunise hens. Testing of the raised egg yolk immunoglobulin G (IgG) in Western-blot and ELISA revealed high titres against the recombinant equine IgE fragment (reqIgEf). The reqIgEf-specific IgG was successfully affinity-purified on an unconventional affinity matrix: the [His]6-tagged recombinant IgE fragment was bound to Ni-NTA agarose and used to adsorb specific immunoglobulins. In Western-blot of ammonium sulphate precipitated horse serum and bronchoalveolar lavage fluid, separated by SDS-PAGE under denaturing-reducing conditions, the raised antibodies reacted with a protein of approximately 80 kDa. A reaction of the reqIgEf-specific IgG was seen with a 190-200 kDa band when the same horse serum or bronchoalveolar fluid (BALF) was separated under non-reducing conditions. These reactions could be inhibited by preincubation of the immune IgG with reqIgEf, while preincubation with horse IgG did not inhibit the reaction. Antibody-affinity chromatography of horse serum with the reqIgEf-specific chicken IgG resulted in an enrichment of the 80 kDa protein in denaturing Western-blot. Determination of the amino acid composition of this protein and comparison with the equine IgE heavy- chain sequence strongly indicates that the 80 kDa band corresponds to the heavy chain of the horse IgE. The reqIgEf-specific chicken IgG was further characterised in an ELISA for the detection of allergen-specific horse IgE. It was demonstrated that heating IgE positive horse sera at 54 degrees C for 10 min drastically diminished the recognition by the reqIgEf-specific chicken IgG. The reaction is inhibitable by preincubation with reqIgEf in a concentration dependent manner. In addition, preincubation with horse IgG, a nonrelevant [His]6-tagged protein or 2% equine colostrum had no influence on the reqIgEf-specific chicken IgG binding characteristic. This antibody recognising horse IgE will be useful for further studies on the pathogenesis of equine allergic diseases.

Ligand preferences of kringle 2 and homologous domains of human plasminogen: canvassing weak, intermediate, and high-affinity binding sites by 1H-NMR

The interaction of various small aliphatic and aromatic ionic ligands with the human plasminogen (HPg) recombinant kringle 2 (r-K2) domain has been investigated by 1H-NMR spectroscopy at 500 MHz. The results are compared against ligand-binding properties of the homologous, lysine-binding HPg kringle 1 (K1), kringle 4 (K4), and kringle 5 (K5). The investigated ligands include the omega-aminocarboxylic acids 4-aminobutyric acid (4-ABA), 5-aminopentanoic acid (5-APA), 6-aminohexanoic acid (6-AHA), 7-aminoheptanoic acid (7-AHA), lysine and arginine derivatives with free and blocked alpha-amino and/or carboxylate groups, and a number of cyclic analogs, zwitterions of similar size such as trans-(aminomethyl)cyclohexanecarboxylic acid (AMCHA) and p-benzylaminesulfonic acid (BASA), and the nonzwitterions benzylamine and benzamidine. Equilibrium association constant (Ka) values were determined from 1H-NMR ligand titration profiles. Among the aliphatic linear ligands, 5-APA (Ka approximately 3.4 mM-1) shows the strongest interaction with r-K2 followed by 6-AHA (Ka approximately 2.3 mM-1), 7-AHA (Ka approximately 0.45 mM-1), and 4-ABA (Ka approximately 0.22 mM-1). In contrast, r-K1, K4, and K5 exhibit a preference for 6-AHA (Ka approximately 74.2, 21.0, and 10.6 mM-1, respectively), a ligand approximately 1.14 A longer than 5-APA. Mutations R220G and E221D increase the affinity of r-K2 for these ligands but leave the selectivity profile essentially unaffected: 5-APA > 6-AHA > 7-AHA > 4-ABA (Ka approximately 6.5, 3.9, 1.8, and 0.74 mM-1, respectively). We find that, while r-K2 definitely interacts with Nalpha-acetyl-L-lysine and L-lysine (Ka approximately 0.96 and 0.68 mM-1, respectively), the affinity for analogs carrying a blocked carboxylate group is relatively weak (Ka approximately 0.1 mM-1). We also investigated the interaction of r-K2 with L-arginine (Ka approximately 0.31 mM-1) and its derivatives Nalpha-acetyl-L-arginine (Ka approximately 0.55 mM-1), Nalpha-acetyl-L-arginine methyl ester (Ka approximately 0.07 mM-1), and L-arginine methyl ester (Ka approximately 0.03 mM-1). Zwitterionic gamma-guanidinobutyric acid, containing one less methylene group than arginine, exhibits a Ka of approximately 0.28 mM-1. The affinity of r-K2 for lysine and arginine derivatives suggests that K2 could play a role in intermolecular as well as intramolecular interactions of HPg. As is the case for the HPg K1, K4, and K5, among the tested ligands, AMCHA is the one which interacts most firmly with r-K2 (Ka approximately 7.3 mM-1) while the aromatic ligands BASA, benzylamine, and benzamidine exhibit Ka values of approximately 4.0, approximately 0.04, and approximately 0.03 mM-1, respectively. The relative stability of these interactions indicates a strict requirement for both cationic and anionic polar groups in the ligand, whereas the presence of a lipophilic aromatic group seems to be of lesser consequence. Ligand-induced shifts of r-K2 (1)H-NMR signals and two-dimensional nuclear Overhauser effect (NOESY) experiments in the presence of 6-AHA reveal direct involvement of residues Tyr36, Trp62, Phe64, and Trp72 (kringle residue numbering convention) in ligand binding. Starting from the X-ray crystallographic structure of HPg K4 and the intermolecular 1H-NMR NOE data, two models of the K2 lysine binding site complexed to 6-AHA have been derived which differ mainly in the extent of electrostatic pairing between the K2 Arg56 and Glu57 side chains. Competition between these two conformations in equilibrium may account for the relatively lesser affinity of the K2 domain for zwitterionic lysine-type ligands.

Elucidation of the disulfide-bonding pattern in the factor I modules of the sixth component (C6) of human complement

Complement component C6 is known to contain two factor I modules in tandem at its C-terminus. To localize the disulfide bridges in those domains, native C6 was cleaved with trypsin, followed by subtilisin. The resulting digests were separated by reversed-phase HPLC, and all of the potential cystine-containing fragments were detected by a fluorescence assay and amino acid composition analyses. Final identification of the disulfide bonds was achieved by Edman degradation of the corresponding peptides. From the data gained a 1-3, 2-9, 4-7, 5-10, 6-8 pattern was determined (Cys752-Cys802, Cys763-Cys780, Cys765-Cys816, Cys772-Cys795, Cys841-Cys852, Cys846-Cys898, Cys859-Cys876, Cys861-Cys911, Cys867-Cys891). These findings are compared with the strongly related complement components C7 and factor I.

Localization of adhesion molecules on human spermatozoa by fluorescence microscopy

The expression of adhesion molecules on human spermatozoa of healthy probands was analysed. The localization patterns of adhesion molecules (AM) on the spermatozoal surface were documented by fluorescence microscopy. Spermatozoa were incubated with antibodies against alpha 1 (CD49a), alpha 2 (CD49b), alpha 3 (CD49c), alpha 4 (CD49d), alpha 5 (CD49e), alpha 6 (CD49f) chains of beta 1 integrins, beta 1 (CD29), beta 2 (CD18), alpha V (CD51), beta 3 (CD61) and beta 4 integrin chains, the LFA-3 (Lymphocyte function antigen, CD58) from the immunoglobulin superfamily and the extra-cellular matrix proteins laminin, fibronectin and collagen IV. For collagen IV, alpha 1 and alpha 2 chains no expression could be noticed. Laminin was detected at the acrosomal membrane, fibronectin and beta 4 chain mainly at the equatorial membrane. The fibronectin receptors alpha 3, alpha 4 and alpha 5 chains of the beta 1 integrins were mainly located on acrosomal and equatorial membrane areas. Laminin receptor alpha 6 chain was located postacrosomal and less frequently acrosomal. beta 2 chain and vitronectin receptors alpha V and beta 3 chains had a mainly postacrosomal localization pattern. LFA-3 was found constantly on postacrosomal membrane areas. Double staining technique was used to prove the simultaneous occurrence of fibronectin and its integrin receptors alpha 3, alpha 4 and alpha 5 chains and of alpha V and beta 2 chains on spermatozoa. The localization patterns of integrins on double stained spermatozoa were similar to the patterns described for single stained spermatozoa. The localization of fibronectin appeared to be influenced by the presence of integrins: the typical equatorial fibronectin band disappeared in case of an equatorial localization of integrins.

Detection of HPV DNA in trichilemmomas by polymerase chain reaction

Paraffin sections of 11 formalin-fixed trichilemmomas were investigated for the presence of human papillomavirus (HPV) DNA by the polymerase chain reaction (PCR) with the degenerated consensus primer pairs. PCRs were conducted with different annealing temperatures. When the annealing temperature was reduced from 55 degrees C to 50 degrees C, amplification products of the expected size were obtained for all 11 cases investigated. Determination of the HPV type was performed by cloning and sequencing of the amplification products. The sequence analysis of the eleven cloned amplicons gave the following data: based on sequence comparison with published amino acid sequences, the best homology was found to epidermodysplasia verruciformis (EV)-associated HPVs (supergroup B). In four specimens an HPV type 23 related type was found; five specimens contained HPV sequences which did not match with one of the known HPV types, but had the closest homology to HPV types 15, 17, and 37. Three of the HPV variants which had not been characterised, displayed identical sequences. Two additional HPV amplification fragments displayed played 100% homology to HPV-6b. These results demonstrate, for the first time, the presence of HPV DNA in trichilemmomas. The sequence data suggest that HPV variants or types in trichilemmoma are members of the EV-associated HPV supergroup B.

Kringle domains of human angiostatin. Characterization of the anti-proliferative activity on endothelial cells

Recently we have identified angiostatin, an endogenous angiogenesis inhibitor of 38 kDa which specifically blocks the growth of endothelial cells (O'Reilly, M. S., Holmgren, L., Shing, Y., Chen, C. , Rosenthal, R. A., Moses, M., Lane, W. S., Cao, Y., Sage, E. H., and Folkman, J. (1994) Cell 79, 315-328; Folkman, J. (1995) Nat. Med. 1, 27-31). Angiostatin was shown to represent an internal fragment of plasminogen containing the first four kringle structures. We now report on the inhibitory effects of individual or combined kringle structures of angiostatin on capillary endothelial cell proliferation. Recombinant kringle 1 and kringle 3 exhibit potent inhibitory activity with half-maximal concentrations (ED50) of 320 nM and 460 nM, respectively. Also, recombinant kringle 2 displays a significant inhibition, although decreased compared with both kringle 1 and kringle 3. In contrast, kringle 4 is an ineffective inhibitor of basic fibroblast growth factor-stimulated endothelial cell proliferation. Among the tandem kringle arrays, the recombinant kringle 2-3 fragment exerts inhibitory activity similar to kringle 2 alone. However, relative to kringle 2-3, a marked enhancement in inhibition is observed when individual kringle 2 and kringle 3 are added together to endothelial cells. This implies that it is necessary to open the cystine bridge between kringle 2 and kringle 3 to obtain the maximal inhibitory effect of kringle 2-3. An increased (<2-fold) inhibitory activity is observed for the kringle 1-3 fragment (ED50 = 70 nM) compared with kringle 1-4 (ED50 = 135 nM). These data indicate that the anti-proliferative activity of angiostatin on endothelial cells is shared by kringle 1, kringle 2, and kringle 3, but probably not by kringle 4 and that more potent inhibition results when kringle 4 is removed from angiostatin. Thus, in view of the variable lysine affinity of the homologous domains, it would appear that lysine binding capability does not correlate with the relative inhibitory effects of the kringle-containing constructs. However, as we also demonstrate, appropriate folding of kringle structures is essential for angiostatin to maintain its full anti-endothelial activity.

[Cutaneous malacoplakia in a patient with psoriasis vulgaris]

A 58 year old patient suffering from psoriasis vulgaris had typical erythematous, scaly plaques for 20 years. In addition, an erosive, therapy-resistant plaque was found in the perianal region. A biopsy was taken to exclude malignancy; it showed intracytoplasmic Michaelis-Gutmann-bodies as a marker for malakoplakia, which rarely occurs in the skin. In further electron microscopic investigation, intracytoplasmatic bacteria could be demonstrated. An underlying malignancy or chronic renal insufficiency with immunosuppression were not found in this patient; both are often associated with malakoplakia.

Detection of mRNA transcripts of beta 1 integrins in ejaculated human spermatozoa by nested reverse transcription-polymerase chain reaction

Matrix proteins (e.g. fibronectin, laminin and vitronectin) and their receptors, especially beta 1 integrins, may play a role in sperm-oocyte interactions. These proteins are well described on spermatogenic cells but especially in ejaculated spermatozoa, the presence of mRNA as a necessity for their synthesis is not clear. Therefore the mRNA synthesis of the beta 1, alpha 3, alpha 4, alpha 5 and alpha 6 chains (fibronectin and laminin receptors) of the beta 1 integrins was investigated by nested reverse transcription-polymerase chain reaction (RT-PCR) in spermatozoa of human semen samples (n = 18) which showed normal classical semen parameters after swim-up preparation. After the second amplification, we obtained specific signals for mRNA transcripts of the beta 1, alpha 3, alpha 4 and alpha 6 chains in 17 of 18 semen samples investigated. All control PCRs were negative for somatic cell transcripts and contamination by somatic cells was excluded. These results demonstrate for the first time that human ejaculated spermatozoa contain the mRNA transcripts of beta 1 integrins and support the role of these proteins in adhesive mechanisms in the fertilization process.

[HPV-5 typing with nested PCR and sequencing in epidermodysplasia verruciformis]

We report a case of epidermodysplasia verruciformis (EV) with typical cutaneous manifestations in light-exposed areas. The diagnostic criteria were the characteristic macular lesions, the virus transformed keratinocytes on histological examination and the detection of human papillomavirus (HPV) DNA by a nested-PCR approach for EV-associated types. In this case we found HPV-type 5, the most common type of HPV in EV, directly by sequencing and sequence analysis.

In vitro fertilization: increased VLA (very late antigen) integrins and fibronectin after acrosome reaction

The pattern of detectable adhesion molecules (AM) on human ejaculated spermatozoa used for in vitro fertilization (IVF) of human oocytes was evaluated. The percentage of spermatozoa with the alpha chains 3, 4, 5, and 6 of the integrins (also called very late antigens, VLA alpha 3, 4, 5, 6), the alpha V and the beta 3 chains, as well as the matrix proteins laminin and fibronectin, were determined by flow cytometry using monoclonal antibodies against integrins and matrix proteins before and after the acrosome reaction. This reaction was induced by the low-temperature method according to P. Sanchez, E. Töpfer-Petersen, R. J. Aitken, and W. B. Schill (1991, Andrologia 23:197-203) and monitored by the binding of FITC-conjugated Pisum sativum agglutinin. Twenty-three of 34 investigated semen samples fertilized at least one oocyte (fertile group) and 11 samples did not induce a pronucleus formation or cleavage of an oocyte (infertile group). Significant differences in the classical semen parameters between both semen sample groups could be shown only for the percentage of progressively motile spermatozoa (p = .046, U test). The spermatozoa of the fertile group showed a significantly higher expression of VLA alpha 3 (p = .045) and fibronectin (p = .048). Additionally, after the loss of the acrosome a significantly higher expression of alpha 4, alpha 5, and alpha 6 chains of integrins (p < .05) was detected in the fertile semen group. In contrast, the inducibility of the acrosome reaction differed only to a nonsignificant extent (p = .094). These data suggest that spermatozoa showing a higher expression of the alpha chains of the integrins after the acrosome reaction have a better fertilization rate in vitro.

Low expression of adhesion molecules and matrix proteins in patients showing poor penetration in zona-free hamster oocytes

The expression of adhesion molecules and matrix proteins by human spermatozoa as well as their binding to and penetration of zona-free hamster eggs were investigated in 17 patients by means of flow cytometry. Both binding and penetration of hamster oocytes and expression of alpha- and beta-chains of beta 1, beta 3 and beta 4 integrins were determined before and after induction of the acrosome reaction. The expression of the integrin ligands, fibronectin and laminin were also analysed. Significant differences in the expression of very late antigen (VLA) integrins, VLA alpha 4-chain (CD49d), the classical fibronectin receptor VLA alpha 5-chain (CD49e), leukocyte function-associated molecule-3 (LFA-3; CD58) and fibronectin were observed between patients showing good (> 10%) or poor (< 10%) penetration in the sperm penetration assay (P = 0.0068). It is concluded that these adhesion molecules are intimately involved in the sperm-oolemma interaction. Since no differences were observed in either spermiogram parameters or the percentages of acrosome-reacted spermatozoa in the two groups, sperm-oolemma binding and penetration should be regarded as discrete parameters of sperm function.

Recombinant gene expression and 1H NMR characteristics of the kringle (2 + 3) supermodule: spectroscopic/functional individuality of plasminogen kringle domains

The plasminogen kringle 2 (K2HPg) and kringle 3 (K3HPg) modules occur in tandem within the polypeptide segment that affords the heavy chain of plasmin. The K2HPg and K3HPg are unique among the plasminogen kringle domains in that they also are linked to each other via the Cys169-Cys297 (Cys4 of K2HPg to Cys43 of K3HPg, kringle numbering convention) disulfide bridge, thus generating a K2HPg-K3HPg "supermodule". The kringle (2 + 3) sequence of human plasminogen (r-EE[K2HPgK3HPg]DS) was expressed in Escherichia coli, using an expression vector containing the phage T5 promoter/operator N250PSN250P29 and the codons for an N-terminal hexahistidine tag to ensure the isolation of the recombinant protein by affinity chromatography on Ni(2+)-nitrilotriacetic acid/agarose under denaturing and reducing conditions. Kringle (2 + 3) was refolded in the presence of glutathione redox buffer. By taking advantage of the lysine affinity of kringle 2, the protein was purified by affinity chromatography on lysine-Bio-Gel. Recombinant kringle (2 + 3) was identified by amino acid composition, N-terminal sequence and mass determination. The 1H NMR spectrum shows that the intact r-K2HPgK3HPg is properly folded. By reference to spectra of the individual kringles, r-K2HPg and r-K3HPg, resonances of the K2HPg and K3HPg components in the spectrum of the intact r-K2HPgK3HPg can be readily distinguished. The strictly conserved Leu46 residue (kringle residue number convention) yields delta-methyl signals that are characteristic for K2HPg and K3HPg, exhibiting chemical shifts of -0.87 and -0.94 ppm, respectively, which are distinct from those of K1HPg, K4HPg, and K5HPg, (-1.04 to -1.05 ppm). Thus, the high-field Leu46 signals from K2HPg and K3HPg are well resolved from those of other kringles and can be identified unambiguously in spectra of the K1HPgK2HPgK3HPg elastolytic fragment of plasminogen as well as in spectra of Glu-plasminogen. Overall, r-K2HPgK3HPg exhibits broader resonance line widths than does the K1HPg component, consistent with a lesser mobility of the K2HPgK3HPg segment within the K1HPgK2HPgK3HPg fragment, a reflection of the extra structural constraint imposed by the disulfide bridge linking K2HPg to K3HPg. The ligand 6-aminohexanoic acid (6-AHA), which is known to interact with r-K2HPg but not with r-K3HPg, selectively perturbs K2 aromatic signals in the intact r-K2HPgK3HPg spectrum while leaving K3 resonances largely unaffected. Association constant (K(a)) values for 6-AHA determined from 1H NMR ligand titration experiments yield K(a) approximately 2.2 +/- 0.3 mM(-1) for the intact r-K2HPgK3HPg, comparable to K(a) approximately 2.3 +/- 0.2 mM(-1) determined for the isolated r-K2HPg, which demonstrates that the interactions of 6-AHA with the K2HPg ligand-binding site are not significantly affected by the neighboring K3HPg domain within the intact r-K2HPgK3HPg supermodule.

Identification of disulfide bonds in the ninth component (C9) of human complement

C9 is the most abundant protein of the membrane attack complex of complement. By means of limited proteolysis, different chromatographic techniques, a thiol-specific fluorescence assay, amino acid analysis, and Edman degradation 9 out of 12 disulfide bridges are definitely assigned (Cys22-Cys57, Cys33-Cys36, Cys67-Cys73, Cys121-Cys160, Cys233- Cys234, Cys359-Cys384, Cys489-Cys505, Cys492-Cys507, Cys509-Cys518). Weaker evidence permits to reduce the number of possible configurations for the remaining 3 cystines (Cys80-Cys91, Cys86-Cys104, Cys98-Cys113, or Cys80-Cys91, Cys86-Cys113, Cys98-Cys104). These findings are discussed in comparison with the strongly related components C6, C7, C8alpha, and C8beta.