Characterization of ligands for galectins, natural galactoside-binding immunoglobulin G subfractions and sarcolectin and also of the expression of calcyclin in thyroid lesions

The purpose of this study was to characterize ligands for galectins, natural galactoside-binding immunoglobulin G subfractions and sarcolectin and also the expression of calcyclin in various benign and malignant thyroid lesions. The extent of the binding of eight glycochemical probes was quantitatively assessed using computer-assisted microscopy on 76 thyroid lesions including 10 not-otherwise-specified multinodular goiters (S_MNG), 11 multinodular goiters with adenomatous hyperplasia (AH_MNG), 8 normomacrovesicular (NM_ADE) and 12 microvesicular (MIC_ADE) adenomas, and 9 papillary (P_CAR), 10 follicular variants of papillary (FvarP_CAR), 7 follicular (F_CAR) and 9 anaplastic (A_CAR) carcinomas. The 8 histochemical probes included 5 animal lectins (including galectins and sarcolectin), 1 polyclonal antibody (raised against calcyclin) and 2 immunoglobulin G subfractions from human serum with selectivity to alpha- and beta-galactosyl residues. The results show that multinodular goiters with adenomatous hyperplasia exhibited histochemical characteristics intermediate to those of normal multinodular goiters and microvesicular adenomas. Normomacrovesicular adenomas behaved very distinctly from microvesicular ones. Microvesicular adenomas were more closely related to differentiated thyroid carcinomas than any other type of benign thyroid lesions of epithelial origin. Papillary and follicular carcinomas seemed to represent the two extremes of the same biological entity with the follicular variant of the papillary carcinoma serving as a biological link between these two extremes. Anaplastic carcinomas behaved in a significantly different manner when compared to the differentiated forms of thyroid carcinomas. The results suggest that the patterns of expression of the glycoconjugates investigated in the present study may constitute useful tools for characterizing lesions in the human thyroid.

Association of concentration of asbestos and asbestos-like fibers with the patient's survival and the binding capacity of lung parenchyma to galectin-1 and natural alpha-galactoside- and alpha-mannoside-binding immunoglobulin G subfractions from human serum

Our aim in this study was to search for lung parenchyma alterations associated with asbestos and/or asbestos-like fiber concentration. This was done by means of immuno- or glycohistochemistry. The hot-ashing technique determined the asbestos and asbestos-like fiber concentrations in the lung tissues of 100 patients of whom 52 were treated for primary lung and 25 for secondary lung tumors; fiber concentration was also measured for 23 patients whose disease was benign. The results were correlated to smoking habits, survival of the patients, and expression of binding capacities for endogenous lectins, natural carbohydrate-binding and lectin-specific antibodies. The cohort with proven asbestos exposure revealed a mean fiber concentration 114 f/g compared to 95 f/g in the non-exposed group. An increased asbestos fiber concentration was correlated to galectin-1-binding and the presence of epitopes for natural immunoglobulin G subfractions with selectivity to alpha-galactosides and alpha-mannosides. The survival of patients with primary and secondary lung tumors was negatively associated with the fiber concentration. The data indicate that increased presence of asbestos is correlated with an alteration of defined glycohistochemical features of alveolar lining cells.

[A dynamic study on the surgically induced astigmatism after phacoemulsification through three different-sized scleral tunnel incisions]

OBJECTIVE

To compare the changes in the values and directions of surgically induced astigmatism (SIA) after phacoemulsification with three different-sized scleral tunnel incisions and to evaluate their clinical results.

METHODS

The patients were divided into three groups; the length of the scleral tunnel incision was 3.2, 5.5 and 7.0 mm respectively in A, B and C groups. Keratometry measurements were obtained preoperatively, at postoperative 1 week, 1 month and 6 months respectively. SIAs were analyzed by "Cravy vector method". The mean SIA and uncorrected visual acuity were compared among the groups up to 6 months postoperatively.

RESULTS

Eyes in A group displayed significantly less mean SIA and better uncorrected visual acuity than B and C groups at 1 week postoperatively (P < 0.05), but there were no significant differences between any groups at 1 month, 3 months and 6 months postoperatively (P > 0.05). There were no significant differences in the mean SIA and uncorrected visual acuity between B and C groups throughout the whole study period (P > 0.05).

CONCLUSIONS

SIAs in eyes of 3.2 mm incision group of phacoemulsification are less and more stable; a better and quicker rehabilitation of uncorrected visual acuity can be obtained in the early postoperative period.

[Presence of genetic rearrangements in E1/E2 regions of episomal HPV 16 isolates from cervical carcinomas 5-8]

OBJECTIVE

Analysis of genetic situations of E1/E2 region of episomal HPV 16 isolates from cervical carcinomas.

METHODS

Physical statues of HPV 16 DNAs from cervical carcinomas were analyzed by Southern blot hybridization. E1/E2 regions of episomal RPV 16 isolates were amplified by PCR, and the PCR products were cloned and sequenced.

RESULTS

Eight isolates from totally 28 cases showed extrachromosomal HPV 16 DNA. PCR cloned sequence analysis revealed that all the eight isolates contained intact E1/E2 regions, whereas 4 isolates had different ratios of genetic rearrangements, including insertion of E1 repeat sequence and several deletions. Only one case showed the same G deletion at position 1138 as HPV 16 prototype.

CONCLUSIONS

DNA rearrangements were present in E1/E2 regions of episomal HPV 16 isolates from cervical cancers and might play a role in tumorigenesis. Different viral genotypes in an identical tumor tissue might indicate that the tumor occurring at the same position of a patient may derive from two or even more cell clones.

Suppression of metallothionein gene expression in a rat hepatoma because of promoter-specific DNA methylation

Metallothionein I can be induced in response to a variety of agents that include heavy metals and oxidative stress. On the contrary, its induction was suppressed in some lymphoid-derived cancer cells. The mechanism of this repression has not been elucidated. Here, we show silencing of MT-I gene in a solid transplanted rat tumor as a result of promoter methylation at all the 21 CpG dinucleotides that span the region from -225 bp to +1 bp. By contrast, none of these CpG dinucleotides were methylated in the livers from the rats bearing the tumor, which was consistent with the efficient induction of the gene in this tissue by zinc sulfate. Genomic footprinting revealed lack of access of the transcriptional activators to the respective cis-acting elements of the methylated MT-I promoter in the hepatoma. The absence of footprinting was not due to inactivation of the metal regulatory transcription factor MTF-1, because it was highly active in the hepatoma. Treatment of the hepatoma bearing rats with 5-azacytidine, a demethylating agent, induced basal as well as heavy metal-activated MT-I gene expression in the hepatoma, implying that methylation was indeed responsible for silencing the gene. Bisulfite genomic sequencing showed significant (>90%) demethylation of CpG dinucleotides spanning MT-I promoter in the hepatoma following treatment with 5-AzaC. The hypermethylation of MT-I promoter was probably caused by significantly higher (as much as 7-fold) level of DNA methyl transferase activity as well as enhanced expression of its gene in the hepatoma relative to the host liver. These data elucidated for the first time the molecular mechanism for the silencing of a highly inducible gene in a solid tumor transplanted in an animal, as compared with the robust induction in the corresponding parental tissue and have discussed the probable reasons for the suppression of this gene in some tumors.

Bifidobacterium thermacidophilum sp. nov., isolated from an anaerobic digester

A new phenotypic group of Bifidobacterium strains, isolated from an anaerobic digester for the treatment of waste water from a bean-curd farm, was described previously. In this study, the DNA-DNA relatedness between strain 36 (type strain, AS 1.2282T) of this new group and the type strains of other described Bifidobacterium species was analysed. The low level of DNA homology (0-58.9%) as well as comparison of the 16S rDNA sequences confirmed the distinct phylogenetic position of strain 36. In addition, the new species differed from other Bifidobacterium species in its phenotypic characteristics, such as its growth at moderately thermophilic conditions (49.5 degrees C) and at relatively low pH (4.0), as well as its sugar-fermentation pattern. On the basis of phenotypic, genetic and phylogenetic studies, a new Bifidobacterium species, Bifidobacterium thermacidophilum sp. nov., was designated.

[A report on investigation and clinical application of corneal storage media]

OBJECTIVE

To develop intermediate term storage media suitable for Chinese eye banks.

METHODS

Corneal buttons of rabbits were stored in DX solution freshly prepared. After storage for several days, the survival rate of the corneal endothelial cells was examined, enzymohistochemical staining and ultrastructural examinations were carried out for the buttons. Thirty-seven human corneas stored in DX solution for 3 - 11 days were used for corneal transplantation, clinically.

RESULTS

There was no significant difference between rabbit corneal buttons stored in DX sol. and in Optisol in any indices studied. 37 grafts were all transparent in 1 week after transplantation, and the mean endothelial cell density was (2,204.56 +/- 689.56) cells/mm(2).

CONCLUSION

As a safe and efficient intermediate term (about 1 week) storage medium, DX sol. is appropriate for Chinese eye banks.

[Diagnosis and treatment of colorectal non-epithelial malignancies]

OBJECTIVE

To summarize the experience in the diagnosis and treatment of colorectal malignancies of non-epithelial origin.

METHODS

Seventy five cases of colorectal non-epithelial malignancy who had undergone treatment in our hospital from 1975 to 1996 were retrospectively analysed with their clinicopathologic characteristics, treatment and prognosis.

RESULTS

Patients usually had no specific clinical manifectation, such as bloody purulent stool or mucous stool. No apparent mucosa damage other than changes due to pressure from without was found on x-ray and colonoscopic examinations. Diagnosis depended on pathology and clinical manifestations. Metastasis occurred mainly by hematogenous spread and local invasion. In this series, 21 cases (6 liomyosarcomas; 15 lymphosarcoma) had local recurrence. The principle treatment was operation, which was performed two or several times in patients with local recurrences. Except lymphosarcoma, the disease was not sensitive to chemotherapy or radiotherapy. The survival rate was significantly lower than that of colorectal cancers.

CONCLUSION

The disease is apt to be misdiagnosed or missed because it lacks specific symptoms. Local recurrence and hematogenous metastasis are common.

Autoantibodies to DEK oncoprotein in human inflammatory disease

OBJECTIVE

To evaluate the specificity of anti-DEK antibodies for juvenile rheumatoid arthritis (JRA).

METHODS

Anti-DEK autoantibodies were measured by enzyme-linked immunosorbent assay (ELISA) using affinity-purified his6-DEK fusion protein. Sera from 639 subjects (417 patients with systemic autoimmune disease, 13 with sarcoidosis, 44 with pulmonary tuberculosis, 125 with uveitis, and 6 with scleritis, and 34 healthy control subjects) were screened. Reactivity was verified by immunoblotting and immunoprecipitation studies using baculovirus-expressed human DEK.

RESULTS

Anti-DEK activity was found at the following frequencies: JRA 39.4% (n = 71), systemic lupus erythematosus (SLE) 25.1% (n = 216), sarcoidosis 46.2% (n = 13), rheumatoid arthritis 15.5% (n = 71), systemic sclerosis 36.0% (n = 22), polymyositis 6.2% (n = 16), and adult Still's disease 0% (n = 21). Autoantibodies also were detected in 9.1% of tuberculosis sera (n = 44), but were undetectable in sera from the 34 healthy controls. Western blot and immunoprecipitation assay results correlated well with the ELISA findings. In general, levels of anti-DEK autoantibodies were higher in SLE than in other patient subsets, including JRA.

CONCLUSION

Anti-DEK autoantibodies are less specific for JRA than previously believed. They are produced in association with a variety of inflammatory conditions, many of which are associated with granuloma formation and/or predominant Thl cytokine production. Anti-DEK antibodies may be a marker for a subset of autoimmunity associated with interferon-gamma production rather than a particular disease subset.

Modification of the amino terminus of a class II epitope confers resistance to degradation by CD13 on dendritic cells and enhances presentation to T cells

Dendritic cells and human B cell lines were compared for ability to present synthetic peptides corresponding to residues 145-159 and 188-203 of human Ig kappa-chains to peptide-specific mouse T cell hybridomas restricted by HLA-DR4Dw4. B cell lines presented both peptides, but dendritic cells could only efficiently present the latter epitope. In this paper, we show that dendritic cells degrade the 145-159 peptide, removing four residues from the amino terminus. Binding of the peptide to the class II restriction element is not required for this process. The degradation product is resistant to further cleavage, accumulates in the culture supernatant, and does not bind to HLA-DR4Dw4 or stimulate T cell reactivity. Cleavage can be blocked with bestatin, but not with other protease inhibitors tested, or by a mAb directed against aminopeptidase N (CD13). Addition of an acetyl group to the amino terminus of peptide 145-159 also blocks degradation, and allows dendritic cells to present the peptide to specific T cells with greatly increased efficiency. These results demonstrate that CD13 on dendritic cells is able to selectively and efficiently degrade exogenously provided peptide Ags, in a process that can be blocked by addition of an acetyl group to the amino terminus of the peptide. Modification of the amino terminus of peptide epitopes susceptible to degradation may prove to be useful as a general strategy for enhancing their immunogenicity.

[Experimental study on herpes simplex virus-1 functional gene latency in cornea]

OBJECTIVE

To investigate the possible existence of herpes simplex virus-1 (HSV-1) functional gene latency in cornea.

METHODS

A herpes simplex keratitis (HSK) model was established in New Zealand White (NZW) rabbit corneas, latently infected corneas were transplanted to one eye of each naive NZW rabbit. One week after the operation, the corneal buttons were removed and divided into three portions. One portion was processed for HSV-1 antigen detection, another was for HVS-1 latency associated transcript (LAT), thymidine kinase (TK) and DNA polymerase gene detections by polymerase chain reaction (PCR), and the last portion after tissue culture for 3 weeks, it was co-cultured with rabbit kidney cells (RK) for one week, then the expression of HSV-1 antigen in the RK cells and this portion of corneal button was detected.

RESULT

In the 15 corneal samples negative for HSV-1 antigen, LAT gene was detected in 8 samples, TK gene in 10 and DNA polymerase gene in 6 samples. HSV-1 antigen was detected in 3 samples of RK cells and 6 cultured corneal samples.

CONCLUSION

HSV-1 functional genes are retained in latently infected cornea.

[No switch region is found in the regulatory sequence of HPV 16 for promoter P97]

OBJECTIVE

Cellular transcriptional regulatory factor YY1 represses the activity of the early promoter P97 of HPV 16, but the regulatory activity to early promoter P105 of HPV 18 depends on a switch region which locates at the upstream sequences of YY1 binding sites. This study is to find out whether within the HPV 16 LCR there is such motif.

METHODS

DNA sequences of the whole HPV 16 LCR region were analyzed. Two similar switch structures were found. Different CAT reporter plasmids, one containing HPV 16 reference and the other mutated LCRs, both starting at the end of L1 and from the beginning of the enhancer, were generated and transfected in HeLa cells transiently.

RESULTS

CAT assays showed there is no change of regulation pattern of YY1 on P97, when the two switch-similar structures were deleted. Sequences analysis also showed that no switch region like motif could be demonstrated in enhancer region, in promoter proximal segment, and even in E6/E7 area.

CONCLUSION

It suggests that there is no such switch region within HPV 16 transcriptional regulatory region.

Immunotherapy of NOD mice with bone marrow-derived dendritic cells

We evaluated two bone marrow-derived dendritic cell (DC) populations from NOD mice, the murine model for type 1 human diabetes. DCs derived from GM-CSF [granulocyte/macrophage colony-stimulating factor] + interleukin (IL)-4 cultures expressed high levels of major histocompatibility complex (MHC) class II, CD40, CD80, and CD86 molecules and were efficient stimulators of naive allogeneic T-cells. In contrast, DCs derived from GM-CSF cultures had low levels of MHC class II costimulation/activation molecules, were able to take up mannosylated bovine serum albumin more efficiently than GM + IL-4 DCs, and were poor T-cell stimulators. The two DC populations migrated to the spleen and pancreas after intravenous injection. To determine the ability of the two DC populations to modulate diabetes development, DCs were pulsed with a mixture of three islet antigen-derived peptides or with medium before injection into prediabetic NOD mice. Despite phenotypic and functional differences in vitro, both populations prevented in vivo diabetes development. Pulsing of the DCs with peptide in vitro did not significantly improve the ability of DCs to prevent disease, which suggests that DCs may process and present antigen to T-cells in vivo. In addition, we detected GAD65 peptide-specific IgG1 antibody responses in DC-treated mice. Overall, these results suggest that a Th2 response was generated in DC-treated mice. This response was optimal when using GM + IL-4 DCs, which suggests that the balance between regulatory Th2 and effector Th1 cells may have been altered in these mice.

Binding and uptake of agalactosyl IgG by mannose receptor on macrophages and dendritic cells

Increased levels of agalactosyl IgG (G0 IgG) are found in several autoimmune diseases, including rheumatoid arthritis, in which they are correlated with severity of the disease. To investigate whether structural alteration of IgG may lead to aberrant processing and presentation of IgG peptides as autoantigens, we have studied uptake of G0 IgG by human dendritic cells and macrophages cultured from PBMC. We found that enzymatic removal of terminal galactose residues, which exposes N-acetylglucosamine residues, increases uptake of soluble IgG mediated by mannose receptor on macrophages and dendritic cells. Efficient uptake appears to require recycling of the receptor, can be blocked by saccharides or Abs reactive with mannose receptor, and is dependent upon the state of maturation of the dendritic cells. No differences between IgG isotypes in ability to be internalized by APC were identified, suggesting that uptake would not be limited to a particular subset of Abs. These results suggest a novel pathway by which Abs or Ag-Ab complexes can be taken into dendritic cells and macrophages, and potentially generate epitopes recognized by T cells. These findings may have particular relevance for autoimmune disorders characterized by high levels of G0 IgG.

The terminal structure plays an important role in the biological activity of cecropin CMIV

Antibacterial peptides have received increasing attention as a new pharmaceutical substance. But the molecular mechanism of lysis is still poorly understood. CMIV gene and mutant CMIV gene in GST fusion system were expressed. After cleaving with different cleavage reagents, the peptide with an excess of N-terminus and with an un-amidated C-terminus stopped the activity while the peptide with an excess Asn at the C-terminus had the activity level the same as natural CMIV. The results showed that the terminal structure of cecropin CMIV played an important role in its biological activity.

Erf2, a novel gene product that affects the localization and palmitoylation of Ras2 in Saccharomyces cerevisiae

Plasma membrane localization of Ras requires posttranslational addition of farnesyl and palmitoyl lipid moieties to a C-terminal CaaX motif (C is cysteine, a is any aliphatic residue, X is the carboxy terminal residue). To better understand the relationship between posttranslational processing and the subcellular localization of Ras, a yeast genetic screen was undertaken based on the loss of function of a palmitoylation-dependent RAS2 allele. Mutations were identified in an uncharacterized open reading frame (YLR246w) that we have designated ERF2 and a previously described suppressor of hyperactive Ras, SHR5. ERF2 encodes a 41-kDa protein with four predicted transmembrane (TM) segments and a motif consisting of the amino acids Asp-His-His-Cys (DHHC) within a cysteine-rich domain (CRD), called DHHC-CRD. Mutations within the DHHC-CRD abolish Erf2 function. Subcellular fractionation and immunolocalization experiments reveal that Erf2 tagged with a triply iterated hemagglutinin epitope is an integral membrane protein that colocalizes with the yeast endoplasmic reticulum marker Kar2. Strains lacking ERF2 are viable, but they have a synthetic growth defect in the absence of RAS2 and partially suppress the heat shock sensitivity resulting from expression of the hyperactive RAS2(V19) allele. Ras2 proteins expressed in an erf2Delta strain have a reduced level of palmitoylation and are partially mislocalized to the vacuole. Based on these observations, we propose that Erf2 is a component of a previously uncharacterized Ras subcellular localization pathway. Putative members of an Erf2 family of proteins have been uncovered in yeast, plant, worm, insect, and mammalian genome databases, suggesting that Erf2 plays a role in Ras localization in all eucaryotes.

[Determination of diosgenin in Rhizoma Paridis by high performance liquid chromatography]

A method for the separation and determination of diosgenin in Rhizoma Paridis by reversed-phase high performance liquid chromatography was developed. The Rhizoma Paridis powder samples were extracted with methanol in a Soxhlet extractor. After extraction the solvent was evaporated and the extract was hydrolysed with 2 mol/L hydrochloric acid for 2 h in a boiling water bath. Then the diosgenin was extracted with petroleum ether (b.p. 60-90 degrees C). The operating conditions were Symmetry C8 column (5 microns, 3.9 mm x 150 mm) at 30 degrees C, mobile phase of V(acetonitrile):V(water) = 75:25 and UV detector at 203 nm. The linearity of the calibration curve was good in the range of 2.1-10.5 micrograms for diosgenin(r = 0.9994). The average recovery and RSD of diosgenin were 99.1% and 1.7% (n = 5) respectively. The method is accurate and reproducible and has been applied to the analysis of Rhizoma Paridis from different sources.

Identification and cloning of a negative regulator of systemic acquired resistance, SNI1, through a screen for suppressors of npr1-1

Systemic acquired resistance (SAR) is a plant immune response induced after a local infection by necrotizing pathogens. The Arabidopsis NPR1 gene is a positive regulator of SAR, essential for transducing the SAR signal salicylic acid (SA). Mutations in the NPR1 gene abolish the SA-induced expression of pathogenesis-related (PR) genes and resistance to pathogens. To identify additional regulators of SAR, we screened for suppressors of npr1-1. In the npr1-1 background, the sni1 (suppressor of npr1-1, inducible 1) mutant shows near wild-type levels of PR1 expression and resistance to pathogens after induction. Restoration of SAR in npr1-1 by the recessive sni1 mutation indicates that wild-type SNI1 may function as a negative regulator of SAR. We cloned the SNI1 gene and found that it encodes a leucine-rich nuclear protein.

[Measurement of retinal nerve fiber layer thickness of normal eyes with nerve fiber analyzer]

OBJECTIVE

To study the retinal nerve fiber layer thickness (RNFLT) of normal eye and the correlation with age.

METHODS

RNFLT of 198 cases of normal eyes were examined by using nerve fiber analyzer (NFA).

RESULTS

There were significant inverse linear correlation between the RNFLT and age (r = -0.46, P < 0.01). In the analysis by the quadrant, the RNFLT was correlated with age in the superior and inferior quadrant. The mean ratio of superior and inferior quadrant thickness (S/I) was 1.041.

CONCLUSION

NFA seems to be an useful tool to measure the RNFLT quantitatively. The RNFLT of normal eye is found to be decreased with age.

[Expression of human prp gene in prokaryotic cells using GST fusion protein expression system]

OBJECTIVE

To study the biological features of cell-surface protein PrPc, which is thought to be involved in the prion-associated diseases after converting to a proteinase-resistant isoform PrPSc posttranslationally, and to establish an effective immunologic diagnostic method using PrPc as antigen.

METHODS

Amplifying and cloning the human prp gene from lymphocytes of two normal Chinese, after confirmed by DNA sequence analysis, the genes were separately subcloned into a GST-fusion expression plasmid.

RESULTS

Sequence analysis showed that one contatined a point mutation that induced the 65th amino acid "Trp" inverting to a stop codon "TAG", whereas the other had the same sequence as the published standard prp gene. Both the standard and the mutated prp genes were separately subcloned into a GST fusion protein expression vector and expressed in the prokaryotic cells effectively. Western blot assay revealed that both of them expressed GST-PrP fusion proteins and could be recognized by PrP specific monoclonal antibody.

CONCLUSION

It suggests that human PrP protein can be expressed in the GST fusion protein expression system and the expressed proteins hold good immune-reactivity.

SSA/Ro antigen expressed on membrane of UVB-induced apoptotic keratinocytes is pathogenic but not detectable in supernatant of cell culture

OBJECTIVES

To better understand the potential effect of ultraviolet light on the photosensitivity of patients with lupus erythematosus (LE), to elucidate the mechanisms of SSA/Ro antibody formation after UV exposure, and to investigate the role of this autoantibody in the pathogenesis of skin lesions.

METHODS

Primary human keratinocytes were cultured in Medium-154. After ultraviolet-B light (UVB) irradiation, the keratinocytes were treated with affinity-purified anti-SSA/Ro sera and stained with FITC-labeled goat-anti-human IgG and propidium iodide (PI), followed by enzyme digestion with RNase, RNase-free DNase or RNase plus DNase. As target cells, the irradiated keratinocytes were incubated with affinity-purified anti-SSA/Ro sera, with or without fresh human sera as complement. The supernatants of irradiated keratinocytes were analyzed with ELISA method for SSA/Ro antigens.

RESULTS

UVB irradiation induced apoptotic blebs on the cell surface. The blebs were composed of ribonucleoproteins and contained SSA/Ro antigens. SSA/Ro antigens expressed on UVB irradiated keratinocytes bound to affinity-purified anti-SSA/Ro sera, leading to complement-dependent cytotoxicity. However, no SSA/Ro antigens were detected in the supernatants.

CONCLUSIONS

SSA/Ro, a ribonucleoprotein antigen expressed on UVB irradiated keratinocytes, may be recognized and presented to immune cells by a direct cell-cell contact other than be eliminated into the circulation.

Interaction of NPR1 with basic leucine zipper protein transcription factors that bind sequences required for salicylic acid induction of the PR-1 gene

The Arabidopsis thaliana NPR1 has been shown to be a key regulator of gene expression during the onset of a plant disease-resistance response known as systemic acquired resistance. The npr1 mutant plants fail to respond to systemic acquired resistance-inducing signals such as salicylic acid (SA), or express SA-induced pathogenesis-related (PR) genes. Using NPR1 as bait in a yeast two-hybrid screen, we identified a subclass of transcription factors in the basic leucine zipper protein family (AHBP-1b and TGA6) and showed that they interact specifically in yeast and in vitro with NPR1. Point mutations that abolish the NPR1 function in A. thaliana also impair the interactions between NPR1 and the transcription factors in the yeast two-hybrid assay. Furthermore, a gel mobility shift assay showed that the purified transcription factor protein, AHBP-1b, binds specifically to an SA-responsive promoter element of the A. thaliana PR-1 gene. These data suggest that NPR1 may regulate PR-1 gene expression by interacting with a subclass of basic leucine zipper protein transcription factors.

Solid-phase synthesis of a combinatorial array of 1,3-bis(acylamino)-2-butanones, inhibitors of the cysteine proteases cathepsins K and L

To more rapidly prepare members of the 1,3-bis(acylamino)-2-butanone class of cysteine protease inhibitors, a solid-phase synthesis was developed. 1-Azido-3-amino-2,2-dimethoxybutane (4), which has the two amino groups differentiated and the ketone protected as a a ketal, served as a surrogate for the 1,3-diamino-2-butanone core. Amine (4) was coupled to the BAL-resin-linked carboxylic acids derived from alpha-amino acid esters. Evaluation of a small combinatorial array by measuring inhibition constants (Ki,appS) against cathepsins K, L, and B provided some structure-activity relationship trends with respect to selectivity and potency. Novel, potent inhibitors of cathepsins K and L were identified.

ebi regulates epidermal growth factor receptor signaling pathways in Drosophila

ebi regulates the epidermal growth factor receptor (EGFR) signaling pathway at multiple steps in Drosophila development. Mutations in ebi and Egfr lead to similar phenotypes and show genetic interactions. However, ebi does not show genetic interactions with other RTKs (e.g., torso) or with components of the canonical Ras/MAP kinase pathway. ebi encodes an evolutionarily conserved protein with a unique amino terminus, distantly related to F-box sequences, and six tandemly arranged carboxy-terminal WD40 repeats. The existence of closely related proteins in yeast, plants, and humans suggests that ebi functions in a highly conserved biochemical pathway. Proteins with related structures regulate protein degradation. Similarly, in the developing eye, ebi promotes EGFR-dependent down-regulation of Tramtrack88, an antagonist of neuronal development.