Phosphoproteomic identification of a PDX-1/14-3-3ε interaction in pancreatic beta cells

Glucose-dependent activation of the homeodomain transcription factor PDX-1 leads to its phosphorylation, to an increase in DNA binding capacity, and to NLS dependent translocation into the nucleus. To uncover unknown mediators of PDX-1 activation, PDX-1 interacting proteins were analysed by pull-down from (32)P-labelled, glucose-stimulated MIN6 cells. Recovered proteins were analysed by 2D gel electrophoresis and mass spectrometry. We identified 14-3-3ε as a novel PDX-1 binding protein and confirmed the interaction in vivo by Fluorescence Resonance Energy Transfer (FRET) analysis. We propose that 14-3-3ε interacts directly with PDX-1 to regulate its cellular distribution in pancreatic beta cells.

Formation of N,N-Dimethylglycine, Acetic Acid, and Butyric Acid from Betaine by Eubacterium limosum

Two bacterial strains that grow anaerobically on betaine were isolated from enrichment cultures and identified as strains of Eubacterium limosum. In a mineral medium supplemented with yeast extract and Casitone, the doubling time of E. limosum strain 11A on betaine was 6 h at 37 degrees C. The molar growth yield amounted to 9 g of dry cell mass per mol. Betaine was fermented in accordance with the following equation: 7 betaine + 2 CO(2) --> 7 N,N-dimethylglycine + 1.5 acetate + 1.5 butyrate. E. limosum also grew on methanol and choline. The former was converted to acetate and butyrate, and the latter was converted to N,N-dimethylethanolamine, acetate, and butyrate. The conditions for the quantitative determination of N,N-dimethylglycine by capillary tube isotachophoresis have been determined.

[Interferon-alpha as treatment option in severe persistent uncontrolled bronchial asthma: an open label study]

BACKGROUND

The purpose of this study was to evaluate the long-term safety and therapeutic effects of IFN-alpha in patients with severe persistent uncontrolled asthma on long-term oral glucocorticoid (GC) treatment.

PATIENTS AND METHODS

The study included 16 patients (2 male, 14 female; age 39 years [range: 24 - 63]) with severe persistent asthma. Diagnosis and severity classification of asthma were established according to the guidelines of the "Deutsche Atemwegsliga". Eight patients stopped the therapy within 7 months due to side effects (n = 3), costs not covered by health insurance (n = 2), non-compliance (n = 2), and change of residence (n = 1). 8 patients (8 female, age 49 years [range: 35 - 68], duration of disease 16 years [range: 5 - 24]) were treated for at least 12 months with IFN-alpha (9 microg) 3 times/week. All patients were on oral glucocorticoids (GCs) for more than 5 years (average dose 17.5 [range: 5.0 - 64.0] mg/d). Clinical signs, lung function, need for reliever medication, number of emergency visits and hospitalisations and diary were assessed prior to and after 12 months of treatment. Data are given as percent of normal or median [range].

RESULTS

IFN-alpha improved lung function after 12 months: FEV1 64 vs. 75 %; FEV1/IVC 76 vs. 89 %; RV 153 % vs. 129 %; Rtot 193 vs. 111 % and morning PEF by 50 - 190 L/min. IFN-alpha also significantly reduced the use of reliever medication (10 [2 - 20] vs. 1 [0 - 3] puffs/d), nocturnal awakening (11 [4 - 30] vs. 1 [0 - 5]/month), emergency visits (7 [2 - 15] vs. 0 [0 - 5]/month) and hospitalisations (4 [1 - 8] vs. 0 [0 - 5]/year). In 5 patients the asthma attacks and nightly disturbances disappeared completely. The improvements were achieved despite a tapering of the oral GCs in all patients from 17.5 (5.0 - 64.0) to 2 (0 - 16) mg/d. In 5 patients GC treatment could be discontinued. The number of blood eosinophils decreased from 0.46 to 0.28 Gpt/L. Adverse events were transient and usually decreased within 3 to 4 weeks. Two patients developed an autoimmune thyreoiditis.

CONCLUSION

In severe persistent, uncontrolled, and GC-dependent asthma, treatment with IFN-alpha leads to sustained clinical improvement and allows the reduction or discontinuation of oral GCs. Severe side effects may occur in isolated cases.

[Establishing a protein signature from prostate tissue biopsies]

The prostate-specific antigen test (PSA) has been a major factor contributing to a better management of prostate cancer. The low specificity limits its use in diagnosis especially in early detection of prostate cancer. Multiply expressed proteins need to be identified to establish a disease-specific protein signature that distinguishes between cancerous and noncancerous tissue. The first aim of our study is to identify differentially expressed proteins in both tissues using two-dimensional gel electrophoresis and subsequent mass spectrometry. We elucidated whether prostate biopsies are useful. First results have shown a different protein expression pattern in cancerous and noncancerous tissue. PCR revealed an increasing amount of mRNA for some upregulated proteins. We conclude that biopsies are useful material to establish protein expression patterns.

Global proteome analysis of germ cell tumor (GCT) cell lines under treatment with cisplatin (CDDP)

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Background: GCTs are the most common malignancy in young Caucasian males aged 20–40. With CDDP-based chemotherapy, highly effective treatment has been developed for the majority of patients with GCT. However, the molecular mechanisms underlying treatment response remain elusive. Therefore, we used a global proteomics approach to screen for changes induced in GCT cell lines by CDDP. Material and Methods: Global protein expression analysis of three GCT cell lines, NTERA2, 2102EP, and NCCIT, both untreated and treated with CDDP for 48 hours at the IC50, was performed using 2-dimensional gel electrophoresis. Differentially expressed proteins were analyzed using matrix-assisted laser desorption/ionization - time of flight (MALDI TOF) and Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Identification of proteins was performed using peptide mass-fingerprinting and NCBI/SwissProt and The Global Proteome Machine database search. Results: In total, 66 proteins were found to be differentially expressed comparing untreated and treated cells. Numbers of proteins showing upregulation under CDDP were 18 in NTERA2, 10 in NCCIT, and 9 in 2102EP, whereas 17 proteins were downregulated in NTERA2, 5 in NCCIT, and 7 in 2102EP. Identification of corresponding proteins was successful in 44 out of 66 spots (67%). Differential expression of 5 proteins was found in more than one cell line. One protein (Enolase 1) was consistently up-regulated in all three cell lines under CDDP. The identified proteins can be grouped into different categories: 15 are involved in DNA-binding/transcription, 8 in metabolism, 8 in protein folding/binding/chaperone, 6 in cell signaling/differentiation, 4 in apoptosis, and 3 in cytoskeleton/cell movement. Conclusion: The results of this screening approach identify factors differentially regulated during response to CDDP in GCTs, and reveal a specific response pattern for each cell line. This knowledge can help to identify therapeutic targets and factors potentially involved in treatment sensitivity and resistance.

No significant financial relationships to disclose.

Inhibition of BCL11B expression leads to apoptosis of malignant but not normal mature T cells

The B-cell chronic lymphocytic leukemia (CLL)/lymphoma 11B gene (BCL11B) encodes a Krüppel-like zinc-finger protein, which plays a crucial role in thymopoiesis and has been associated with hematopoietic malignancies. It was hypothesized that BCL11B may act as a tumor-suppressor gene, but its precise function has not yet been elucidated. Here, we demonstrate that the survival of human T-cell leukemia and lymphoma cell lines is critically dependent on Bcl11b. Suppression of Bcl11b by RNA interference selectively induced apoptosis in transformed T cells whereas normal mature T cells remained unaffected. The apoptosis was effected by simultaneous activation of death receptor-mediated and intrinsic apoptotic pathways, most likely as a result of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) upregulation and suppression of the Bcl-xL antiapoptotic protein. Our data indicate an antiapoptotic function of Bcl11b. The resistance of normal mature T lymphocytes to Bcl11b suppression-induced apoptosis and restricted expression pattern make it an attractive therapeutic target in T-cell malignancies.

Tumor necrosis factor alpha induces the expression of the nuclear protein p8 via a novel NF kappaB binding site within the promoter

p8 is a widely expressed HMG-I/Y-like transcription factor which is involved in regulating cell proliferation and tissue stress. Several studies describe a strong upregulation of p8 expression during inflammatory processes like pancreatitis and LPS-induced sepsis. Here we demonstrate that TNFalpha, which is an important inducer of innate defence against gram-negative bacteria, significantly stimulates p8 protein production in H4IIE rat hepatoma cells within 2 hours. Since a putative NF kappaB motif has been described, we further tested whether TNFalpha stimulates p8 expression via activation of NF kappaB. We characterized the TNFalpha-induced binding of NF kappaB to this motif. We show that the TNFalpha-induced NF kappaB pathway contributes to the induction of p8 during pancreatitis and LPS-induced inflammation.

A Monte Carlo-based model for steady-state diffuse reflectance spectrometry in human skin: estimation of carbon monoxide concentration in livor mortis

In terms of physics, the skin can be regarded as an optically turbid medium in which the light is mainly scattered by the collagen fibers, mitochondria and cell nuclei, whereas the absorption is determined by the content of reduced hemoglobin, oxyhemoglobin, bilirubin, and melanin. When the measuring geometry and the illumination spectrum are known, the optical characteristics of the skin can be approximately described by the diffusion and absorption coefficients. These values define the diffusion and absorption probability per unit distance traveled for each wavelength. Based on these parameters, a mathematical skin model was developed with the help of Monte Carlo simulations. By implementing the absorption coefficient of carbon monoxide hemoglobin (CO-Hb) into the skin model, the authors wanted to investigate whether this method is suitable to determine the CO-Hb concentration from spectral reflectance curves of livores. The investigations performed on 28 deaths from CO poisoning so far showed that this is generally possible. In almost all cases, the actual CO-Hb values could be estimated correctly by using the Monte Carlo simulations.

Expression of thyroid hormone receptor isoform alpha1 in pancreatic islets

Thyroid hormone receptors (TR) mediate the action of thyroid hormones. Genetic studies revealed that the individual TR isoforms possess different functions. In the present paper we studied the expression of the isoforms TRalpha1 and TRbeta1 in the murine pancreatic islet. TRalpha1 and TRbeta1 mRNA transcripts and proteins were detected in islets using reverse transcription-polymerase chain reaction and Western blotting analyses, respectively. In immunohistochemical studies individual cells in the periphery of islets were labelled using an anti-TRalpha1 antibody. No labelled cells were detected in the exocrine pancreas. A similar staining pattern was obtained with an anti-glucagon antibody, but not with an anti-insulin antibody, which suggests that TRalpha1 is mainly expressed in alpha-cells. In order to address a potential function of TRalpha1 in this cell type, the regulation of glucagon gene expression by triiodothyronine was studied in a glucagon-producing cell line by Northern blot analysis and transient transfection assays using glucagon promoter luciferase fusion gene constructs. In these assays, triiodothyronine did not regulate the glucagon mRNA level or the glucagon promoter activity. The predominant localization of TRalpha1 in pancreatic alpha-cells suggests that this receptor isoform mediates a specific, yet unknown, function of thyroid hormones in this cell type.

Cerebral beta-amyloid deposition is augmented by the -491AA promoter polymorphism in non-demented elderly individuals bearing the apolipoprotein E epsilon4 allele

The apolipoprotein E epsilon4 allele (APOE, gene; apoE, protein) is widely accepted as a risk factor for Alzheimer's disease (AD). Our previous studies found that APOEepsilon4 promotes AD pathogenesis by fostering the early deposition of the amyloidogenic peptide Abeta in the aging brain. Recent reports suggest that polymorphisms in the upstream promoter region of APOE differentially affect the production of apoE and also may have an important influence on the probability of developing AD. In this study, we asked whether APOE promoter -491 (A/T) variants interact with APOE polymorphisms to modulate the degree of beta-amyloid- and tau-related pathology in the medial temporal lobe of the non-demented elderly. Our results confirm that APOEepsilon4 is associated with increased formation of senile plaques, cerebrovascular amyloid, and neurofibrillary tangles in the medial temporal lobe. We also found that homozygosity for A at position -491 of the APOE promoter (-491AA) correlates with increased Abeta17-24 and Abeta42 deposition in APOEepsilon4-positive cases, but not in cases lacking the epsilon4 allele. In comparison, Abeta burden is significantly less in epsilon4 carriers with the -491AT and -491TT promoter allelotypes. There was no effect of -491 polymorphisms on Abeta40 deposition (which is relatively sparse in the non-demented elderly), on the number of activated microglia, or on the amount of neurofibrillary tangles. We conclude that the amyloidogenic effects of apoE4 are exacerbated by polymorphisms in the APOE promoter that enhance apoE production.

Oxidative and nitrosative stress induces peroxiredoxins in pancreatic beta cells

AIMS/HYPOTHESIS

Insulin-producing beta cells are destroyed by oxidative and nitrosative stress during the pathogenesis of Type I (insulin-dependent) diabetes mellitus. These cells are more sensitive than others due to their deficiency of well known antioxidant enzymes like superoxide dismutase, glutathione peroxidase and catalase. However the peroxiredoxins discovered in the past decade form a large family of highly conserved thioredoxin-dependent peroxide reductases, which are present in most tissues. We investigated whether peroxiredoxins I and II are present in pancreatic beta cells and if they are inducible by oxidative and nitrosative stress.

METHODS

To detect these enzymes in insulin-producing beta cells we used semiquantitative RT-PCR, western blots and immunohistochemistry. The expression of peroxiredoxins I and II was analysed after treatment with cytokines, hydrogen peroxide, alloxan or streptozotocin in the rat insulinoma cells INS-1 using RT-PCR and western blots.

RESULTS

We show that peroxiredoxins I and II are present in the cytoplasm of pancreatic islet cells as well as in insulinoma cell lines beta TC6-F7 and INS-1. Peroxiredoxins I and II were up-regulated by all stress agents used.

CONCLUSION/INTERPRETATION

Beta cells, undersupplied with well characterized antioxidant enzymes, possess an additional antioxidant system which is inducible by oxidative as well as nitrosative stress.

Activated microglia do not mediate the early deposition of Abeta in carriers of the apolipoprotein Eepsilon4 allele

Activated microglia are a prominent component of the senile plaques in end-stage Alzheimer's disease, but whether microglia contribute to the initiation of the lesions remains unknown. In a previous postmortem study of non-demented elderly cases, we found that amyloidogenesis is advanced by at least 10 years in carriers of the apoEepsilon4 allele. To determine whether microglia are involved in the initial stages of beta-amyloid pathogenesis and whether apoE genotype influences microglial activation, we quantified HLA-DR-immunoreactive microglia in the medial temporal lobe of 229 non-demented humans of various APOE genotypes who had died between 50 and 91 years of age. Our results show that the number of HLA-DR-immunoreactive microglia increases with advancing age in both the gray matter and the white matter. In contrast to amyloid plaques and neurofibrillary tangles, there is no significant correlation between apoE genotype and density of microglia, although apoEepsilon4 homozygotes tended to have more microglia than did other apoE groups. In sections double-immunostained for Abeta and activated microglia, activated microglia were associated with dense-cored plaques but not with diffuse plaques, suggesting that microglial activation is a relatively late event in the genesis of beta-amyloid. Activation of microglia thus appears not to be the initial impetus for Abeta-deposition in the elderly.

Tumour-related enzyme alterations in the clear cell type of human renal cell carcinoma identified by two-dimensional gel electrophoresis

To identify tumour-related enzyme alterations we have used 2D-gels to analyse the proteome from dissected malignant and benign kidney areas from patients with clear-cell-type renal carcinoma. The expression of 12 proteins was diminished in tumour. Four proteins were characterized by mass spectrometry and were identified as enoyl-CoA hydratase, alpha-glycerol-3-phosphate dehydrogenase, aldehyde dehydrogenase 1 and aminoacylase-I.

Basal level glucose-6-phosphatase gene transcription requires binding sites for Sp family proteins within the gene promoter

The significance of two regions (SpA: -19 to -11 and SpB: -63 to -55) within the human glucose-6-phosphatase (G6Pase) gene promoter for gene expression was examined. The mutation of SpA and SpB together, but not alone, decreased G6Pase promoter activity. Electromobility shift assays showed that SpA and SpB were able to bind the transcription factors Sp1 and Sp3.

Phorbol ester-induced activation of mitogen-activated protein kinase/extracellular-signal-regulated kinase kinase and extracellular-signal-regulated protein kinase decreases glucose-6-phosphatase gene expression

Glucose-6-phosphatase (G6Pase) plays a central role in blood glucose homoeostasis, and insulin suppresses G6Pase gene expression by the activation of phosphoinositide 3-kinase (PI 3-kinase). Here, we show that the phorbol ester PMA decreases both basal and dexamethasone/cAMP-induced expression of a luciferase gene under the control of the G6Pase promoter in transiently transfected H4IIE hepatoma cells. This regulation was suppressed by the inhibitors of the mitogen-activated protein kinase/extracellular-signal-regulated kinase kinase (MEK), PD98059 and U0126, but not by the inhibitor of PI 3-kinase, LY294002. The co-expression of a constitutively active mutant of MEK mimicked the regulation of G6Pase promoter activity by PMA. The effect of PMA on both basal and induced G6Pase gene transcription was impaired by the overexpression of a dominant negative MEK construct, as well as by the expression of mitogen-activated protein kinase phosphatase-1. The mutation of the forkhead-binding sites within the insulin-response unit of the G6Pase promoter, which decreases the effect of insulin on G6Pase gene expression, did not alter the regulation of gene expression by PMA. The data show that PMA decreases G6Pase gene expression by the activation of MEK and extracellular-signal regulated protein kinase. With that, PMA mimics the effect of insulin on G6Pase gene expression by a different signalling pathway.

Differential regulation of endogenous glucose-6-phosphatase and phosphoenolpyruvate carboxykinase gene expression by the forkhead transcription factor FKHR in H4IIE-hepatoma cells

The insulin responsive H4IIEC3 rat hepatoma cell line (H4 cells) was used in order to determine the role of the transcription factor FKHR in the regulation of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase). Both PEPCK and G6Pase contain putative FKHR binding sites in their promoter sequence. Using a retroviral expression system, we stably overexpressed FKHR in H4-cells. FKHR was phosphorylated in a PI 3-kinase- and Akt-dependent manner, and was translocated from the nucleus to the cytoplasm in response to insulin. Furthermore, overexpression of FKHR markedly increased the expression of the catalytic subunit of G6Pase (basal about 2.5-fold, dexamethasone/cAMP stimulated about fivefold, respectively). In contrast, both basal and dexamethasone/cAMP-induced levels of PEPCK mRNA were unaffected by FKHR-overexpression. These data suggest a specific function for FKHR in the regulation of hepatic gluconeogenesis at the level of G6Pase, but not PEPCK gene expression.

Differential expression of the subunits of the glucose-6-phosphatase system in the clear cell type of human renal cell carcinoma - no evidence for an overexpression of protein kinase B

The expression of two components of the glucose-6-phosphatase system, the catalytic subunit (G6PaseC) and the glucose-6-phosphate transporter, was analyzed in the clear cell type of human renal cell carcinoma. The expression of G6PaseC was decreased in tumours compared with non-tumourous tissue of the same patient. The expression of G6PaseT varied with no general trend between tumours and control tissue. The expression of protein kinase B (PKB) was unchanged in the tumours, suggesting that the down-regulation of G6PaseC in clear cells and the maintenance of the transformed phenotype are not predominantly caused by an overexpression of PKB.

An analytical model for the SO2- centre, ESR signal at g = 2.0057 in carbonates

Detailed experiments were conducted to test the behaviour of the ESR signal at the g-value of 2.0057 in corals after irradiation and heating. On the basis of the results an analytical model for this signal was developed. We assume the existence of a precursor to the SO2- radical. On irradiation traps are produced, some in the precursor state and some in the radical state. Heating then causes transfer of electrons into the precursor state, from the precursor state into the radical state and out of the radical state into a base state. On the base of this model, we suggest that the signal at g = 2.0057 can be applied for dating. Our first dating attempts on corals delivered promising results for the suggested procedure.

The Tet-On system in transgenic mice: inhibition of the mouse pdx-1 gene activity by antisense RNA expression in pancreatic beta-cells

To elucidate the function of pancreas duodenal homeobox 1 (PDX-1; insulin promoter factor 1/somatostatin transcription factor 1/islet duodenum homeobox 1/insulin upstream factor 1) in differentiated beta-cells of adult animals we generated transgenic mice using the Tet-On system. Inducible expression of an antisense RNA should down-regulate the PDX-1 protein. The selective and continuous inhibition of PDX-1 gene expression should impair the expression of PDX-1 dependent beta-cell specific genes. A gene switch such as the Tet-On system provides a powerful tool to analyze eukaryotic gene expression and function in transgenic mice. The original Tet system contained two transcriptional units, transactivator and target of control, on two plasmids. We combined the two transcriptional units on a single DNA molecule. The transactivator was placed under control of the mouse insulin promoter. The tet responsive element, driving the gene of interest, was inserted further down-stream into the same vector. The tet regulatory system in this approach permitted a tissue-specific and a doxycycline-inducible control of PDX-1 expression in transgenic mice. The expression of glucose transporter 2 and glucokinase was markedly reduced in dox-treated transgenic mice. In contrast, the number of insulin- and amylin-expressing cells was only slightly decreased, whereas the expression of glucagon was increased distinctly in islets of these mice. Furthermore, the exposure to doxycycline resulted in a progressive impairment of glucose tolerance. The characterization of our transgenic mouse model demonstrates the suitability of the Tet-On system for analyzing physiological consequences emerging from a stepwise decrease in a given protein. Using this system we confirmed the essential role of PDX-1 in pancreatic islets and demonstrated that an antisense-mediated PDX-1 deficiency provokes a beta-cell dysfunction.

Clinical management of psoriasis: principles and practice

A chronic condition that compromises many patients' quality of life, psoriasis is treatable with a range of agents, either alone or in combination. Clinical management strategies using these therapies can be organized as a stepped-care approach. For mild disease, corticosteroids and other topical therapies (step 1) are often appropriate. When lesions are more pronounced or extensive, phototherapy (step 2) is often the treatment of choice, and topical treatments or the step 3 agent acitretin can be added to enhance or accelerate therapeutic responses. Step 3 agents, which also include cyclosporine and methotrexate, may be contemplated when psoriasis is moderate or severe. Acitretin may cause acute adverse effects, including mucocutaneous effects, which can be avoided by reducing dosage. Methotrexate treatment can lead to bone marrow suppression and hepatotoxicity, and cyclosporine can cause nephrotoxicity. The clinical uses of these agents are illustrated in part through case presentations drawn from the authors' practices, and the supportive role of the National Psoriasis Foundation is reviewed.

Regulation of glucose-6-phosphatase gene expression by protein kinase Balpha and the forkhead transcription factor FKHR. Evidence for insulin response unit-dependent and -independent effects of insulin on promoter activity

Glucose-6-phosphatase plays an important role in the regulation of hepatic glucose production, and insulin suppresses glucose-6-phosphatase gene expression. Recent studies indicate that protein kinase B and Forkhead proteins contribute to insulin-regulated gene expression in the liver. Here, we examined the role of protein kinase B and Forkhead proteins in mediating effects of insulin on glucose-6-phosphatase promoter activity. Transient transfection studies with reporter gene constructs demonstrate that insulin suppresses both basal and dexamethasone/cAMP-induced activity of the glucose-6-phosphatase promoter in H4IIE hepatoma cells. Both effects are partially mimicked by coexpression of protein kinase Balpha. Coexpression of the Forkhead transcription factor FKHR stimulates the glucose-6-phosphatase promoter activity via interaction with an insulin response unit (IRU), and this activation is suppressed by protein kinase B. Coexpression of a mutated form of FKHR that cannot be phosphorylated by protein kinase B abolishes the regulation of the glucose-6-phosphatase promoter by protein kinase B and disrupts the ability of insulin to regulate the glucose-6-phosphatase promoter via the IRU. Mutation of the insulin response unit of the glucose-6-phosphatase promoter also prevents the regulation of promoter activity by FKHR and protein kinase B but only partially impairs the ability of insulin to suppress both basal and dexamethasone/cAMP-stimulated promoter function. Taken together, these results indicate that signaling by protein kinase B to Forkhead proteins can account for the ability of insulin to regulate glucose-6-phosphatase promoter activity via the IRU and that other mechanisms that are independent of the IRU, protein kinase B, and Forkhead proteins also are important in mediating effects of in insulin on glucose-6-phosphatase gene expression.

Some fly sensory organs are gliogenic and require glide/gcm in a precursor that divides symmetrically and produces glial cells

In flies, the choice between neuronal and glial fates depends on the asymmetric division of multipotent precursors, the neuroglioblast of the central nervous system and the IIb precursor of the sensory organ lineage. In the central nervous system, the choice between the two fates requires asymmetric distribution of the glial cell deficient/glial cell missing (glide/gcm) RNA in the neuroglioblast. Preferential accumulation of the transcript in one of the daughter cells results in the activation of the glial fate in that cell, which becomes a glial precursor. Here we show that glide/gcm is necessary to induce glial differentiation in the peripheral nervous system. We also present evidence that glide/gcm RNA is not necessary to induce the fate choice in the peripheral multipotent precursor. Indeed, glide/gcm RNA and protein are first detected in one daughter of IIb but not in IIb itself. Thus, glide/gcm is required in both central and peripheral glial cells, but its regulation is context dependent. Strikingly, we have found that only subsets of sensory organs are gliogenic and express glide/gcm. The ability to produce glial cells depends on fixed, lineage related, cues and not on stochastic decisions. Finally, we show that after glide/gcm expression has ceased, the IIb daughter migrates and divides symmetrically to produce several mature glial cells. Thus, the glide/gcm-expressing cell, also called the fifth cell of the sensory organ, is indeed a glial precursor. This is the first reported case of symmetric division in the sensory organ lineage. These data indicate that the organization of the fly peripheral nervous system is more complex than previously thought.

Apolipoprotein E4 promotes the early deposition of Abeta42 and then Abeta40 in the elderly

The apolipoprotein Eepsilon4 allele (ApoEepsilon4) is associated with a selective increase in deposition of the 40-amino acid form of the beta-amyloid peptide (Abeta40) in endstage Alzheimer's disease. To determine how apoE genotype affects the early events in beta-amyloid pathogenesis, we analyzed the medial temporal lobes of 244 elderly persons who were not clinically demented using antibodies selective for the C termini of Abeta40 and Abeta42. We found that: (1) the number of both Abeta42- and Abeta40-positive senile plaques increase with age; (2) Abeta42 appears at younger ages, and in more amyloid deposits, than does Abeta40 in all ApoE groups; (3) when compared at similar ages, older persons with ApoEepsilon4 are more likely to have Abeta42- and Abeta40-immunoreactive deposits than are persons without ApoEepsilon4; (4) Abeta40-containing plaques arise at least a decade later than do Abeta42 plaques, and are seldom found in the medial temporal lobe of older persons lacking ApoEepsilon4; and (5) in the absence of overt Alzheimer's disease, cerebral amyloid angiopathy is rare in the elderly, but in our sample was significantly augmented in ApoEepsilon4 homozygotes. We conclude that ApoEepsilon4 hastens the onset of Abeta42 deposition in the senescent brain, which in turn fosters the earlier evolution of fibrillar, Abeta40-positive plaques, thereby increasing the risk of Alzheimer's disease.

The homeodomain of Nkx2.2 carries two cooperatively acting nuclear localization signals

NK-2 family members of homeodomain proteins have been identified as important regulators of growth and development in the ventral forebrain, heart, lung, and thyroid. In addition, Nk2.2 expression has been detected in the pancreas, where it is vital for the final differentiation of beta-cells. In our present paper, we have analyzed the domains necessary for nuclear transport of Nkx2.2. With the help of deletion mutants we identified two separate nuclear localization signals (NLS). Interestingly, both NLSs are situated in the homeodomain. They belong to the monopartite class of NLS; the proximal NLS has the sequence KKRKRR and lies at the very N-terminus of the homeodomain, while the more distal NLS RYKMKRAR is at the homeodomain C-terminus. Each NLS per se is sufficient for nuclear transport of Nkx2.2 into the nucleus, although inefficiently. Both identified NLSs act cooperatively in mediating complete nuclear transport of Nkx2.2.

Selective binding of steroid hormone receptors to octamer transcription factors determines transcriptional synergism at the mouse mammary tumor virus promoter

Transcriptional synergism between glucocorticoid receptor (GR) and octamer transcription factors 1 and 2 (Oct-1 and Oct-2) in the induction of mouse mammary tumor virus (MMTV) transcription has been proposed to be mediated through directed recruitment of the octamer factors to their binding sites in the viral long terminal repeat. This recruitment correlates with direct binding between the GR DNA binding domain and the POU domain of the octamer factors. In present study, in vitro experiments identified several nuclear hormone receptors to have the potential to bind to the POU domains of Oct-1 and Oct-2 through their DNA binding domains, suggesting that POU domain binding may be a property shared by many nuclear hormone receptors. However, physiologically relevant binding to the POU domain appeared to be a property restricted to only a few nuclear receptors as only GR, progesterone receptor (PR), and androgen receptor (AR), were found to interact physically and functionally with Oct-1 and Oct-2 in transfected cells. Thus GR, PR, and AR efficiently promoted the recruitment of Oct-2 to adjacent octamer motifs in the cell, whereas mineralocorticoid receptor (MR), estrogen receptor alpha, and retinoid X receptor failed to facilitate octamer factor DNA binding. For MMTV, although GR and MR both induced transcription efficiently, mutation of the promoter proximal octamer motifs strongly decreased GR-induced transcription without affecting the total level of reporter gene activity in response to MR. These results suggest that the configuration of the hormone response element within the MMTV long terminal repeat may promote a dependence for the glucocorticoid response upon the recruitment of octamer transcription factors to their response elements within the viral promoter.

Glycodelin mRNA is expressed in the genital tract of male and female rats (Rattus norvegicus)

In the present study we demonstrate for the first time the expression of glycodelin mRNA in the female and male genital tracts of rats using non-radioactive in situ hybridisation. Glycodelin fragment 1 (+41 to +141) shares 100% homology with the human gene sequence. In the ovary, glycodelin mRNA was restricted to granulosa cells. In the uterus, glycodelin mRNA was expressed in all epithelial cells of the endometrium. In the male reproductive tract, glycodelin mRNA was distributed in all epithelial cells of the epididymis, the prostate and the seminal vesicle. However, in the testis, glycodelin mRNA was predominantly found in spermatogonia and in spermatocytes of the seminiferous epithelium. The expression in several reproductive organs of rats offers an excellent tool to study further the physiological role of glycodelin, which is so far thought to act as an immunosuppressive factor.

The nuclear localization signal (NLS) of PDX-1 is part of the homeodomain and represents a novel type of NLS

The beta-cell homeodomain transcription factor PDX-1 has vital functions both in controlling the expression of pancreatic polypeptide hormones and in the development of the pancreas. The transactivating and DNA-binding properties of PDX-1 have been well characterized, but nuclear transport is still undefined. Here we show that PDX-1 bears a nuclear localization signal (NLS) that is part of helix 3 of the homeodomain. PDX-1 deletion mutants were tagged with enhanced green fluorescent protein (EGFP) and expressed in COS-7 cells. Subcellular localization of the respective PDX-1-EGFP fusion proteins was analyzed by direct fluorescence microscopy and Western immunoblotting using an anti-(GFP). As a result we were able to demonstrate that the homeodomain or helix 3 alone was sufficient and necessary for transport into the nucleus. Point mutations of basic amino acid residues within helix 3 led to identification of an NLS with six amino acids being crucial for nuclear transport of PDX-1. Because this NLS does not match known examples of NLSs, the PDX-1 NLS may represent a novel class of NLS.

[Cell count and differential cell count in goat milk--variability and influencing factors]

In a total of 413 dairy goats of different breeds from five herds (milk performance 550-1000 kg) somatic cell counts and cell types were investigated in fore milk samples from udder halves, in composed udder and bulk milk samples. Cytoplasmatic particles in the milk were not counted. Three herds were investigated monthly during two years. At every sampling a clinical examination of the mammary gland (fore milk, teats, gland tissue, lymphatic nodes of the udders) and a bacteriological examination of the milk samples were carried out. In all herds the clinical health status of the udders was good. Independent of the sample type the mean SCC was about 1000 x 10(3)/ml with a wide range between several millions and < 100,000/ml. A seasonal influence on the monthly minima and maxima of the bulk milk SCC was evident, the lower SCC being recorded mainly during April to October. Increasing lactation numbers and months are connected with increasing SCC. Goats with high milk SCC at the begin of the lactation tended to maintain their high SCC levels as the lactation progressed. Limit values for SCC in goat milk should take into account the influence of the kidding season of the herds upon the dynamics of the bulk milk SCC. Polymorphonuclear leukocytes were the main cell type in goat milk (around 40%), their number tended to increase as total SCC increased, in particular in samples with cell counts above one million. Likewise, the differences between SCC in the milk of corresponding udder halves increased significantly as one of the halves showed more than one million somatic cells. Defining limit values for SCC in goat milk this should be taken into account.

Identification of a cAMP response element within the glucose- 6-phosphatase hydrolytic subunit gene promoter which is involved in the transcriptional regulation by cAMP and glucocorticoids in H4IIE hepatoma cells

The expression of a luciferase reporter gene under the control of the human glucose 6-phosphatase gene promoter was stimulated by both dexamethasone and dibutyryl cAMP in H4IIE hepatoma cells. A cis-active element located between nucleotides -161 and -152 in the glucose 6-phosphatase gene promoter was identified and found to be necessary for both basal reporter-gene expression and induction of expression by both dibutyryl cAMP and dexamethasone. Nucleotides -161 to -152 were functionally replaced by the consensus sequence for a cAMP response element. An antibody against the cAMP response element-binding protein caused a supershift in gel-electrophoretic-mobility-shift assays using an oligonucleotide probe representing the glucose 6-phosphatase gene promoter from nucleotides -161 to -152. These results strongly indicate that in H4IIE cells the glucose 6-phosphatase gene-promoter sequence from -161 to -152 is a cAMP response element which is important for the regulation of transcription of the glucose 6-phosphatase gene by both cAMP and glucocorticoids.

Glucose induces glucose 6-phosphatase hydrolytic subunit gene transcription in an insulinoma cell line (INS-1)

Primer extension analysis and RNase protection assays revealed the identity of glucose 6-phosphatase gene transcripts in both the insulinoma cell line INS-1 and hepatic cells. In transient transfection assays of INS-1 cells, using constructs between the human glucose 6-phosphatase gene promoter and a luciferase reporter gene, the reporter gene activity was induced by dexamethasone and dibutyryl cAMP. Furthermore, the promoter was regulated by the glucose concentration in the medium. This effect was dependent on glucose metabolism. The data indicated that glucose 6-phosphatase gene transcription is regulated in a similar way in the insulinoma cell line and in liver.

Apolipoprotein E4 promotes incipient Alzheimer pathology in the elderly

To evaluate the influence of the apolipoprotein E (ApoE) epsilon4 allele on the age at which Alzheimer-like lesions appear in the brain, we analyzed the degree of cerebral beta-amyloidosis and neurofibrillary tangle formation in the hippocampal formation and adjacent cortical areas 28, 27, and 36 of persons who had died between the ages of 50 and 93 years and who had shown no signs of clinical dementia. The occurrence of the three common polymorphisms of the ApoE gene in this sample of 147 routine autopsy cases from eastern Germany was comparable to previously reported values in European and North American populations: ApoEepsilon2/2, 0.7%; ApoEepsilon2/3, 14.3%; ApoEepsilon2/4, 4.1%; ApoEepsilon3/3, 56.5%; ApoEepsilon3/4, 22.4%; and ApoEepsilon4/4, 2.0%. Nondemented persons carrying the ApoEepsilon4 allele were significantly more likely to have senile plaques, diffuse amyloid deposits, cerebrovascular amyloid, and neurofibrillary tangles than were those lacking E4. Comparing the two largest ApoE subgroups, ApoEepsilon3/3 and ApoEepsilon3/4, the relative increase in the occurrence of beta-amyloid in the epsilon3/4 group was evident by the mid-60s, with the relative increase in neurofibrillary tangles in this group emerging slightly earlier. The ApoEepsilon2 allele appears to delay the appearance of the lesions somewhat. We conclude that ApoEepsilon4 promotes the early appearance of beta-amyloid and neurofibrillary tangles in the elderly and that the increased frequency of these lesions is related to the higher risk of Alzheimer disease in persons bearing the ApoEepsilon4 allele.

The apolipoprotein E and beta-fibrinogen G/A-455 gene polymorphisms are associated with ischemic stroke involving large-vessel disease

The relationship between the apolipoprotein E (apoE) and beta-fibrinogen G/A-455 polymorphisms and cerebrovascular disease (CVD) was examined in the present study. We compared 227 patients with the subtypes of CVD (large-vessel disease, lacunar stroke, cardiac embolism, or undetermined pathomechanisms) with 225 control subjects. The occurrence of apoE isoforms (E2, E3, and E4) and the beta-fibrinogen G/A-455 genotype was determined in these individuals. No differences in apoE polymorphisms or allele frequencies between the CVD patients and control subjects were found. However, analysis of apoE genotypes as a function of stroke subtype revealed that the apoE4 allele was significantly more common in those patients with macroangiopathy-associated CVD. The only CVD risk factor that distinguished patients with the E4 allele from those with other apoE genotypes was elevated cholesterol. No association between the beta-fibrinogen G/A-455 polymorphism and CVD was found. However, homozygosity for the A allele was more common in patients with CVD resulting from large-vessel disease. These data demonstrate that the apoE4 allele and the AA genotype of the beta-fibrinogen G/A-455 polymorphism occur significantly more frequently in patients with CVD resulting from stenosis of large, brain-supplying vessels. Such genetic analyses may further our understanding of the etiology of cerebrovascular disease.