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M Eggert

Publications and source records attributed to M Eggert.

At least 19 recordsLinked to original sources
PubMed2006

Spots, blots, peaks and chips: proteomic approaches in autoimmune diseases.

During the past five years, investigations employing a variety of proteomic technologies have yielded a wealth of information on a number of autoimmune disorders. Animal models of autoimmune disease have been examined and have provided clues that can be useful in elucidating molecular pathways and mechanisms that play a role in autoimmune disorders. Human sera and body fluids have been analyzed and have resulted in the identification of autoantibodies that can be used as diagnostic markers in specific autoimmune diseases, and proteomic fingerprints of tissues and body fluids have resulted in the identification of individual proteins or patterns of protein expression that are deregulated in autoimmune diseases. The information provided by these proteomic studies are of diagnostic and therapeutic potential. This review provides an overview of the approaches used in the proteomic analyses of autoimmune disease.

Animals↗
PubMed2004

Novel ligands: fine tuning the transcriptional activity of the glucocorticoid receptor.

Glucocorticoids are the first line medication used in the therapy of many severe inflammatory disorders. They exert their activity through binding to the glucocorticoid receptor, a ligand-dependent transcription factor, and result in either activation or repression of a large set of glucocorticoid responsive genes. The desired immunosuppressive effect is apparently due largely to the down-regulation of a variety of pro-inflammatory factors, whereas adverse reactions such as corticoid-induced diabetes and osteoporosis could be connected to the inappropriate activation of genes involved in the control of metabolic processes. The discovery of improved glucocorticoids, which maintain beneficial therapeutic activity together with a diminished risk of side effects, focuses on ligands that lead to repression rather than activation of genes targeted by the glucocorticoid receptor. Current drug-screening programs have yielded a number of molecules including steroidal as well as non-steroidal compounds, which preferentially induce receptor-mediated repression. The characterization of these novel glucocorticoids in several in vitro and in vivo models for their immune modulating activity marks an important step towards the development of a new class of safer glucocorticoid preparations.

Animals↗
PubMed2001

Identification of nucleolin as a glucocorticoid receptor interacting protein.

The glucocorticoid receptor (GR) is a ligand-induced transcription factor which modulates the transcriptional activity of target genes. Full transcriptional activity of GR is achieved with the help of accessory proteins that are able to interact with GR. We have identified a 95-kDa protein by a blotting technique which utilizes a radioactively labeled DNA-bound GR to detect proteins that bind to this complex. Biochemical purification of this protein followed by protein microsequencing resulted in the identification of human nucleolin. In addition we could show that a GR-deletion mutant localizes to the nucleolus, where nucleolin is one of the most abundant proteins. The binding of nucleolin to this deletion mutant was demonstrated by GST-pull-down experiments. We suggest a biological role of nucleolin in binding of GR in the nucleolus.

Animals↗
PubMed2001

Effects of the heterogeneous nuclear ribonucleoprotein U (hnRNP U/SAF-A) on glucocorticoid-dependent transcription in vivo.

The glucocorticoid receptor (GR) is a ligand dependent transcription factor, which regulates the transcription of multiple hormone-dependent genes. The transcriptional regulation by GR takes place by interaction of GR with the basal transcription machinery and by recruiting glucocorticoid receptor interacting proteins (GRIPs). Previously we identified hnRNP U/SAF-A as a factor interfering with GR-dependent transcription by repressing glucocorticoid induced activation. To gain insight into the mechanisms that govern this interference, we have now investigated the transcription of GR-dependent reporter genes in Ltk(-) cells transiently transfected with a variety of hnRNP U constructs. We demonstrate that a hnRNP U construct lacking the GR-binding domain acts as a dominant negative factor that now enhances GR-driven transcription. In addition, hnRNP U repression of glucocorticoid induced transcription was found to be dependent on the amount of cotransfected GR, where a high amount of GR leads to ligand-inducible repression of GR-dependent reporter gene activity by hnRNP U, whereas low amounts of GR showed nearly no effect. The relative concentrations of GR, hnRNP U and DNA-binding sites for GR are important for the effect of hnRNP U on transcription, suggesting a model where hnRNP-U acts as a storage site for intranuclear GR.

Binding Sites↗
PubMed2000

Distinct proteins interacting with the glucocorticoid receptor.

The glucocorticoid receptor (GR) is a hormone-dependent transcription factor that modulates gene transcription by binding to its response element, interacting with other transcription factors, contacting the basal transcription machinery and by interacting with several intermediary proteins, such as coactivators. Here we discuss the most prominent examples for interacting transcription factors, interacting proteins that belong to the basal transcription apparatus and intermediary factors. Furthermore, we describe a new class of GR-interacting proteins (GRIPs) which have been identified by a blotting technique, using a radioactively labeled GR/GRE complex as a probe to identify proteins that interact with the activated GR. Two of these GRIPs, termed GRIP170 and GRIP 120, which were identified by biochemical purification and microsequencing and have turned out to play a role in modulating GR-mediated transcription, are discussed in detail.

Animals↗
PubMed1999

Cladistic association analysis of Y chromosome effects on alcohol dependence and related personality traits.

Association between Y chromosome haplotype variation and alcohol dependence and related personality traits was investigated in a large sample of psychiatrically diagnosed Finnish males. Haplotypes were constructed for 359 individuals using alleles at eight loci (seven microsatellite loci and a nucleotide substitution in the DYZ3 alphoid satellite locus). A cladogram linking the 102 observed haplotype configurations was constructed by using parsimony with a single-step mutation model. Then, a series of contingency tables nested according to the cladogram hierarchy were used to test for association between Y haplotype and alcohol dependence. Finally, using only alcohol-dependent subjects, we tested for association between Y haplotype and personality variables postulated to define subtypes of alcoholism-antisocial personality disorder, novelty seeking, harm avoidance, and reward dependence. Significant association with alcohol dependence was observed at three Y haplotype clades, with significance levels of P = 0.002, P = 0.020, and P = 0.010. Within alcohol-dependent subjects, no relationship was revealed between Y haplotype and antisocial personality disorder, novelty seeking, harm avoidance, or reward dependence. These results demonstrate, by using a fully objective association design, that differences among Y chromosomes contribute to variation in vulnerability to alcohol dependence. However, they do not demonstrate an association between Y haplotype and the personality variables thought to underlie the subtypes of alcoholism.

Alcoholism↗
PubMed1999

Alien, a highly conserved protein with characteristics of a corepressor for members of the nuclear hormone receptor superfamily.

Some members of nuclear hormone receptors, such as the thyroid hormone receptor (TR), silence gene expression in the absence of the hormone. Corepressors, which bind to the receptor's silencing domain, are involved in this repression. Hormone binding leads to dissociation of corepressors and binding of coactivators, which in turn mediate gene activation. Here, we describe the characteristics of Alien, a novel corepressor. Alien interacts with TR only in the absence of hormone. Addition of thyroid hormone leads to dissociation of Alien from the receptor, as shown by the yeast two-hybrid system, glutathione S-transferase pull-down, and coimmunoprecipitation experiments. Reporter assays indicate that Alien increases receptor-mediated silencing and that it harbors an autonomous silencing function. Immune staining shows that Alien is localized in the cell nucleus. Alien is a highly conserved protein showing 90% identity between human and Drosophila. Drosophila Alien shows similar activities in that it interacts in a hormone-sensitive manner with TR and harbors an autonomous silencing function. Specific interaction of Alien is seen with Drosophila nuclear hormone receptors, such as the ecdysone receptor and Seven-up, the Drosophila homologue of COUP-TF1, but not with retinoic acid receptor, RXR/USP, DHR 3, DHR 38, DHR 78, or DHR 96. These properties, taken together, show that Alien has the characteristics of a corepressor. Thus, Alien represents a member of a novel class of corepressors specific for selected members of the nuclear hormone receptor superfamily.

Amino Acid Sequence↗
PubMed1998

Multiple receptor interaction domains of GRIP1 function in synergy.

Nuclear hormone receptors are exerting their effect on transcription by interacting with basal factors of the transcription machinery and/or by recruiting intermediary factors, such as the mouse protein GRIP1. GRIP1 is one of the recently identified coactivators for nuclear hormone receptors. Upon interaction with the hormone-binding domain of the receptors, GRIP1 increases their transcriptional activity. Here we show that GRIP1 contains at least two receptor-interacting regions using the hormone-binding domain of several receptors as bait in the yeast two-hybrid assay. GRIP1 interacts in a hormone-dependent manner with the C-termini of nuclear hormone receptors such as GRalpha, TRalpha, TRbeta, RARalpha and RXRalpha but not with v-ErbA. GRIP1 contains several LXXLL motifs which were shown to be required for receptor interaction. A protein fragment containing all of the three LXXLL motifs, but having the activation domain deleted, is able to repress the transcriptional activity of human TRbeta, whereas a region harbouring only one LXXLL motif fails to do so. A protein fragment with two LXXLL motifs exhibits an intermediate modulation of the TRbeta transactivation. While one motif seems to be sufficient for receptor interaction, more than one motif is needed for functional interference.

Amino Acid Sequence↗
PubMed1998

Mutation screening of the 5-hydroxytryptamine7 receptor gene among Finnish alcoholics and controls.

Impaired central serotonin neurotransmission has been associated with increased aggression, impaired impulse control and diurnal activity rhythm disturbances among humans. Neuroanatomic distribution and pharmacological properties of the serotonin 5-HT7 receptor suggest that it may play a role in psychiatric disorders and in circadian rhythm regulation. In this study a point mutation causing proline279 --> leucine amino acid substitution in the 5-hydroxytryptamine7 (5-HT7) receptor gene was discovered. This 5-HT7Leu279 variant was observed in six of 825 individuals, all of whom are heterozygous for the substitution. Three of them are alcoholic offenders (3/255), two are relatives of an offender without the 5-HT7Leu279 allele (2/255) and one is a healthy control without any psychiatric diagnosis (1/248). The allele frequency of the 5-HT7Leu279 variant is 0.004 (6/758) among Finns. Although the 5-HT7Leu279 variant is approximately three times more common among alcoholic offenders than among healthy controls, it is not significantly associated with alcoholism or impulsivity in the present study. The 5-HT7Leu279 allele may, however, be a predisposing allele in a subgroup of alcoholic offenders with multiple behavioral problems.

Adult↗
PubMed1998

Role of the serotonin transporter promoter polymorphism in anxiety-related traits.

BACKGROUND: The heritability of interindividual variation in anxiety and other aspects of personality establishes that variants of genes influence these traits. A functional polymorphism in the promoter of the human serotonin transporter gene (SLC6A4*C) was identified and found to be linked to an anxiety-related personality trait, Neuroticism. The polymorphism affects gene transcription and, ultimately, gene function. We have attempted to confirm the role of SLC6A4*C in anxiety-related personality traits by sibpair analysis and association studies. METHODS: Sibpair linkage analysis and association study were performed in 655 Finns. The index cases were 182 alcoholic criminal offenders, through which 258 relatives were ascertained to obtain 366 sibpairs. In addition, 215 unrelated population controls were collected. Each individual was psychiatrically interviewed, blind-rated for DSM-III-R diagnoses, and assessed with the Tridimensional Personality Questionnaire. RESULTS: The sibpair analysis revealed a positive linkage between SLC6A4*C and the 2 anxiety-related subdimensions of Harm Avoidance: HA1 (Anticipatory Worry) and HA2 (Fear of Uncertainty) (P = .003). However, there was no consistent association between SLC6A4*C and any Tridimensional Personality Questionnaire trait. CONCLUSIONS: In the present study we replicated the relationship of SLC6A4*C to anxiety by sibpair linkage analysis but found no evidence of association, raising the question of whether SLC6A4*C locus is itself affecting anxiety or is linked to another still unknown functional variant.

Alcoholism↗
PubMed1998

Linkage of antisocial alcoholism to the serotonin 5-HT1B receptor gene in 2 populations.

BACKGROUND: In mice, quantitative trait locus studies and behavioral evaluation of animals deleted for 5-HT1B have implicated this serotonin autoreceptor in alcohol consumption and aggressive behavior. We therefore investigated whether the 5-HT1B gene (HTR1B) is linked to alcoholism with aggressive and impulsive behavior in the human, as represented by 2 psychiatric diagnoses: antisocial personality disorder and intermittent explosive disorder comorbid with alcoholism. METHODS: Linkage was first tested in 640 Finnish subjects, including 166 alcoholic criminal offenders, 261 relatives, and 213 healthy controls. This was followed by a study in a large multigenerational family derived from a Southwestern American Indian tribe (n=418) with a high rate of alcoholism. All subjects were psychiatrically interviewed, blind-rated for psychiatric diagnoses, and typed for a HTR1B G861C polymorphism and for a closely linked short-tandem repeat locus, D6S284. Linkage was evaluated in sib pairs, and by using an association approach in which pedigree randomization corrects for nonindependence of observations on related subjects. RESULTS: In Finnish sib pairs, antisocial alcoholism showed significant evidence of linkage to HTR1B G861C (P=.04) and weak evidence with D6S284 (P=.06). By association analysis, the 183 Finnish antisocial alcoholics had a significantly higher HTR1B-861C allele frequency than the other 457 Finns we studied (P=.005). In the Southwestern American Indian tribe, significant sib pair linkage of antisocial alcoholism to HTR1B G861C (P=.01) was again observed, and there was also significant linkage to D6S284 (P=.01). CONCLUSION: These results suggest that a locus predisposing to antisocial alcoholism may be linked to HTR1B at 6q13-15.

Adolescent↗
PubMed1998

A tryptophan hydroxylase gene marker for suicidality and alcoholism.

BACKGROUND: Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the synthesis of serotonin. Low turnover rate of this monoamine neurotransmitter is associated with impaired impulse control. We previously reported that, in Finns, TPH genotype was associated with suicidality, a pathophysiological mechanism that may involve impaired impulse control. METHODS: Association and sib-pair linkage analyses of a polymorphism in intron 7 of the TPH gene with suicidality, alcoholism, and the Karolinska Scales of Personality were conducted in 804 Finnish alcoholic offenders, controls, and their relatives, in a sample that included 369 sib pairs. RESULTS: The association of the TPH 17 779C (L) allele to suicidality in impulsive offenders reported previously was replicated in a new group of Finnish offenders (P=.001, n=122). The intron 7 variant in the TPH gene showed significant evidence for linkage to suicidality (P=.006 in unaffected sib pairs), severe suicide attempts (P=.006 in unaffected sib pairs; regression: P=.01), alcoholism (P=.003 in unaffected sib-pairs; regression: P=.02), and Karolinska Scales of Personality socialization score (regression: P=.002). CONCLUSIONS: The status of the TPH A779C allele as a marker for suicidality was replicated and linkage with alcoholism and Karolinska Scales of Personality socialization score was also observed. A functional variant(s) in or close to the TPH gene may predispose individuals to suicidality and other behaviors thought to be influenced by serotonin.

Adult↗
PubMed1998

The DNA-binding and tau2 transactivation domains of the rat glucocorticoid receptor constitute a nuclear matrix-targeting signal.

Using an ATP-depletion paradigm to augment glucocorticoid receptor (GR) binding to the nuclear matrix, we have identified a minimal segment of the receptor that constitutes a nuclear matrix targeting signal (NMTS). While previous studies implicated a role for the receptor's DNA-binding domain in nuclear matrix targeting, we show here that this domain of rat GR is necessary, but not sufficient, for matrix targeting. A minimal NMTS can be generated by linking the rat GR DNA-binding domain to either its tau2 transactivation domain in its natural context, or a heterologous transactivation domain derived from the Herpes simplex virus VP16 protein. The transactivation and nuclear matrix-targeting activities of tau2 are separable, as transactivation mutants were identified that either inhibited or had no apparent effect on matrix targeting of tau2. A functional interaction between the NMTS of rat GR and the RNA-binding nuclear matrix protein hnRNP U was revealed in cotransfection experiments in which hnRNP U overexpression was found to interfere with the transactivation activity of GR derivatives that possess nuclear matrix-binding capacity. We have therefore ascribed a novel function to a steroid hormone transactivation domain that could be an important component of the mechanism used by steroid hormone receptors to regulate genes in their native configuration within the nucleus.

Adenosine Triphosphate↗
PubMed1997

The glucocorticoid receptor is associated with the RNA-binding nuclear matrix protein hnRNP U.

The glucocorticoid receptor (GR) is a ligand-dependent transcription factor that is able to modulate gene activity by binding to its response element, interacting with other transcription factors, and contacting several accessory proteins such as coactivators. Here we show that GRIP120, one of the factors we have identified to interact with the glucocorticoid receptor, is identical to the heterogeneous nuclear ribonucleoprotein U (hnRNP U), a nuclear matrix protein binding to RNA as well as to scaffold attachment regions. GR.hnRNP U complexes were identified by blotting and coimmunoprecipitation. The subnuclear distribution of GR and hnRNP U was characterized by indirect immunofluorescent labeling and confocal laser microscopy demonstrating a colocalization of both proteins. Using a nuclear transport-deficient deletion of hnRNP U, nuclear translocation was seen to be dependent on GR and dexamethasone. Transient transfections were used to identify possible interaction domains. Overexpressed hnRNP U interfered with glucocorticoid induction, and the COOH-terminal domains of both proteins were sufficient in mediating the transcriptional interference. A possible functional role for this GR binding-protein in addition to its binding to the nuclear matrix, to RNA, and to scaffold attachment regions is discussed.

Cell Nucleus↗
PubMed1996

A prospective follow-up study of alcoholic violent offenders and fire setters.

BACKGROUND: This study investigated biochemical and family variables and predictors of recidivism among forensic psychiatric patients who had committed violent offenses or set fires. METHODS: One hundred fourteen male alcoholic violent offenders and fire setters were followed up for an average of 4.5 years after release from prison. At the beginning of their incarceration, the first half of the offenders were administered clinical diagnostic interviews, whereas the latter half received the Structured Clinical Interview for DSM-III (SCID) that was blind rated. A structured family history questionnaire was administered to all available first-degree relatives of offenders. The offenders also received lumbar punctures for monoamine metabolites, an oral glucose tolerance test, and a measurement of fasting plasma cholesterol level. At the end of the follow-up, the Finnish criminal registry was searched for recidivist crimes. RESULTS: Among all offenders, low cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) concentrations were associated with a family history positive for paternal alcoholism with violence. Low plasma cholesterol concentration was associated with a family history positive for paternal alcoholism without violence. The recidivists, who committed violent offenses or set fires during the follow-up period, had low CSF 5-HIAA and 3-methoxy-4-hydroxyphenylglycol (MHPG) concentrations compared with those in nonrecidivists. Early family environments of the recidivists, compared with those of the nonrecidivists, were characterized by common paternal absence from and presence of brothers at home. CONCLUSION: Among male alcoholic violent offenders and fire setters, low CSF 5-HIAA and HVA concentrations are strongly associated with a family history positive for paternal violence and alcoholism, while low fasting plasma cholesterol concentration is associated with a family history positive for paternal alcoholism. Recidivist violent offenders and fire setters are predicted by low CSF 5-HIAA and MHPG concentrations and a developmental history positive for early paternal absence from and presence of brothers in the family of origin.

Adult↗
PubMed1996

Enhancement of nuclear receptor transcriptional signalling.

Glucocorticoids and thyroid hormones induce complex responses in about every mammalian tissue. These effects are mediated by the transcription factor function of the corresponding nuclear receptors, which in most cases achieve the observed regulatory strength in synergy with other factors. Here we describe the functional interaction of the glucocorticoid receptor (GR) with liver-specific transcription factors, the functional synergy of GR with the thyroid hormone receptor (TR), the synergizing sub-domains of the TR, and finally the direct interaction of the GR with other proteins.

Animals↗
PubMed1996

The association between the dopamine D4 receptor (D4DR) 16 amino acid repeat polymorphism and novelty seeking.

Ebstein and colleagues have recently reported a significant association between the 7-repeat allele of the dopamine D4 receptor (D4DR) 16 amino acid repeat polymorphism and the personality trait of Novelty Seeking (NS) in 124 Israeli subjects. This study, and another study conducted in the US (although with a different personality measure) that observed a similar association, have generated wide interest in the identification of the genes involved in personality variation. We have determined D4DR genotypes in two groups of Finnish subjects; 193 psychiatrically screened normal controls and 138 alcoholic offenders and assessed NS with the Tridimensional Personality Questionnaire (TPQ). In normals, we find no significant association between NS and the 7-repeat allele despite similar allele frequencies and the use of the same personality measure as Ebstein et al. The group of alcoholic offenders have significantly higher NS than normals, however we fail to replicate the previous association in this group and, in fact, find a significant association in the opposite direction as previously observed. These data suggest that D4DR may require re-evaluation as a candidate gene for personality variation.

Adult↗