Biomedical subjects

M Fountoulakis

Publications and source records attributed to M Fountoulakis.

At least 37 records · Page 2Linked to original sources

PubMed2001

Changes of voltage-dependent anion-selective channel proteins VDAC1 and VDAC2 brain levels in patients with Alzheimer's disease and Down syndrome.

Voltage-dependent anion-selective channel proteins (VDACs) are pore-forming proteins found in the other mitochondrial membrane of all eukaryotes and in brain postsynaptic membranes. VDACs regulate anion fluxes of a series of metabolites including ATP, thus regulating mitochondrial metabolic functions. We determined protein levels of VDACs in individual post-mortem brain regions of patients with Down Syndrome (DS) and Alzheimer's disease (AD) using two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-mass spectroscopy (MALDI-MS). VDAC1 (SWISS-PROT accession number P21796) and VDAC2 (P45880) were unambiguously identified and quantified, but VDAC3 was not found. The spots representing VDAC1 were separated with different p/s (p/7.5, 8.5, and 10.0) probably caused by post-translational modifications as, e.g., phosphorylation. In DS cerebellum, total VDAC1 protein was elevated significantly whereas VDAC2 did not show any significant alterations. In AD brains, VDAC1 p/10.0 was significantly reduced in temporal, frontal, and occipital cortex with the p/7.5 form elevated in occipital cortex. Total VDAC1 was significantly decreased in frontal cortex and thalamus. VDAC2 was significantly elevated in temporal cortex only. The biological meaning of our results may be derangement of voltage-dependent anion-selective channel function and reflecting impaired glucose, energy, and intermediary metabolism as well as apoptotic mechanisms.

Age Factors↗

PubMed2001

Effect of strong detergents and chaotropes on the detection of proteins in two-dimensional gels.

The solubilization of a particular protein is mandatory for its subsequent resolution and detection in two-dimensional gels. However, the extraction solutions, that are compatible with the first-dimensional separation step, such as urea and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), do not solubilize all proteins in a sample. We studied the effect of various common, strong detergents and chaotropes, widely used as solubilizing agents, such as sodium dodecyl sulfate, lithium dodecyl sulfate and guanidine hydrochloride, on the solubilization of the total and membrane proteins of the bacterium Haemophilus influenzae. The proteins solubilized with each system were analyzed by two-dimensional electrophoresis and these of interest were identified by matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS). Use of sodium dodecyl sulfate, lithium dodecyl sulfate or guanidine hydrochloride for the solubilization of total proteins of the microorganism resulted in the detection of several additional spots, representing mainly outer membrane proteins, in comparison with those detected in the soluble protein fraction. Solubilization of the proteins of the cell envelope fraction with sodium dodecyl sulfate did not result in a more efficient protein detection when compared to the extraction with the urea/CHAPS system. When the dry immobilized pH gradient strips were rehydrated in a solution containing the proteins of the membrane fraction solubilized with sodium dodecyl sulfate or lithium dodecyl sulfate, a larger number of protein spots were detected in comparison with strips that were rehydrated in the urea/CHAPS solution. However, no improvement was observed in comparison with protein application in sample cups. The additional proteins detected with the use of strong detergents and chaotropes are in the majority difficult to solubilize and less hydrophobic proteins.

Bacterial Proteins↗

PubMed2001

Two-dimensional database of mouse liver proteins. An update.

We updated the two-dimensional protein database for mouse liver. Microsomal and cytosolic fractions of the liver proteins from male mice were separated by two-dimensional electrophoresis. The proteins were identified by Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) on the basis of peptide mass fingerprinting, following in-gel digestion with trypsin and matching with the theoretical peptide masses of all known proteins from all species. Approximately 5800 spots, excised from 14 two-dimensional gels, were analyzed which resulted in the identification of about 2500 proteins that were the products of 328 different genes. The database includes 112 newly identified gene products. The fractionation prior to two-dimensional electrophoresis was essential for the detection of the new proteins, 55% of which were found in the microsomal and 35% in the cytosolic fraction. The more frequently identified proteins in the various gels were heat shock proteins, house-keeping enzymes, such as ATP synthase chains, disulfide isomerase, and structural proteins, such as tropomyosin. About 45% of the identified proteins were detected 1-3 times, 45% 4-9 times, and the rest 10 or more times. Most proteins were represented by many spots. In average, about 18-20 spots were detected per gene product.

Animals↗

PubMed2001

Changes in the brain protein levels following administration of kainic acid.

Kainic acid (KA), a potent neurotoxin and excitatory amino acid, leads to derangements and modulation of brain proteins. No global brain protein expression pattern induced by KA-treatment has been reported yet. We therefore studied the effect of systemic KA administration on the levels of brain proteins. Rats were injected placebo or KA intraperitoneally and brain was taken after one week. The mitochondrial and cytosolic fractions of the brain proteins were analyzed by proteomics technologies and the levels of selected proteins were quantified using specific software. Heat shock protein HSP 27 was exclusively detected in brains of animals treated with KA, whereas the glucose regulated protein GRP 78 was downregulated. The levels of neurofilaments and alpha-internexin were significantly decreased and a fragment of tubulin alpha-1 chain was manifold increased in KA-brains. The mitochondrial enzymes dihydrolipoamide dehydrogenase, ATP synthase beta chain and isocitrate dehydrogenase were reduced and pyruvate kinase M1 was increased following KA treatment. We conclude that the concomitant determination of the brain proteins indicates altered regulation of heat shock proteins, neuronal death, cytoskeletal disruption, and mitochondrial derangement by systemic KA administration. This report confirms and extends previous studies on the effect of KA on the expression of brain proteins and suggests that our analytical system can serve as a model for neurotoxicological, neurobiological, and neuropathological proteome studies.

Animals↗

PubMed2001

Mechanism-related changes in the gene transcription and protein synthesis patterns of Haemophilus influenzae after treatment with transcriptional and translational inhibitors.

High-resolution two-dimensional gel electrophoresis of pulse-labeled Haemophilus influenzae extracts allows for the separation and quantification of more than five hundred protein spots. We have determined the changes in the protein synthesis patterns triggered by treatment with inhibitors of transcription, Rifampicin (Rif) and translation, Chloramphenicol (Chl), Erythromycin (Ery), Fusidate (Fus), Puromycin (Pur), Kanamycin (Kan), Streptomycin (Str), and Tetracycline (Tet) relative to the total protein synthesis rate. More than 200 spots changed in intensity under at least one condition. With the exception of the aminoglycosides, Kan and Str, all inhibitors triggered a clear increase in the synthesis rates of ribosomal proteins and RNA polymerase subunits. Northern analysis of rpoA, rpoB, rpoC, and six ribosomal protein genes indicated induction of transcription as well as antitermination as part of the mechanism of the regulation of gene expression. Total RNA synthesis was increased after exposure to Chl, Ery, Fus, and Tet, whereas Str had no effect. Rif led to an almost complete shutdown of RNA synthesis. Exposure to Chl, Ery, Fus, Rif, and Tet resulted in a decrease in the concentration of the stringent factor, guanosine 5',3'-bis-diphosphate (ppGpp) whereas Str again had no effect. Thus, as in Escherichia coli, the response of H. influenzae to translational inhibitors appears to be mediated by the regulatory nucleotide ppGpp.

Bacterial Proteins↗

PubMed2001

Postmortem changes in the level of brain proteins.

A systematic study on postmortem changes of brain proteins has not been performed so far and information is limited to basic principles of specific or nonspecific proteolysis or proteolysis of individual proteins. We studied protein level alterations in rat brain of animals kept at 23 degrees C for several postmortem times up to 72 h. Brain tissue protein extracts were analyzed by two-dimensional electrophoresis and the proteins with different levels were identified by matrix-assisted laser desorption ionization mass spectrometry. The changes observed mainly concerned structural proteins and enzymes. The levels of dihydropyrimidinase-related protein-2 decreased within 6 h and two new spots were detected representing shorter forms of the protein. Most of the other alterations appeared about 48 h postmortem. The most significant were reduced levels of neurofilament, alpha-internexin, synaptosomal-associated protein 25, glial fibrillary acidic protein, heat shock proteins, and dynamin-1; increased levels of 14-3-3 proteins and spectrin; and generation of shorter forms of certain proteins, such as tubulins, actin, and serum albumin. The results may be useful in neuropathology and brain protein studies.

Animals↗

PubMed2001

Selective upregulation of the ubiquitin-proteasome proteolytic pathway proteins, proteasome zeta chain and isopeptidase T in fetal Down syndrome.

The ubiquitin-proteasome proteolytic pathway is involved in an important non-lysosomal proteolytic pathway that is responsible for the highly selective turnover of cellular proteins both under basal metabolic conditions as well as stress. Protein degradation by this pathway is attributed to the 20S proteasome that forms the catalytic core of the complex. Recently there has been increasing interest in the proteasome because of its possible role in neuron degeneration and death. Fetal Down syndrome (DS) neurons were demonstrated to degenerate and undergo apoptosis in vitro. We therefore investigated the expression of different proteins involved in this degradative pathway, including subunits of the 20S proteasome, ubiquitinating and deubiquitinating enzymes, and regulatory subunits of the 26S proteasome in control and DS fetal brains by two-dimensional electrophoresis (2-DE). After 2-DE, approximately 389 protein spots were successfully identified by matrix-associated laser desorption ionization mass spectroscopy (MALDI-MS) and this was followed by quantification of twenty three proteins of the pathway. The results indicate that all but two proteins exhibited no apparent alterations in their pattern of expression. Proteasome zeta chain, an alpha subunit of the 20S proteasome (P < 0.05) and ubiquitin carboxy-terminal hydrolase T (Isopeptidase T), a deubiquitinating enzyme (P < 0.001) were significantly increased in fetal DS compared to controls. Whilst the expression of proteasome iota (n = 9, r = -0.9489, P = 0.0004) and proteasome epsilon (n = 9, r = -0.7227, P = 0.0311) chains was decreased with age in fetal DS brain, no significant correlation was obtained in the other proteins with age. The data suggest that such selective upregulation may have relevance to the developmental abnormalities that characterize this disorder.

Brain↗

PubMed2001

Unaltered expression of Fas (CD95/APO-1), caspase-3, Bcl-2 and annexins in brains of fetal Down syndrome: evidence against increased apoptosis.

Apoptosis is the mechanism by which cells are programmed to die under a wide range of physiological and developmental stimuli. Accumulating evidence indicates that enhanced apoptosis (programmed cell death) in Down syndrome (DS) may play a role in mental retardation and precocious neurodegeneration of the Alzheimer-type. In this regard, alteration of several apoptosis related proteins have been reported in adult DS brain. Fetal DS neurons exhibited increased reactive oxygen species leading to early apoptosis, however, expression of apoptosis related proteins in fetal DS, has never been considered. To address this issue, we investigated the expression of proteins involved in apoptosis including Fas (CD95, APO-1), caspase-3, Bcl-2 and annexins in the cerebral cortex of control and DS fetal brain by western blot and two dimensional electrophoresis. Here, we report that no detectable changes were obtained in fetal DS brain in the expression of Fas, caspase-3, Bcl-2 and Annexins (I, II, V, and VI) compared to controls. In parallel experiment, we also examined the expression of neuron specific enolase (NSE), a neuronal marker found to be decreased in adult DS brain, to see if there is any neuronal loss and no difference was observed between the two groups. Protein expression did not correlate with age. The unchanged levels of Fas, Bcl-2 and annexins together with unaltered caspase-3 expression, a predominant caspase that executes apoptosis in the developing nervous system, suggest that enhanced apoptosis may not be apparent in fetal DS brain as demonstrated for adult DS brain.

Annexins↗

PubMed2001

Increased brain protein levels of carbonyl reductase and alcohol dehydrogenase in Down syndrome and Alzheimer's disease.

Oxidative stress is considered to be crucial in the pathogenesis of Alzheimer's disease-like neurodegeneration. An elevation of carbonyl compounds that are biomarkers of and leading to oxidative stress has been demonstrated in Down Syndrome (DS) and Alzheimer's Disease (AD) brains and seems to be the result of a multifactorial process. Carbonyls, which are cytotoxic metabolic intermediates, are detoxified by either oxidation catalyzed by aldehyde dehydrogenase (ALDH), or by reduction to their corresponding alcohols by carbonyl reductase (CBR) and/or alcohol dehydrogenase (ADH). We quantified protein levels of CBR and its agonist/antagonist ADH using 2D gel electrophoresis with subsequent MALDI-identification and specific software in several brain regions of DS as well as AD patients and compared them to levels of CBR and ADH in brains of controls. Protein levels of both enzymes were increased in several brain regions because of enzyme induction by elevated carbonyls in DS and AD. Increased CBR in DS (trisomy 21) may be due to a gene dosage effect as the gene encoding CBR has been mapped to chromosome 21. These findings may confirm the proposed increase of reactive carbonyls in the brain thus supporting the involvement of oxidative stress and contribute to the understanding of carbonyl handling in brain of both neurodegenerative disorders.

Adult↗

PubMed2001

Carbohydrate handling enzymes in fetal Down syndrome brain.

Impaired glucose metabolism in adult Down Syndrome (DS) has been well-documented in vivo and information on the underlying biochemical defect i.e. aberrant glucose handling enzymes is already available. Nothing is known on carbohydrate handling, however, in early life of DS patients, when no secondary phenomena as e.g. Alzheimer-like neuropathology occur in the brain yet. We therefore determined a series of key enzymes of carbohydrate metabolism in fetal control and DS brain during the early second trimenon. We used two-dimensional electrophoresis with subsequent MALDI characterization and specific software for quantification of protein spots. We observed comparable levels of phosphoglycerate mutase, phosphoglycerate kinase 1; fructose-biphosphate aldolase A, fructose bisphosphate aldolase C; ribose-phosphate pyrophosphokinase 1; D-phosphoglycerate dehydrogenase, 6-phosphogluconolactonase; aflatoxin B1 aldehyde reductase 1, aldose reductase; inosine-5'-monophosphate dehydrogenase 2; galactokinase, in brain of fetal controls and DS. We conclude that our biochemical findings point to the fact that DS patients start early life with unchanged glucose handling, pentose phosphate shunt, glycolysis, sugar aldehyde, guanine nucleotide- and ribonucleoside formation and galactose metabolism.

Brain↗

PubMed2001

Protein levels of human peroxiredoxin subtypes in brains of patients with Alzheimer's disease and Down syndrome.

Human peroxiredoxin (Prx) play important roles in eliminating hydrogen peroxide generated during cellular mechanisms using electrons from thioredoxin (Trx). Oxidative stress induced by reactive oxygen species (ROS) such as hydrogen peroxide has been implicated in the pathogenesis of several neurodegenerative diseases. We applied the proteomic approach to study protein levels of three subtypes of human Prx in brain regions from patients with Alzheimer's disease (AD) and Down Syndrome (DS). Protein levels of Prx-I and Prx-II were significantly increased in AD and DS. Protein levels of Prx-III, a mitochondrial protein, however, were significantly decreased. We conclude that increased protein levels of Prx-I and Prx-II could provide protection against neuronal cell death induced by hydrogen peroxide. Decreased protein levels of Prx-III could be caused by mitochondrial damage shown in AD and DS. Showing upregulated Prx protein levels provides evidence for the involvement of ROS in the pathogenesis of AD and DS.

Aged↗

PubMed2001

Increased protein levels of heterogeneous nuclear ribonucleoprotein A2/B1 in fetal Down syndrome brains.

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are predominantly nuclear RNA-binding proteins that form complexes with RNA polymerase II transcripts. These proteins play pivotal roles in transcription, pre-mRNA processing in the nucleus, cytoplasmic mRNA translation and its turnover. In addition, hnRNPs have been shown to be essential for embryonic development of Drosophila. Here we studied the protein levels of hnRNPs (A2/B1, H and H') in fetal brain with Down syndrome (DS; n = 5) compared to controls (n = 7). We used two-dimensional (2-D) gel electrophoresis, matrix-assisted laser desorption ionization mass spectroscopy (MALDI-MS) and specific software for quantification. hnRNP A2/B1 was significantly increased in fetal DS brain (13.52+/-4.50) compared to controls (9.16+/-1.35), but both hnRNP H and H' were unchanged. Increased hnRNP A2/B1 in fetal DS brain may represent high activity of RNA processing such as RNA trafficking and telomere protection, and/or it could contribute to abnormal development of DS brains. Furthermore, comparable expression of hnRNP H and H' suggest a specific upregulation of hnRNP A2/B.

Brain↗

PubMed2001

Decreased protein levels of stathmin in adult brains with Down syndrome and Alzheimer's disease.

Stathmin, distributed in neurons with high abundance, acts as an intracellular relay, integrating various transduction pathways triggered by extracellular signals and it is involved in physiological regulation of microtubule destabilization. Stathmin has been also shown to be a critical molecule in pathology of neurodegeneration such as Alzheimer's disease (AD), particularly, in neurofibrillary tangle (NFT) formation. Here we evaluated protein levels of stathmin in adult brain from patients with AD and Down syndrome (DS) showing AD-like pathology by applying proteomic technologies with two-dimensional (2-D) gel electrophoresis, matrix-assisted laser desorption ionization mass spectroscopy (MALDI-MS) identification and specific software for quantification of proteins. Significantly decreased protein levels of stathmin were observed in frontal (2.12+/-1.17, n = 6) and temporal (3.05+/-2.81, n = 10) cortices of AD compared to controls (frontal cortex: 4.41+/-1.70, n = 8; temporal cortex: 5.26+/-2.26, n = 13). Stathmin was also significantly decreased in frontal (2.47+/-1.11, n = 7) and temporal (2.02+/-1.18, n = 9) cortices of DS. We also investigated stathmin levels in fetal brain. Stathmin was not significantly changed between fetal DS brain and controls. We suggest that the decreased protein level of stathmin in brains is associated with tangle formation and microtubule instability in DS as well as AD, but stathmin is not involved in the abnormal development of fetal DS brain.

Adult↗

PubMed2001

Expression profiles of proteins in fetal brain with Down syndrome.

Proteomics is a powerful tool for evaluating differential protein expression comparing hundreds of proteins simultaneously. In the current study we performed "gene hunting" at the protein level and identified and quantified 10 protein spots in control and Down syndrome (DS) fetal brains. Using two-dimensional (2-D) electrophoresis of fetal brain proteins with subsequent MALDI-identification and quantification with specific software, we identified a series of poorly known proteins, in part hypothetical and orphans or poorly documented proteins. Hypothetical protein DKFZp564D177.1-human (fragment), one of these proteins was identified in fetal brain and was significantly decreased in DS (0.61+/-0.44, n = 7) compared to controls (3.43+/-1.83, n = 7). Septin 6, previously shown to be associated with synaptic vesicles, was present in all of 7 controls, but only in 1 out of 6 DS brains. We suggest that decreased protein levels of hypothetical protein DKFZp564D177.1-human (fragment) and lower prevalence of septin 6 could be involved in the maldevelopment of fetal DS brains. The other 8 proteins (WD repeat protein 1, novel protein highly similar to septin 2 homolog, septin 5, septin 2, DJ37E16.5 (novel protein similar to nitrophenylphosphatases from various organism), hypothetical 30.2 kDa protein, neuronal protein NP25, and DC7 protein (vacuolar sorting protein 29)) were comparable between controls and DS but could be identified in fetal and DS cortex, thus proposing them as tentative brain proteins.

Brain↗

PubMed2001

Expression patterns of chaperone proteins in cerebral cortex of the fetus with Down syndrome: dysregulation of T-complex protein 1.

Chaperone proteins reduce stress-induced denaturation and aggregation of intracellular proteins and exert protective actions by interfering with the stress-induced apoptotic pathway in the neuronal cells. Although many studies have focused on the critical role of chaperones in protein folding and their relevance in protein conformational diseases such as Alzheimer's disease (AD) and prion disease, limited information is available on their expression pattern in AD-related disease, Down Syndrome (DS). In a previous study, we reported differentially expressed molecular chaperone proteins in the brains of adult DS patients. This report demonstrated the relevance of the aberrant expression patterns to biochemical and neuropathological abnormalities in adult DS brain. To investigate whether this aberrant expression patterns already exist in second trimester DS brain, we performed two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-associated laser desorption ionization mass spectroscopy (MALDI-MS) using fetal DS brain. We unambiguously identified and quantified twelve heat shock proteins (HSPs), three glucose regulated proteins (GRPs) and eight T-complex 1 (TCP-1) subunits. Unlike in adult brain with DS, these studies provide evidence for the normal response of most molecular chaperone proteins at the given time point of DS brain development. However, chaperonin protein TCP-1 alpha and beta subunits showed a significant decrease (P < 0.05) in second trimester brain with DS. Comparable response of chaperone proteins in fetal DS brain suggests that not heat-shock induced proteins but rather chaperonin protein TCP-1 may contribute significantly to neuropathogenesis in the early second trimester DS brain. This study extends observations of distinct expression patterns of molecular chaperones in DS brain and we discuss the relevance of aberrant TCP-1 expression patterns to developmental DS brain at the early stage.

Cerebral Cortex↗

PubMed2001

Beta-amyloid precursor protein, ETS-2 and collagen alpha 1 (VI) chain precursor, encoded on chromosome 21, are not overexpressed in fetal Down syndrome: further evidence against gene dosage effect.

Down syndrome (DS) is the most common human chromosomal abnormality caused by an extra copy of chromosome 21 and characterized clinically by somatic anomalies, mental retardation and precocious dementia. The phenotype of DS is thought to result from overexpression of a gene or genes located on the triplicated chromosome or chromosome region. Reports that challenge this notion, however, have been published. To add to this body of evidence, the expression of beta-amyloid precursor protein (APP), ETS-2 and collagen alpha1 (VI) chain precursor, encoded on chromosome 21, was investigated in fetal brain by western blot and two-dimensional electrophoresis (2-DE). Western blot detected APP and ETS-2 that migrated at approximately 75 and 50kDa, respectively. Subsequent densitometric analysis of APP and ETS-2 immunoreactivity did not produce any significant change between controls and DS. Since the metabolic fate of APP determines the propensity of amyloid beta production, the expression of the secreted forms of APP (sAPP) had been examined. Neither the expression of sAPPalpha nor sAPPbeta showed any detectable changes among the two groups. Collagen alpha1 (VI) chain precursor, a protein resolved as a single spot on 2D gel was identified by matrix associated laser desorption ionization mass spectroscopy. Quantitative analysis of this spot using the 2D Image Master software revealed a significant decrease in fetal DS (P < 0.01) compared to controls. Linear regression analysis did not show any correlation between protein levels and age. The current data suggest that overexpression per se can not fully explain the DS phenotype.

Amyloid beta-Protein Precursor↗

PubMed2001

Reduction of nucleoside diphosphate kinase B, Rab GDP-dissociation inhibitor beta and histidine triad nucleotide-binding protein in fetal Down syndrome brain.

Information on the various factors leading to impairments in the developing brain of fetal Down Syndrome patients is limited to few histological reports. We therefore attempted to describe expression levels of proteins in brain using the proteomic technique of two-dimensional electrophoresis with subsequent mass spectroscopical identification of protein spots and quantification with specific software. Cortical tissue was obtained from autopsy of human fetal abortus. Protein levels of GTP-binding nuclear protein ran, guanine nucleotide-binding protein g(o), alpha subunit 2, guanine nucleotide-binding protein g(i)/g(s)/g(t) beta subunit 1, -beta subunit 2, guanine nucleotide-binding protein beta subunit 5, nucleoside diphosphate kinase A, nucleoside diphosphate kinase B, Rab GDP-dissociation inhibitor beta, Rho GDP-dissociation inhibitor 1, biphosphate 3'-nucleotidase, small glutamine-rich tetra-tricopeptide repeat-containing protein and histidine triad nucleotide-binding protein were studied. Quantification revealed statistically significant reduced levels of nucleoside diphosphate kinase B, Rab GDP-dissociation inhibitor beta and histidine triad nucleotide-binding protein in fetal DS brain as compared to controls. We conclude that in early prenatal life proteins involved in neural differentiation, migration and synaptic transmission are impaired in DS cortex. These results may help to understand the abundant mechanisms leading to abnormalities in the wiring, structure and function of DS brain.

Brain↗

PubMed2001

Deterioration of the transcriptional, splicing and elongation machinery in brain of fetal Down syndrome.

Perturbation of brain development i.e. regulation of gene expression, differentiation, growth and migration in Down Syndrome (DS) has been reported to occur early in life pointing to impairment of the complex system of transcription and or translation and indeed, altered expression of transcription factors has been reported in adult DS brain. We therefore decided to compare the transcriptional and translational machinery in cortex of brains of controls and fetuses with Down syndrome in the second trimenon of gestation. We determined a series of transcription/translation factors by 2 D-electrophoresis followed by MALDI--identification and quantification with specific software. The protooncogene C-CRK, CRK-like protein, elongation factor 1-alpha 1, elongation factor 2, elongation factor tu and two out of four spots representing PTB-associated splicing factor PSF were significantly downregulated in brain of fetal DS fetuses as compared to controls. The finding of reduced transcription and translation factors may indicate deranged protein synthesis. The underlying cause for individual reduced transcription, splicing and translation factors may be explained by chromosomal imbalance or by posttranslational modifications as e.g. phosphorylation, known to be aberrant in DS. Reduced expression of transcription factors in fetal DS during early life may be responsible or reflecting impaired brain development and deficient wiring of the brain in DS.

Brain↗