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1.
Gene Ther ; 23(12): 846-856, 2016 12.
Article in English | MEDLINE | ID: mdl-27518705

ABSTRACT

Friedreich ataxia (FRDA) is a progressive neurodegenerative disease caused by deficiency of frataxin protein, with the primary sites of pathology being the large sensory neurons of the dorsal root ganglia and the cerebellum. FRDA is also often accompanied by severe cardiomyopathy and diabetes mellitus. Frataxin is important in mitochondrial iron-sulfur cluster (ISC) biogenesis and low-frataxin expression is due to a GAA repeat expansion in intron 1 of the FXN gene. FRDA cells are genomically unstable, with increased levels of reactive oxygen species and sensitivity to oxidative stress. Here we report the identification of elevated levels of DNA double strand breaks (DSBs) in FRDA patient and YG8sR FRDA mouse model fibroblasts compared to normal fibroblasts. Using lentivirus FXN gene delivery to FRDA patient and YG8sR cells, we obtained long-term overexpression of FXN mRNA and frataxin protein levels with reduced DSB levels towards normal. Furthermore, γ-irradiation of FRDA patient and YG8sR cells revealed impaired DSB repair that was recovered on FXN gene transfer. This suggests that frataxin may be involved in DSB repair, either directly by an unknown mechanism, or indirectly via ISC biogenesis for DNA repair enzymes, which may be essential for the prevention of neurodegeneration.


Subject(s)
Friedreich Ataxia/therapy , Genetic Therapy , Genomic Instability , Iron-Binding Proteins/genetics , Animals , Cells, Cultured , DNA Breaks, Double-Stranded , Fibroblasts/metabolism , Humans , Iron-Binding Proteins/metabolism , Lentivirus/genetics , Mice , Recombinational DNA Repair , Frataxin
2.
Cell Death Dis ; 7: e2237, 2016 05 26.
Article in English | MEDLINE | ID: mdl-27228352

ABSTRACT

Friedreich's ataxia (FRDA) is an inherited neurodegenerative disease. The mutation consists of a GAA repeat expansion within the FXN gene, which downregulates frataxin, leading to abnormal mitochondrial iron accumulation, which may in turn cause changes in mitochondrial function. Although, many studies of FRDA patients and mouse models have been conducted in the past two decades, the role of frataxin in mitochondrial pathophysiology remains elusive. Are the mitochondrial abnormalities only a side effect of the increased accumulation of reactive iron, generating oxidative stress? Or does the progressive lack of iron-sulphur clusters (ISCs), induced by reduced frataxin, cause an inhibition of the electron transport chain complexes (CI, II and III) leading to reactive oxygen species escaping from oxidative phosphorylation reactions? To answer these crucial questions, we have characterised the mitochondrial pathophysiology of a group of disease-relevant and readily accessible neurons, cerebellar granule cells, from a validated FRDA mouse model. By using live cell imaging and biochemical techniques we were able to demonstrate that mitochondria are deregulated in neurons from the YG8R FRDA mouse model, causing a decrease in mitochondrial membrane potential (▵Ψm) due to an inhibition of Complex I, which is partially compensated by an overactivation of Complex II. This complex activity imbalance leads to ROS generation in both mitochondrial matrix and cytosol, which results in glutathione depletion and increased lipid peroxidation. Preventing this increase in lipid peroxidation, in neurons, protects against in cell death. This work describes the pathophysiological properties of the mitochondria in neurons from a FRDA mouse model and shows that lipid peroxidation could be an important target for novel therapeutic strategies in FRDA, which still lacks a cure.


Subject(s)
Iron-Binding Proteins/genetics , Lipid Peroxidation/genetics , Membrane Potential, Mitochondrial , Mitochondria/metabolism , Neurons/metabolism , Animals , Cerebellum/metabolism , Cerebellum/pathology , Disease Models, Animal , Electron Transport Complex I/genetics , Electron Transport Complex I/metabolism , Electron Transport Complex II/genetics , Electron Transport Complex II/metabolism , Electron Transport Complex III/genetics , Electron Transport Complex III/metabolism , Friedreich Ataxia/genetics , Friedreich Ataxia/metabolism , Friedreich Ataxia/pathology , Gene Expression Regulation , Glutathione/metabolism , Humans , Iron/metabolism , Iron-Binding Proteins/metabolism , Mice , Mitochondria/pathology , Mutation , Neurons/pathology , Oxidative Stress , Primary Cell Culture , Reactive Oxygen Species/metabolism , Signal Transduction , Frataxin
3.
J Thromb Haemost ; 12(4): 519-27, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24450402

ABSTRACT

BACKGROUND: Blood platelets secrete upon activation of laminins 411/421 and 511/521, large adhesive proteins mainly found in the basement membranes of blood vessels and other tissues. At present, the subcellular localization and secretion mechanisms of platelet laminins are largely unknown. OBJECTIVES: Our aim was to compare the subcellular localization of laminins 411/421 and 511/521 and specific granule markers in platelets. We also elucidated the role of microvesicles and exosomes in laminin release in platelet activation. METHODS: We studied laminin and granule marker protein localization in platelets by using immunofluorescence confocal microscopy and immunoelectron microscopy. Microvesicles and exosomes were separated from material released from platelets on activation by thrombin. The expression of laminins in microvesicles and exosomes was studied by using SDS-PAGE and Western blotting as well as by flow cytometric analysis. The exosomes were immunoprecipitated with magnetic microbeads coated with anti-CD63 antibodies. RESULTS AND CONCLUSIONS: We demonstrate that laminins 411/421 and 511/521 are present in compartments of platelets that do not express α-granule, dense granule, or lysosome marker proteins. Moreover, laminins secreted by activated platelets are mostly found in microvesicles shed from the plasma membrane, while their presence in simultaneously released exosomes is minimum.


Subject(s)
Blood Platelets/metabolism , Cytoplasmic Granules/metabolism , Laminin/metabolism , Basement Membrane/metabolism , Blood Platelets/cytology , Cell Adhesion , Exosomes/metabolism , Extracellular Matrix/metabolism , Flow Cytometry , Humans , Microscopy, Confocal , Microscopy, Fluorescence , P-Selectin/metabolism , Platelet Activation , Platelet Membrane Glycoprotein IIb/metabolism , Tetraspanin 30/metabolism
4.
Andrologia ; 37(1): 29-35, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15644060

ABSTRACT

Previous research has suggested an association between personality traits and coping, as well as between coping and sperm concentration. In the present study, both domains of research were combined, leading to the formulation of specific hypotheses. A total of 54 healthy volunteers were given questionnaires twice to assess personality traits and coping behaviour. Participants also produced up to three semen specimens. As hypothesized, active coping was correlated negatively with neuroticism (r = -0.59) and positively with conscientiousness (r = 0.56), whereas sperm concentration was correlated negatively with both active coping (r = -0.28) and conscientiousness (r = -0.37). The relationship between conscientiousness and sperm concentration did not appear to be mediated by active coping. Although the correlations were small, evidence is mounting that psychological aspects and male sperm parameters are not independent. The present findings, however, should not lead to the conclusion that conscientiousness and active forms of coping are characteristics of infertile patients.


Subject(s)
Adaptation, Psychological , Personality , Sperm Count , Humans , Male
5.
Biol Lett ; 1(2): 147-50, 2005 Jun 22.
Article in English | MEDLINE | ID: mdl-17148151

ABSTRACT

Cetacean strandings elicit much community and scientific interest, but few quantitative analyses have successfully identified environmental correlates to these phenomena. Data spanning 1920-2002, involving a total of 639 stranding events and 39 taxa groups from southeast Australia, were found to demonstrate a clear 11-13- year periodicity in the number of events through time. These data positively correlated with the regional persistence of both zonal (westerly) and meridional (southerly) winds, reflecting general long-term and large-scale shifts in sea-level pressure gradients. Periods of persistent zonal and meridional winds result in colder and presumably nutrient-rich waters being driven closer to southern Australia, resulting in increased biological activity in the water column during the spring months. These observations suggest that large-scale climatic events provide a powerful distal influence on the propensity for whales to strand in this region. These patterns provide a powerful quantitative framework for testing hypotheses regarding environmental links to strandings and provide managers with a potential predictive tool to prepare for years of peak stranding activity.


Subject(s)
Cetacea , Climate , Animals , Oceanography , Periodicity , Tasmania , Victoria , Wind
6.
Hum Reprod ; 20(3): 825-8, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15576383

ABSTRACT

BACKGROUND: Previous research on infertile males has delivered equivocal findings on the course of infertility distress in males. The present longitudinal study examines whether there are differentials associated with specific treatment experiences (i.e. duration of treatment, the diagnosis received, and treatment failure of assisted reproductive technologies). METHODS: The sample consisted of 118 patients who twice visited an andrology clinic on their own initiative for fertility work-ups. Baseline and follow-up examinations were > or = 6 months apart. Prior to each fertility work-up, patients completed a questionnaire assessing distress due to infertility. RESULTS: No uniform course of distress could be detected. A significant interaction between treatment experiences indicated that distress rises significantly only in those patients who were in treatment > or = 17 months and experienced treatment failure between the first and the second psychological evaluation. For the diagnosis of male infertility, however, neither a direct nor an indirect impact was identified. CONCLUSION: The present study indicates that the interaction of specific treatment experiences is associated with changes in distress of infertile males.


Subject(s)
Infertility, Male/parasitology , Infertility, Male/therapy , Reproductive Techniques, Assisted , Stress, Psychological/etiology , Adult , Humans , Longitudinal Studies , Male , Surveys and Questionnaires , Time Factors , Treatment Failure
7.
Hum Reprod ; 19(4): 954-9, 2004 Apr.
Article in English | MEDLINE | ID: mdl-15033952

ABSTRACT

BACKGROUND: Previous research has suggested an interaction between distress and male fertility. The present longitudinal study sought to deliver evidence for a negative impact of distress due to infertility on sperm concentration. METHODS: The sample consisted of 120 patients who twice visited an andrological clinic on their own initiative for fertility work-ups. Baseline and follow-up examinations were at least 6 months apart. Prior to each fertility work-up, patients completed a questionnaire assessing distress due to infertility. RESULTS: Path analyses revealed that the level of infertility distress at follow-up has a negative impact on the change in sperm quality from baseline to follow-up assessment. Distress scores were highly stable. As a consequence, the level of distress at baseline assessment provided only little additional information for the changes in sperm concentration. Further analysis suggested that the fertility status had no impact on infertility distress. CONCLUSION: The present study delivers the strongest evidence to date that distress due to infertility is a significant risk factor for a decrease in sperm quality.


Subject(s)
Infertility, Male/psychology , Sperm Count , Stress, Psychological/physiopathology , Humans , Longitudinal Studies , Male , Stress, Psychological/psychology , Surveys and Questionnaires
8.
Physiol Genomics ; 16(3): 334-40, 2004 Feb 13.
Article in English | MEDLINE | ID: mdl-14679302

ABSTRACT

Many of the spinocerebellar ataxias (SCAs) are caused by expansions of CAG trinucleotide repeats encoding abnormal stretches of polyglutamine. SCA3 or Machado-Joseph disease (MJD) is the commonest dominant inherited ataxia disease, with pathological phenotypes apparent with a CAG triplet repeat length of 61-84. In this study a mouse model of SCA3 has been examined which was produced using a human yeast artificial chromosome containing the MJD gene with a CAG triplet expansion of 84 repeats. These mice have previously been shown to possess a mild progressive cerebellar deficit. NMR-based metabolomics/metabonomics in conjunction with multivariate pattern recognition identified a number of metabolic perturbations in SCA3 mice. These changes included a consistent increase in glutamine concentration in tissue extracts of the cerebellum and cerebrum and spectra obtained from intact tissue using magic angle spinning (1)H-NMR spectroscopy. Furthermore, these profiles demonstrated metabolic abnormalities were present in the cerebrum, a region not previously implicated in SCA3. As well as an increase in glutamine both brain regions demonstrated decreases in GABA, choline, phosphocholine and lactate (representing the summation of lactate in vivo, and postmortem glycolysis of glucose and glycogen). The metabolic changes are discussed in terms of the formation of neuronal intranuclear inclusions associated with SCA3. This study suggests high-resolution (1)H-NMR spectroscopy coupled with pattern recognition may provide a rapid method for assessing the phenotype of animal models of human disease.


Subject(s)
Brain/metabolism , Disease Models, Animal , Machado-Joseph Disease/genetics , Machado-Joseph Disease/metabolism , Nerve Tissue Proteins/genetics , Animals , Ataxin-3 , Brain/pathology , Cerebellum/metabolism , Cerebellum/pathology , Choline/metabolism , Glucose/metabolism , Glutamine/metabolism , Glycogen/metabolism , Humans , Lactic Acid/metabolism , Machado-Joseph Disease/pathology , Magnetic Resonance Spectroscopy , Mice , Mice, Transgenic , Nuclear Proteins , Phenotype , Phosphorylcholine/metabolism , Repressor Proteins , Telencephalon/metabolism , Telencephalon/pathology , Transcription Factors , Trinucleotide Repeat Expansion/genetics , gamma-Aminobutyric Acid/metabolism
9.
Neurogenetics ; 3(4): 185-93, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11714098

ABSTRACT

We have generated and characterised transgenic mice that contain the entire Friedreich's ataxia gene (FRDA) within a human YAC clone of 370 kb. In an effort to overcome the embryonic lethality of homozygous Frda knockout mice and to study the behaviour of human frataxin in a mouse cellular environment, we bred the FRDA YAC transgene onto the null mouse background. Phenotypically normal offspring that express only YAC-derived human frataxin were identified. The human frataxin was expressed in the appropriate tissues at levels comparable to the endogenous mouse frataxin, and it was correctly processed and localised to mitochondria. Biochemical analysis of heart tissue demonstrated preservation of mitochondrial respiratory chain function, together with some increase in citrate synthase and aconitase activities. Thus, we have demonstrated that human frataxin can effectively substitute for endogenous murine frataxin in the null mutant. Our studies are of immediate consequence for the generation of Friedreich's ataxia transgenic mouse models, and further contribute to the accumulating knowledge of human-mouse functional gene replacement systems.


Subject(s)
Chromosomes, Artificial, Yeast , Friedreich Ataxia/genetics , Friedreich Ataxia/physiopathology , Iron-Binding Proteins , Mice, Knockout/genetics , Animals , Disease Models, Animal , Genes, Lethal , Homozygote , Humans , Mice , Phenotype , Phosphotransferases (Alcohol Group Acceptor)/genetics , Transgenes/genetics , Frataxin
10.
Behav Res Ther ; 39(3): 299-308, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11227811

ABSTRACT

In the present study manual-based cognitive-behavioral therapy for bulimia nervosa was evaluated on an unselected sample of an out-patient service facility. A total of 73 female patients who asked for treatment received the primary diagnosis of bulimia nervosa. Of these, 67 took up treatment. Treatment was completed by 66 patients. Outcome variables were the number of binge episodes along with questionnaire scores for restraint eating, emotional eating, body dissatisfaction and depressiveness. At the end of treatment and 1 year after the end of treatment significant improvements were found in all outcome variables. Effect sizes for outcome variables were within the range of those of controlled research. Therefore, the present study delivered empirical evidence that manual-based cognitive-behavioral therapy is an effective treatment for bulimia nervosa not only within the restricted area of research.


Subject(s)
Bulimia/therapy , Cognitive Behavioral Therapy , Adolescent , Adult , Bulimia/psychology , Community Mental Health Centers , Female , Humans , Internal-External Control , Outcome and Process Assessment, Health Care , Personality Inventory
11.
Patient Educ Couns ; 42(3): 239-45, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11164323

ABSTRACT

The purpose of the present study was to identify characteristics of male patients that could be relevant for the uptake of psychological couple counselling for infertility. Therefore, 94 male patients who participated in psychological couple counselling were compared to 134 unselected infertility patients who attended an andrological clinic. Counselling users showed higher scores for depression and anxiety as well as a higher number of impaired sperm parameters. Multivariate analysis revealed that beyond the level of depression the number of impaired sperm parameters delivered additional information about the probability of a patient using counselling. For interpretation of these results the former research was broadly reviewed. It is suggested that an increased level of distress, the feeling of being responsible for infertility and few marital difficulties are relevant for the usage of couple counselling by male infertility patients. Practical consequences are discussed.


Subject(s)
Couples Therapy , Infertility, Male/psychology , Adult , Case-Control Studies , Germany , Humans , Male , Motivation , Multivariate Analysis
14.
Br J Clin Psychol ; 38(3): 279-87, 1999 09.
Article in English | MEDLINE | ID: mdl-10532149

ABSTRACT

OBJECTIVES: This study was designed to investigate the impact of mood changes on body width estimation in women with bulimia nervosa. DESIGN: A pre-post controlled experimental design was chosen. METHOD: Mood changes were induced in 40 women with bulimia nervosa, 20 women with panic disorder and 40 women with no diagnosis of a psychological disorder. A combination of autobiographical memory method and music induction method was used to induce positive and negative mood, respectively. Before and after mood induction a video distorting technique was used for body width estimation. RESULTS: Induction of negative mood increased and induction of positive mood decreased the body width estimations of women with bulimia. Patients with panic disorder and 'healthy' controls did not show these changes after mood induction. CONCLUSION: The findings suggest that change in mood state rather than the more habitual mood quality are relevant for bulimic women's body perception.


Subject(s)
Affect/physiology , Body Image , Bulimia/psychology , Depression/psychology , Adult , Analysis of Variance , Bulimia/physiopathology , Case-Control Studies , Female , Humans , Panic Disorder/psychology , Personal Satisfaction
15.
J Neurol Neurosurg Psychiatry ; 67(2): 217-9, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10406994

ABSTRACT

A family with pseudodominant Friedreich's ataxia is described showing marked variation of phenotype between affected siblings. The mother of this family (III-3) developed a spastic ataxic tetraplegia with neuropathy at 34 years of age; her husband, who was unrelated, was clinically normal. Of their nine children, two (IV-2, IV-3), including one with multiple sclerosis (IV-3), developed a mild spinocerebellar degeneration in the third decade. Three in their late 20s had an asymptomatic spinocerebellar degeneration (IV-4, IV-5, IV-6) and one was confined to a wheelchair at 15 years with typical Friedreich's ataxia (IV-9). Three other siblings (IV-1, IV-7, IV-8) were clinically normal. The father proved to be heterozygous for the triplet repeat expansion at the Friedreich's ataxia locus and all clinically affected members were homozygous for alleles in the expanded size range. This family confirms that homozygote-heterozygote mating is the genetic basis for some families with apparent autosomal dominant Friedreich's ataxia.


Subject(s)
Friedreich Ataxia/genetics , Genes, Dominant , Genetic Variation , Adult , Alleles , Female , Friedreich Ataxia/physiopathology , Heterozygote , Homozygote , Humans , Male , Middle Aged , Neural Conduction/physiology , Pedigree , Phenotype , Spinocerebellar Degenerations/genetics , Trinucleotide Repeat Expansion
16.
Hum Reprod ; 14(6): 1487-92, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10357965

ABSTRACT

Infertility represents a serious stressor for some patients as well as a risk factor for a decrease in sperm quality. The purpose of the present study was to identify coping strategies that went along with both better emotional and physical adjustment to infertility. The sample consisted of 63 patients who contacted an andrological clinic more than one time. Prior to clinical examination, patients filled out a questionnaire referring to the way in which they coped with their wives' previous menstruation. Participants also completed a scale assessing perceived distress due to infertility. Change in sperm concentration since baseline semen analysis and the level of distress were used to evaluate patient's adjustment. The better-adjusted patients showed less prominent overall coping efforts, and a higher proportion of distancing coping strategies. An improvement in sperm quality also was associated with a low cognitive involvement in infertility. Situational uncontrollability of infertility could be a moderator of the effectiveness of coping employed by the better-adjusted patients. In addition, the coping behaviour related to better adjustment could be due to a dispositional stress resistance factor. For clinical implementation of the findings, the attitudes of a patient and the expectations of his wife have to be taken into consideration.


Subject(s)
Adaptation, Psychological , Emotions , Infertility, Male/psychology , Spermatozoa/physiology , Adult , Counseling , Humans , Male , Middle Aged , Sperm Count , Surveys and Questionnaires
17.
Psychother Psychosom ; 68(2): 95-101, 1999.
Article in English | MEDLINE | ID: mdl-10026461

ABSTRACT

BACKGROUND: In this study we examined whether stress has a negative influence on sperm quality. To investigate this issue we developed a scale assessing perceived stress resulting from infertility. METHODS AND RESULTS: The Infertility Distress Scale was constructed based on the data of 158 infertility patients contacting an andrological clinic for the first time. The Infertility Distress Scale consists of items assessing self-reported stress, different appraisals of infertility and cognitive involvement in infertility. The scale was shown to have good psychometric properties. Changes in sperm quality were predicted by this scale for 69 patients. Changes in sperm concentration and sperm motility were predicted correctly 75.4 and 65.6% of the time, respectively. While these prediction accuracies were significantly better than chance prediction, the Infertility Distress Scale had no predictive value for changes in morphology. CONCLUSION: Results indicate that distress caused by infertility is a risk factor for a decrease in sperm quality.


Subject(s)
Infertility, Male/etiology , Sperm Count , Sperm Motility , Stress, Psychological/complications , Stress, Psychological/psychology , Adult , Humans , Infertility, Male/psychology , Male , Middle Aged , Predictive Value of Tests , Psychiatric Status Rating Scales , Psychometrics , Spermatozoa/abnormalities , Surveys and Questionnaires
18.
Psychother Psychosom ; 68(1): 15-21, 1999.
Article in English | MEDLINE | ID: mdl-9873237

ABSTRACT

BACKGROUND: The purpose of this pilot study was to evaluate the impact of a 6-month cognitive-behavioral therapy for infertile couples. METHODS: Seventeen idiopathic infertile couples participated in a therapy program comprised of modules to behaviorally optimize the chance of conception, improve sexual functioning and satisfaction, reduce thoughts of helplessness and, if necessary, improve marital communication skills. Pre- to posttreatment changes in the therapy group were compared to changes in two control groups. RESULTS: The therapy group showed an improvement in sperm concentration, a reduction in thoughts of helplessness and a decrease in marital distress. By the end of therapy participants practiced timed intercourse more reliably and reported unchanged sexual pleasure and satisfaction during the nonfertile period of the menstrual cycle. At the 6-month follow-up, problem-focused thoughts had decreased. The live birth rate was higher in the therapy group than in epidemiological samples. CONCLUSION: Preliminary data suggest that cognitive-behavioral treatment may be an effective approach for the treatment of infertility.


Subject(s)
Cognitive Behavioral Therapy/methods , Health Knowledge, Attitudes, Practice , Infertility/therapy , Adult , Body Temperature , Coitus/psychology , Female , Follow-Up Studies , Humans , Infertility/psychology , Male , Pilot Projects , Pregnancy Rate , Semen/cytology , Statistics, Nonparametric
19.
Genomics ; 42(1): 170-2, 1997 May 15.
Article in English | MEDLINE | ID: mdl-9177790

ABSTRACT

The STM7 gene encodes a novel phosphatidylinositol-4-phosphate 5-kinase (PtdInsP 5-kinase) that is subject to alternative splicing and developmental control. We have recently presented data indicating that several splice variants of STM7 incorporate elements of the X25 sequence, previously implicated in the pathogenesis of Friedreich's ataxia by the detection of an intronic GAA repeat expansion as the predominant mutation in affected individuals. We now report the exon-intron structure of STM7.I and primer sequences designed to facilitate full characterization, including details relating to a novel exon (STM7; exon 17) derived from the 3'-UTR of the PRKACG gene. The detection of a mutation(s) within these exons would provide additional support for the hypothesis that a defect in phosphoinositide metabolism gives rise to the disease phenotype.


Subject(s)
Iron-Binding Proteins , Phosphotransferases (Alcohol Group Acceptor)/genetics , Alternative Splicing , Base Sequence , DNA Primers/genetics , Exons , Friedreich Ataxia/enzymology , Friedreich Ataxia/genetics , Humans , Introns , Minisatellite Repeats , Molecular Sequence Data , Mutation , Phenotype , Polymerase Chain Reaction , Trinucleotide Repeats , Frataxin
20.
Nat Genet ; 14(2): 157-62, 1996 Oct.
Article in English | MEDLINE | ID: mdl-8841185

ABSTRACT

The STM7 gene on chromosome 9 was recently 'excluded' as a candidate for Friedreich's ataxia following the identification of an expanded intronic GAA triplet repeat in the adjacent gene, X25, in patients with the disease. Using RT-PCR, northern and sequence analyses, we now demonstrate that X25 comprises part of the STM7 gene, contributing to at least four splice variants, and report the identification of new coding sequences. Functional analysis of the STM7 recombinant protein corresponding to the reported 2.7-kilobase transcript has demonstrated PtdlnsP 5-kinase activity, supporting the idea that the disease is caused by a defect in the phosphoinositide pathway, possibly affecting vesicular trafficking or synaptic transmission.


Subject(s)
Friedreich Ataxia/genetics , Genes/genetics , Iron-Binding Proteins , Phosphotransferases (Alcohol Group Acceptor)/genetics , Proteins/genetics , Adult , Alternative Splicing/genetics , Amino Acid Sequence , Chromosome Mapping , Exons/genetics , Friedreich Ataxia/enzymology , Humans , Molecular Sequence Data , Organ Specificity , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Placenta , RNA, Messenger/analysis , RNA, Messenger/genetics , Recombinant Fusion Proteins/metabolism , Sequence Alignment , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Frataxin
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