Thesis (Doctoral)--Göteborg University, 2006. / "1101-718X"--T.p. verso. Includes bibliographical references.

xv, 106 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Myotonic Dystrophy type I (DM1) is caused by muscleblind protein sequestration to aberrantly expanded CUG repeats. When muscleblind is sequestered it can no longer fulfill its role as an alternative splicing regulator, leading to mis-splicing events in both humans and Drosophila . The muscleblind protein family's RNA binding specificity has been minimally characterized. Only one pre-mRNA target in humans, cardiac troponin T (cTNT), has a known MBNL1 binding site. In order to understand muscleblind's RNA binding specificity and identify a consensus binding motif, systematic evolution of ligands by exponential enrichment (SELEX) was performed on both the Drosophila muscleblind protein, Mbl, and the human ortholog, MBNL1. Drosophila has provided a useful model for studying the disease mechanism of DM1. Studies of Mbl's RNA binding specificity to CUG repeats concluded that replacing the U-U mismatches with different pyrimidine-pyrimidine mismatches was tolerated, but no other mutations were. To understand Mbl's RNA binding specificity, SELEX was performed. After 6 rounds, several sequences were identified that bound with high affinity, all containing the 5'-AGUCU-3' consensus motif. One sequence, SELEX RNA 20 was analyzed further. In addition to the guanosine in the consensus motif of SELEX RNA 20, two other guanosines were shown to be protected by Mbl in a footprinting assay, indicating that Mbl has a strong preference for binding guanosine. Also, two "tail" regions of SELEX RNA 20 were shown to be single stranded and required for binding by Mbl. These results indicate that Mbl is a highly specific RNA binding protein with preference for both single and double stranded guanosine-rich regions. A doped SELEX was performed on MBNL1's binding site from the cTNT pre-mRNA to determine which sequences and structural aspects were important for recognition by MBNL1. Pool 5 RNA sequences bound with high affinity, and the motif 5'-YGCUU-3' was selected. This motif was then used to identify new MBNL1 binding sites in pre-mRNAs regulated by MBNL1, SERCA1 and MBNL1. The identification of this motif and two new MBNL1 sites provide insight into MBNL1-mediated alternative splicing. This dissertation includes both my previously published co-authored material and my unpublished co-authored material. / Adviser: J. Andrew Berglund

Myotonic Dystrophy type 1 (DM1), the most common form of adult muscular dystrophy (~1:8000) currently has no effective treatment. In DM1, expansion of a tri-nucleotide repeat in the 3' UTR of the DMPK gene results in DMPK mRNA hairpin structures, aggregating as insoluble ribonuclear foci. The resulting mis-regulation of important splicing factors, causes the inclusion of fetal exons in dozens of transcripts that contribute to the disease phenotype. In order to identify novel gene targets and kinase signalling pathways for potential therapeutics we have performed a high-throughput RNAi. RNA foci were visualized and quantified by in-situ hybridization. From our screen, we have identified a novel gene, PACT, as a modulator of foci integrity and that PACT knockdown can induce MBNL1 protein levels. The identified signalling complex represents a valid target for DM1 therapeutics. Our data further emphasizes the utility of RNAi screens in identifying disease-associated genes.

INTRODUÇÃO: A disfagia orofaríngea e os distúrbios de motilidade esofágica são considerados as mais importantes causas de pneumonia aspirativa em pacientes com distrofia miotônica. O objetivo deste estudo foi avaliar as características clínicas da motricidade orofacial e a deglutição de indivíduos com distrofia miotônica (DM1), utilizando um protocolo clínico padronizado e eletromiografia de superfície (EMGs). MÉTODO: Os participantes foram divididos em dois grupos: G1-composto por 20 adultos com DM1; G2-composto por 20 voluntários saudáveis, os participantes foram pareados por idade e gênero com G1 para a análise estatística. Foi realizada a avaliação das estruturas e funções orofaciais, utilizando um protocolo clínico padronizado, e mensurada a atividade mioelétrica da deglutição por meio da EMGs, com eletrodos localizados em quatro grupos musculares: (1) orbicular da boca, (2) masseter, (3) musculatura suprahioidea e (4) extrínseca da laringe. A atividade mioelétrica foi medida durante o repouso muscular e durante a deglutição de saliva e de 16,5ml e 20ml de água. Os traçados da EMGs foram avaliados durante o inicio (onset), pico e o término (offset), dos evento da deglutição. A análise estatística incluiu a ANOVA de duplo fator para intragrupos e intergrupos e o teste de Bonferroni para correções de comparações múltiplas. RESULTADOS: Pacientes com DM1 apresentaram déficits em posição, postura e mobilidade dos órgãos miofuncionais orofaciais, e nas funções de mastigação e deglutição. Além disso, os resultados da EMGs para diferentes tarefas de deglutição indicaram maior atividade muscular do orbicular da boca e maior duração da ativação muscular para os músculos: orbicular da boca, masseter e extrínseco de laringe. Não foi observado aumento significativo na amplitude da EMGs, nos pacientes com DM1, quando comparado aos resultados obtidos no teste de deglutição normal com o teste de estresse. CONCLUSÕES: A maior duração da deglutição na EMGs no grupo DM1, possivelmente está relacionada a miotonia e/ou incoordenação dos músculos envolvidos no processo da deglutição ou pode estar relacionado a uma adaptação fisiológica para uma deglutição segura. A identificação precoce dos distúrbios da deglutição permite reabilitação precoce oral, o que poderia diminuir o risco de pneumonia por aspiração nesta população. / INTRODUCTION: Oropharyngeal dysphagia and oesophageal motility disorders were found to be the most important reasons causing aspiration pneumonia in patients with myotonic dystrophy. The purpose of this report was to evaluate clinical characteristics of the oral motor movements and swallowing of individuals with myotonic dystrophy type 1 (DM1), using a standardized clinical protocol and surface electromyography (sEMG). METHOD: Participants were 40 individuals divided in two groups: G1- composed by 20 adults with DM1; G2- composed by 20 healthy volunteers paired by age and gender to individuals in G1. Participants of all groups underwent clinical assessment of the orofacial structures and functions using a standardized clinical protocol. The myoelectric activity of swallowing was measured using sEMG. Four muscle groups were examined: (1) the orbicularis oris superior and inferior; (2) the masseter; (3) the submental muscle group; and (4) the laryngeal strap muscles. Muscle activity was measured during rest, during dry swallows and during the swallowing of 16.5ml and 20ml of water. Surface EMG traces were evaluated for onset, peak and offset of activity during swallow events. The statistical analysis included the one-way ANOVA with two factors for within and between group comparisons and the Bonferroni correction for multiple comparisons. RESULTS: Patients with DM1 presented deficits in posture, position and mobility of the oral motor organs, as well as compromised mastication and deglutition. Moreover, sEMG results for different swallowing tasks indicated higher muscle activity for the orbicularis oris and longer durations of muscle activation for the orbicularis oris, masseter and laryngeal strap muscles. When considering within group comparisons, DM1 patients did not present a significant increase of sEMG amplitude during the stress test in comparison with the normal swallow test. CONCLUSION: Compared to healthy individuals, patients with DM1 presented longer times to pass a bolus from the oral cavity to the esophagus. The larger duration of sEMG in the DM1 group is possibly related to myotonia and/or incoordination of the muscles involved in the swallowing process or could reflect a physiological adaptation for safe swallowing. Early identification of swallowing disorders enables early oral rehabilitation, which in turn could decrease the risk of aspiration pneumonia in this population.

Muscleblind-like 1 (MBNL1) is a ubiquitously expressed RNA binding protein that regulates the alternative splicing of a variety of transcripts. In Myotonic Dystrophy (DM) aberrant cellular localization of MBNL1 results in disease-associated mis-splicing of several MBNL1 target pre-mRNAs. Due to its role in DM pathogenesis, MBNL1 has been a topic of intense study for the last decade, however many open mechanistic questions remain regarding how MBNL1 recognizes RNA substrates to mediate splicing. The RNA recognition motif for MBNL1, 5'-YGCY-3', was defined herein. This motif was used to identify novel MBNL1 binding sites within regulated transcripts and create synthetic MBNL1-regulated splicing reporters. MBNL1 contains four zinc finger (ZF) RNA binding domains arranged into two pairs of two ZFs. A comprehensive, combinatorial mutagenic study of MBNL1 was conducted to determine the role of each ZF in RNA binding and splicing activity. Functional analysis of the mutant proteins in cellular splicing assays and assessment of RNA binding activity demonstrated that the ZF pairs (i.e. ZF1-2 or ZF3-4) do not have equivalent activity. The ZF1-2 pair is responsible for MBNL1's high affinity RNA binding and splicing activity, whereas the ZF3-4 pair has reduced affinity for RNA and impaired ability to regulate splicing of some transcripts. Hierarchical clustering analysis revealed that two distinct classes of MBNL1-regulated splicing events exist within the small set of splicing events examined. For Class II splicing events the binding and splicing activity for the ZF mutants correlated well. However, for Class I events there was no significant correlation between RNA binding and splicing activity. For pre-mRNAs in the latter class it appears that MBNL1 exerts surprisingly robust splicing activity in the absence of strong RNA binding, suggesting that MBNL1 may be recruited to some pre-mRNA substrates through protein-protein interactions. This study provides the first demonstration that functionally distinct classes of MBNL1-mediated splicing events exist in terms of requirements for different ZFs and the importance of RNA binding. This dissertation includes previously published and unpublished co-authored material as well as recently co-authored material that has been submitted for publication.

Myotonic dystrophy (DM) is an inherited disease characterized by myotonia, insulin resistance, cardiomyopathy, and cognitive deficiencies. DM is a triplet repeat disorder, meaning that affected individuals carry anywhere between 50 and thousands of CTG/CCTG repeats in their genetic makeup. When transcribed into RNA, these repeats become “toxic” in the sense that they serve to bind and sequester important RNA binding proteins. One such family of proteins, the Muscleblind-like (MBNL) family, is important in the regulation of alternative mRNA splicing, and thus the sequestration of MBNL proteins leads to a number of mis-splicing events. Many of these events are directly correlated to DM symptoms. While there is no known cure for DM, the use of small molecules to treat symptoms is a well-characterized therapeutic tactic with immense promise. Pentamidine is a small molecule that was found to reverse mis-splicing in both DM cell and mouse models. Mechanistically, this molecule is particularly unique because unlike many small molecules, which physically displace MBNL from the toxic CUG RNA, pentamidine reduces CUG RNA levels, possibly through inhibition of CTG transcription. Chapter I summarizes alternative splicing mechanisms and regulation, defines MBNL protein structure and function, describes DM pathophysiology and molecular mechanism, and finally provides an overview of pentamidine characterization as a small molecule therapeutic. Chapter II reports the development of an in vitro T7 transcription assay, which allowed us to compare the relative efficacy by which pentamidine is able to inhibit the transcription of various repeat and non-repeat DNA sequences. This chapter further reports the characterization of a series of methylene linker analogues of pentamidine, which were also characterized through the T7 transcription assay. Chapter III details our thorough structure-activity relationship investigation of bisbenzamidine analogues of pentamidine, both in in vivo and in vitro models. Chapter IV describes our characterization of actinomycin D, a known transcription inhibitor and chemotherapeutic, within the DM disease framework. Chapter V summarizes these data, which ultimately serve as a proof of concept for the potential of CTG transcription inhibition in therapeutic contexts and broadly describe their application in other repeat diseases. This dissertation contains previously published and unpublished co-authored material. / 10000-01-01

La maladie de Steinert ou dystrophie myotonique de type 1 (DM1), dystrophie musculaire la plus commune chez l’adulte, est causée par l’expansion instable de triplets CTG dans la région 3’ non traduite du gène DMPK (Dystrophia Myotonica Protein Kinase). Cette maladie multisystémique, affectant principalement les muscles squelettiques et le cœur, est liée à l’épissage. En effet, les CUG exp forment des structures secondaires dans le noyau capables de séquestrer la protéine MBNL1, facteur d’épissage alternatif. En parallèle, un autre facteur d’épissage alternatif, CELF1 est stabilisé. La dérégulation de la balance entre ces deux protéines cause des défauts d’épissage, responsables de certains symptômes de la maladie, comme la myotonie, des défauts de conduction cardiaque et une résistance à l’insuline, causés respectivement par l’épissage aberrant du canal chlorure Clcn1, du canal sodique SCN5A et du récepteur à l’insuline IR. De plus, des dérégulations indépendantes de l’épissage sont aussi mises en jeu dans la DM1 mais leur responsabilité dans l’apparition des symptômes de la maladie reste à identifier. Pour identifier des dérégulations transcriptionnelles indépendantes de l’épissage mais liées à la progression et à la sévérité des symptômes, nous avons généré de nouveaux modèles drosophile de la DM1 avec un nombre croissant de répétitions CTG. Ces modèles étudiées au stade larvaire récapitulent les caractéristiques majeures de la DM1 : la formation de foci et une hypercontractilité musculaire. De plus, nous avons identifié dans ce modèle des dérégulations géniques indépendantes de l’épissage mais dépendantes du nombre de répétitions CTG. Notamment, une atténuation de Gbe1, codant pour une enzyme de branchement du glycogène pourrait participer aux phénotypes musculaires. Afin d’étudier les symptômes cardiaques de la maladie qui touchent 80% des patients et représentent la deuxième cause de mortalité, nous avons utilisé le modèle DM1 de drosophile développé dans notre équipe, et réalisé des analyses physiologiques cardiaques sur des mouches adultes qui expriment 960 CTG dans le cœur (Hand>DM1 960 ), un ARNi pour Mbl, l’orthologue de MBNL1, ou qui surexpriment l’orthologue de CELF1, Bru-3. Ces trois modèles DM1 reproduisent les symptômes cardiaques majeurs observés chez les patients comme des défauts de conduction, de l’arythmie (fibrillation) ou encore une cardiomyopathie dilatée. Afin d’identifier des dérégulations géniques susceptibles d’être responsables de ces défauts, nous avons réalisé une analyse transcriptomique par séquençage ARN après collection de l’ARN spécifique du cœur par la technique du TU-tagging. Les gènes dérégulés identifiés dans ces contextes ont été classés en fonction de leur conservation et du niveau de dérégulation. Parmi eux, la surexpression dans le cœur adulte de Straightjacket (Stj), l’orthologue de CACNA2D4 qui code pour une sous-unité d’un canal calcique voltage- dépendant, cause des défauts de conduction et de la fibrillation, mimant ce qui a été observé en contexte DM1 960 et gain de fonction pour Bru-3. Dans l’avenir, nous aimerions confirmer son implication dans la physiologie cardiaque et en particulier dans la DM1 en analysant son expression chez les patients présentant des défauts cardiaques similaires. / The most common muscular dystrophy found in adults, Steinert disease or Myotonic Dystrophy Type 1 (DM1) is caused by an unstable CTG repeat expansion in the 3’ untranslated region of the Dystrophia Myotonica Protein Kinase (DMPK) gene. This multisystemic disease, affecting particularly skeletal muscles and the heart, is called a spliceopathy because it involves the sequestration of the MBNL1 splicing factor by the expanded CUG-carrying transcripts and the stabilization of the CELF1 splicing factor. The misbalance of these two factors is responsible for splicing defects that cause most of the disease symptoms, like myotonia, conduction defects and arrhythmia but also insulin resistance, respectively associated to missplicing of Clcn1, SCN5A and IR. Moreover, DM1 toxicity is also associated to splice-independent deregulations but their link to disease symptoms remain poorly understood. To identify transcriptional deregulations independent of splicing and associated to disease progression and severity, we generated new DM1 Drosophila models with increasing number of CTG repeats. These larval models recapitulated the main DM1 muscular symptoms such as hypercontractility and foci formation and allowed us identifying gene deregulations independent of splicing. Among them, Gbe1 coding for a glycan branching enzyme is attenuated in the DM1 context in a CTG-repeat dependant manner and could participate in the severity of muscle phenotypes. To better understand the causes of cardiac symptoms that represent the second cause of death and affecting 80% of DM1 patients, we took advantage of our DM1 inducible Drosophila model and performed phenotypic analyses on the heart of adult flies expressing: 960 CTG specifically in the heart (Hand>DM1 960 ), a RNAi for the Drosophila MBNL1 orthologue (Muscleblind, Mbl) or overexpressing the CELF1 orthologue (Bruno-3, Bru3). These DM1 adult models display conduction abnormalities, arrhythmicity (fibrillation) and dilated cardiomyopathy (DCM). Thus, these three pathogenic contexts recapitulated collectively the main DM1 cardiac symptoms and prompted us to perform transcriptional profiling to identify symptom’s-associated gene deregulations. To identify new molecular actors responsible for the DM1 associated heart defects, we performed cardiac cell-specific transcriptional analyses by RNA-sequencing, using TU-tagging technique. Then, we selected deregulated candidate genes that could be linked to the particular observed phenotypes and ranked depending on their conservation and deregulation level. Among them, increased expression of Straightjacket (Stj), the CACNA2D4 orthologue, encoding a subunit of voltage- dependent calcium channel results in fibrillation and conduction defects, thus mimicking cardiac symptoms found in DM1 960 and Bru-3 gain of function contexts in which it was up- regulated. Whether identified candidates are deregulated in DM1 patients displaying cardiac abnormalities remains to be tested.

La Dystrophie Myotonique de type 1 (DM1) est cause par l’expansion anormale d’un triplet CTG dans la partie 3’UTR du gène DMPK, entrainant l’agrégation du transcrit mutant dans des inclusions ribonucléoprotéiques appelées foci. D’après plusieurs études structurales sur des courtes répétitions CUG, il a été proposé que les expansions CUG se replient en une structure en tige-boucle qui interfère avec l’activité de plusieurs facteurs lié au métabolisme de l’ARN et altère leur fonction cellulaire. Le facteur d’épissage muscleblind-like 1 (MBNL1) a été identifié par sa capacité à interagir avec les répétitions CUG. In vivo, ces répétitions entrainent la séquestration de cette protéine aboutissant en une déplétion nucléaire. Un autre facteur d’épissage, la CUG Binding protein (CUGBP1), est également impliqué dans la pathologie. Au lieu d’être séquestré par les répétitions, la stabilité protéique de CUGBP1 est augmentée dans les tissus DM1 entrainant un gain d’activité pour ce facteur. La séquestration de MBNL1 et la stabilisation de CUGBP1 résultent en la dérégulation de l’épissage alternatif de plusieurs transcrits musculaires et du cerveau et la réexpression d’isoformes protéiques fœtales dans les tissus adultes. Cependant, de récentes études suggèrent que d’autres facteurs ou voies de signalisation que celles faisant intervenir MBNL1 et CUGBP1 pourraient être impliquées dans la pathologie DM1.Le but de mon travail de thèse a été d’identifier de nouveaux facteurs ayant la capacité d’interagir avec les répétitions CUG. A l’aide d’une purification sur chromatographie d’affinité utilisant un ARN contenant 95 répétitions CUG comme appât, nous avons identifié l’ARN hélicase p68/DDX5. p68 fait partie de la famille des protéines DEAD-box, caractérisée par un core protéique conservé constitué de neufs domaines hautement conservés, dont le motif DEAD, à l’origine du nom de ces protéines. p68 est impliquée dans de nombreux aspects du métabolisme de l’ARN, dont la transcription, l’épissage, l’export, la traduction et la dégradation des ARN. Nous avons montré, que p68 colocalise avec les foci CUG dans un modèle cellulaire exprimant la partie 3’UTR du gène DMPK contenant de longues répétitions CTG. Nous avons identifié que p68 augmente l’interaction de MBNL1 sur les répétitions CUG et une structure secondaire particulière d’un élément régulateur de l’ARN pré-messager cardiac Troponin T (TNNT2), dont l’épissage est dérégulé dans la pathologie. L’insertion de mutations dans le core de l’hélicase de p68 abolit l’effet de p68 sur la fixation de MBNL1 ainsi que la colocalisation de p68 avec les expansions CUG in vivo, suggérant que le remodelage des structures secondaires ARN de manière ATP-dépendante par p68 facilite l’interaction de MBNL1. Nous trouvons également que la compétence de p68 pour réguler l’inclusion de l’exon alternatif 5 de TNNT2 dépend de l’intégrité des sites de fixation de MBNL1.Nous proposons que p68 agit comme un modificateur de l’activité de MBNL1 sur ces cibles d’épissage ainsi que sur les expansions CUG à l’origine de la pathologie. / Myotonic Dystrophy type I (DM1) is caused by an abnormal expansion of CTG triplets in the 3’ UTR of the DMPK gene, leading to the aggregation of the mutant transcript in nuclear RNA foci. Based on structural studies on short CUG repeats, it has been proposed that expanded CUG repeats fold into an imperfect hairpin structure that interferes with the activities of RNA binding proteins and alters their normal cellular function. The muscleblind-like 1 protein (MBNL1) was identified by its ability to bind to CUG repeats. It has been shown that the expanded mutant transcript promotes the sequestration of the MBNL1 splicing factor in nuclear RNA foci. CUGBP1 is another splicing factor that is involved in DM1. Instead of being sequestered by the repeats, the steady-state level of CUGBP1 is increased in DM1 tissues, leading to a gain of activity of the protein. The sequestration of MBNL1 and the up-regulation of CUGBP1 in DM1 results in the misregulation of alternative splicing of a subset of muscle and brain-specific transcripts, leading to the re-expression of fetal isoforms in adult tissues. However, several recent studies suggest that factors or signaling pathways other than MBNL1 and CUGBP1 could be involved in DM1 pathogenesis.The aim of this work was to isolate new factors that bind to CUG repeats. Using an affinity chromatography strategy with an RNA containing 95 pure CUG repeats, we identified the RNA helicase p68 (DDX5). p68 is a prototype of DEAD-box RNA helicase proteins. This family is characterized by a conserved core, consisting of nine conserved motifs including the DEAD signature, which gives rise to the name to these proteins. p68 is involved in many aspects of RNA metabolism including transcription, RNA processing, RNA export, translation and mRNA degradation. We showed that p68 colocalized with RNA foci in cells expressing the 3’UTR of the DMPK gene containing expanded CTG repeats. We found that p68 increased MBNL1 binding onto pathological repeats and the stem-loop structure regulatory element within the cardiac Troponin T (TNNT2) pre-mRNA, splicing of which is misregulated in DM1. Mutations in the helicase core of p68 prevented both the stimulatory effect of the protein on MBNL1 binding and the colocalization of p68 with CUG repeats, suggesting that remodeling of RNA secondary structure through a ATP-dependant manner by p68 facilitates MBNL1 binding. We also found that the competence of p68 for regulating TNNT2 exon 5 inclusion depended on the integrity of MBNL1 binding sites.We propose that p68 acts as a modifier of MBNL1 activity on splicing targets and pathogenic RNA.

<p>Exoner är de sekvenser i DNA vilka rymmer koden för proteiner i människan och i alla andra organismer. Intronerna, vilka utgör utrymmet mellan exoner, består av ickekodande sekvenser och kontrollelement. Exoner tillhörande en gen måste inte alltid inkluderas i den slutliga mRNA produkten, alternativ splicing tillåter exkludering av vissa sekvenser och gör att en gen kan ha mer än en mRNA produkt, därigenom kan en gen koda för flera olika proteiner. Alternativ splicing är ett fält som snabbt utvecklas och dess relevans för många sjukdomar har blivit uppenbar. Detta arbete går igenom ett flertal av dessa sjukdomar för att sammanställa ny forskning och tydliggöra rollen av alternativ splicing i dem. De sjukdomar som undersökts är cystisk fibros, ärftlig frontotemporal dementia, systemisk lupus erythematosus, aniridi, myotonisk dystrofi, amyotrophic lateral sclerosoch familial dysautonomia. Dessa sjukdomar har involvering av alternativ splicing, de genetiska processerna bakom dem är dock mycket olika och kan visa på de många sätt alternativ splicing kan påverka cell och kroppsfunktion. Målet med arbetet är en översiktlig bild av framstegen som gjorts och vilken forskning som nu bedrivs.</p>

Exoner är de sekvenser i DNA vilka rymmer koden för proteiner i människan och i alla andra organismer. Intronerna, vilka utgör utrymmet mellan exoner, består av ickekodande sekvenser och kontrollelement. Exoner tillhörande en gen måste inte alltid inkluderas i den slutliga mRNA produkten, alternativ splicing tillåter exkludering av vissa sekvenser och gör att en gen kan ha mer än en mRNA produkt, därigenom kan en gen koda för flera olika proteiner. Alternativ splicing är ett fält som snabbt utvecklas och dess relevans för många sjukdomar har blivit uppenbar. Detta arbete går igenom ett flertal av dessa sjukdomar för att sammanställa ny forskning och tydliggöra rollen av alternativ splicing i dem. De sjukdomar som undersökts är cystisk fibros, ärftlig frontotemporal dementia, systemisk lupus erythematosus, aniridi, myotonisk dystrofi, amyotrophic lateral sclerosoch familial dysautonomia. Dessa sjukdomar har involvering av alternativ splicing, de genetiska processerna bakom dem är dock mycket olika och kan visa på de många sätt alternativ splicing kan påverka cell och kroppsfunktion. Målet med arbetet är en översiktlig bild av framstegen som gjorts och vilken forskning som nu bedrivs.