Drag på parnassen. Två sextiotalsstudier. : Del I: Medelklass med mänskligt ansikte. Medelklassradikalism i fyra romaner av Christer Kihlman, Jarl Sjöblom, Marianne Alopaeus och Ulla-Lena Lundberg. Del II: Modernistdebatten. Sak, person och fält i en finlandssvensk litteraturdebatt år 1965.

The objective of my dissertation Pull (or Draught, or Moves) at the Parnassus , is to provide a deeper understanding of Nordic Middle Class radicalism of the 1960 s as featured in Finland-Swedish literature. My approach is cultural materialist in a broad sense; social class is regarded a crucial aspect of the contents and contexts of the novels and literary discussions explored. In the first volume, Middle Class With A Human Face , novels by Christer Kihlman, Jarl Sjöblom, Marianne Alopaeus, and Ulla-Lena Lundberg, respectively, are read from the points of view of place, emotion, and power. The term "cryptotope" is used to designate the hidden places found to play an important role in all of these four narratives. Also, the "chronotope of the provincial small town", described by Mikhail Bakhtin in 1938, is exemplified in Kihlman s satirical novel, as is the chronotope of of war (Algeria, Vietnam) in those of Alopaeus and Lundberg s. All the four novels signal changes in the way general "scripts of emotions", e.g. jealousy, are handled and described. The power relations in the novels are also read, with reference to Michel Foucault. As the protagonists in two of them work as journalists, a critical discussion about media and Bourgeois hegemony is found; the term "repressive legitimation" is created to grasp these patterns of manipulation. The Modernist Debate , part II of the study, concerns a literary discussion between mainly Finland-Swedish authors and critics. Essayist Johannes Salminen (40) provided much of the fuel for the debate in 1963, questioning the relevance to contemporary life of the Finland-Swedish modernist tradition of the 1910 s and 1920 s. In 1965, a group of younger authors and critics, including poet Claes Andersson (28), followed up this critique in a debate taking place mainly in the newspaper Vasabladet. Poets Rabbe Enckell (62), Bo Carpelan (39) and others defended a timeless poetry. This debate is contextualized and the changing literary field is analyzed using concepts provided by sociologist Pierre Bourdieu. In the thesis, the historical moment of Middle Class radicalism with a human face is regarded a temporary luxury that new social groups could afford themselves, as long as they were knocking over the statues and symbols of the Old Bourgeoisie. This is not to say that all components of the Sixties strategy have lost their power. Some of them have survived and even grown, others remain latent in the gene bank of utopias, waiting for new moments of change.

"Han är en trollkarl. Alla skriver laudatur som går på hans lektioner" : en studie om elevernas uppfattningar om orsakerna till toppresultat i svenska i tre finska gymnasier

Tämä pro gradu -tutkielma on tehty osana Svenska i toppen -projektia, joka alkoi syksyllä 2008 Pohjoismaisten kielten ja pohjoismaisen kirjallisuuden laitoksella. Tutkimuksen tavoitteena on selvittää, mitkä tekijät vaikuttavat lukiolaisten näkökulmasta hyvien tulosten saavuttamiseen ruotsin ylioppilaskirjoituksissa kolmessa suomenkielisessä lukiossa, jotka sijaitsevat Turun, Tampereen ja Joensuun seuduilla. Lisäksi tavoitteena on selvittää, miten maantieteelliset tekijät vaikuttavat opiskelijoiden ruotsin kielen osaamiseen sekä mitä eroja on keskipitkän ja pitkän ruotsin oppimäärän opiskelijoiden asenteissa kieltä kohtaan. Tutkielman aineistona on kolme ryhmähaastattelua, joihin on osallistunut 14 lukiolaista, 11 tyttöä ja 3 poikaa. Haastattelut on tehty joulukuussa 2008 sekä tammi- ja maaliskuussa 2009. Haastatteluissa on käytetty strukturoitua kyselylomaketta, jossa kysytään opiskelijoiden näkemyksiä ruotsin opiskelusta. Tutkimusmenetelmänä on kvalitatiivinen tutkimusote, jossa on piirteitä kolmesta eri menetelmästä: tapaustutkimuksesta, etnografisesta tutkimuksesta sekä temaattisesta analyysistä. Tärkeimpänä teoriataustana on ruotsi toisena kielenä -tutkimus, oppiminen sosiokonstruktivistisena ilmiönä sekä motivaatiotutkimus. Tarkastelen kielenoppijaa luokkahuoneessa sosiaalisena osallistujana omassa oppimisprosessissaan. Oppiminen nähdään kokonaisuutena, johon kuuluu eri osa-alueita, esimerkiksi koulujen käytännöt, yhteisön vaikutus oppimiseen sekä opiskelijan identiteetin muokkautuminen kouluyhteisössä. Motivaatiota tarkastelen kielenoppimisen näkökulmasta, ja se koostuu erilaisista dynaamisista vaiheista, esimerkiksi tavoitteiden asettamisesta oppimisprosessin alussa, valintojen tekemisestä sekä motivaation ylläpitämisestä oppimisprosessin kuluessa. Tutkimuksen tulokset osoittavat, että suurin yksittäinen syy menestykseen opiskelijoiden näkökulmasta on opettaja, joka omalla toiminnallaan voi merkittävästi parantaa opiskelijoiden oppimisedellytyksiä. Työhön panostaminen, opiskelijoiden yksilöllinen kohtaaminen myös luokkahuoneen ulkopuolella ja esimerkiksi omien oppimateriaalien valmistaminen ovat opettajaan liittyviä tekijöitä, jotka voivat nostaa opiskelijoiden motivaatiota huomattavasti. Myös lukion maantieteellisellä sijainnilla on vaikutusta. Paikkakunnilla, joilla ruotsin kieltä käytetään vähän, korostuu opettajan rooli kielellisen oppimisympäristön luomisessa. Keskipitkän ja pitkän ruotsin opiskelijoiden välillä ei tutkimuksessa ilmene eroja asenteissa kieltä kohtaan.

Trafficking and ethanol-induced inhibition of AMPA receptors

AMPA receptors are an important class of ionotropic glutamate receptors which participate in fast excitatory synaptic transmission in most brain areas. They have a pivotal role in adjustment of cell membrane excitability as their cell membrane expression levels is altered in brain physiology such as in learning and memory formation. AMPA receptor function and trafficking is regulated by several proteins, such as transmembrane AMPA receptor regulatory proteins (TARPs). NMDA-type glutamate receptors are important target molecules of ethanol. The role of AMPA receptors in the actions of ethanol has not been clarified as thoroughly. Furthermore, the regulation of AMPA receptor synthesis and their possible adaptation in neurons with altered inhibitory mechanisms are poorly understood. In this thesis work AMPA receptor pharmacology, trafficking and synaptic localization was studied using patch-clamp electrophysiology. Both native and recombinant AMPA receptors were studied. Hippocampal slices from transgenic Thy1alfa6 mice with altered inhibition were used to study adaptation of AMPA receptors. Ethanol was found to inhibit AMPA receptor function by increasing desensitization of the receptor, as the steady-state current was inhibited more than the peak current. Ethanol inhibition was reduced when cyclothiazide was used to block desensitization and when non-desensitizing mutant receptors were studied. Ethanol also increased the rate of desensitization, which was increased further by the coexpression of TARP-proteins. We found that the agonist binding capability is important for trafficking AMPA receptors from endoplasmic reticulum to the cell membrane. TARP rescues the surface expression of non-binding AMPA receptor mutants in HEK293 cells, but not in native neurons. Studies with Thy1alfa6 mice revealed that decreased inhibition decrease AMPA receptor mediated excitation keeping the neurotransmission in balance. Thy1alfa6 mice also had lower sensitivity to electroshock convulsions, presumably due to the decreased AMPA receptor function. The results suggest that during alcohol intoxication ethanol may inhibit AMPA receptors by increasing the rate and the extent of desensitization. TARPs appear to enhance ethanol inhibition. TARPs also participate in trafficking of AMPA receptors upon their synthesis in the cell. AMPA receptors mediate also long-term adaptation to altered neuronal excitability, which adds to their well-known role in synaptic plasticity.

The Mechanisms of Hedgehog Signal Transduction

Studies in both vertebrates and invertebrates have identified proteins of the Hedgehog (Hh) family of secreted signaling molecules as key organizers of tissue patterning. Initially discovered in Drosophila in 1992, Hh family members have been discovered in animals with body plans as diverse as those of mammals, insects and echinoderms. In humans three related Hh genes have been identified: Sonic, Indian and Desert hedgehog (Shh, Ihh and Dhh). Transduction of the Hh signal to the cytoplasm utilizes an unusual mechanism involving consecutive repressive interactions between Hh and its receptor components, Patched (Ptc) and Smoothened (Smo). Several cytoplasmic proteins involved in Hh signal transduction are known in Drosophila, but mammalian homologs are known only for the Cubitus interruptus (Ci) transcription factor (GLI(1-3)) and for the Ci/GLI-associated protein, Suppressor of Fused (Su(fu)). In this study I analyzed the mechanisms of how the Hh receptor Ptc regulates the signal transducer Smo, and how Smo relays the Shh signal from the cell surface to the cytoplasm ultimately leading to the activation of GLI transcription factors. In Drosophila, the kinesin-like protein Costal2 (Cos2) is required for suppression of Hh target gene expression in the absence of ligand, and loss of Cos2 causes embryonic lethality. Cos2 acts by bridging Smo to the Ci. Another protein, Su(Fu) exerts a weak suppressive influence on Ci activity and loss of Su(Fu) causes subtle changes in Drosophila wing pattern. This study revealed that domains in Smo that are critical for Cos2 binding in Drosophila are dispensable for mammalian Smo function. Furthermore, by analyzing the function of Su(Fu) and the closest mouse homologs of Cos2 by protein overexpression and RNA interference I found that inhibition of the Hh response pathway in the absence of ligand does not require Cos2 activity, but instead critically depends on the activity of Su(Fu). These results indicate that a major change in the mechanism of action of a conserved signaling pathway occurred during evolution, probably through phenotypic drift made possible by the existence in some species of two parallel pathways acting between the Hh receptor and the Ci/GLI transcription factors. In a second approach to unravel Hh signaling we cloned > 90% of all human full-length protein kinase cDNAs and constructed the corresponding kinase-activity deficient mutants. Using this kinome resource as a screening tool, two kinases, MAP3K10 and DYRK2 were found to regulate Shh signaling. DYRK2 directly phosphorylated and induced the proteasome dependent degradation of the key Hh-pathway regulated transcription factor, GLI2. MAP3K10, in turn, affected GLI2 indirectly by modulating the activity of DYRK2.

The function of Bmps and Runx2 in normal tooth development and in the pathogenesis of cleidocranial dysplasia

The development of many embryonic organs is regulated by reciprocal and sequential epithelial-mesenchymal interactions. These interactions are mediated by conserved signaling pathways that are reiteratively used. Cleidocranial dysplasia (CCD) is a congenital syndrome where both bone and tooth development is affected. The syndrome is characterized by short stature, abnormal clavicles, general bone dysplasia, and supernumerary teeth. CCD is caused by mutations in RUNX2, a transcription factor that is a key regulator of osteoblast differentiation and bone formation. The first aim of this study was to analyse the expression of a family of key signal molecules, Bone morphogenetic protein (Bmp) at different stages of tooth development. Bmps have a variety of functions and they were originally discovered as signals inducing ectopic bone formation. We performed a comparative in situ hybridisation analysis of the mRNA expression of Bmp2-7 from initiation of tooth development to differentiation of dental hard tissues. The expression patterns indicated that the Bmps signal between the epithelial and mesenchymal tissues during initiation and morphogenesis of tooth development, as well as during the differentiation of odontoblasts and ameloblasts. Furthermore, they are also part of the signalling networks whereby the enamel knot regulates the patterning of tooth cusps. The second aim was to study the role of Runx2 during tooth development and thereby to gain better understanding of the pathogenesis of the tooth phenotype in CCD. We analysed the tooth phenotype of Runx2 knockout mice and examined the patterns and regulation of Runx2 gene expression.. The teeth of wild-type and Runx2 mutant mice were compared by several methods including in situ hybridisation, tissue culture, bead implantation experiments, and epithelial-mesenchymal recombination studies. Phenotypic analysis of Runx2 -/- mutant tooth development showed that teeth failed to advance beyond the bud stage. Runx2 expression was restricted to dental mesenchyme between the bud and early bell stages of tooth development and it was regulated by epithelial signals, in particular Fgfs. We searched for downstream targets of Runx2 by comparative in situ hybridisation analysis. The expression of Fgf3 was downregulated in the mesenchyme of Runx2 -/- teeth. Shh expression was absent from the enamel knot in the lower molars of Runx2 -/- and reduced in the upper molars. In conclusion, these studies showed that Runx2 regulates key epithelial-mesenchymal interactions that control advancing tooth morphogenesis and histodifferentiation of the epithelial enamel organ. In addition, in the upper molars of Runx2 mutants extra buddings occured at the palatal side of the tooth bud. We suggest that Runx2 acts as an inhibitor of successional tooth formation by preventing advancing development of the buds. Accordingly, we propose that RUNX2 haploinsuffiency in humans causes incomplete inhibition of successional tooth formation and as a result supernumerary teeth.

Movement-associated proteins of Potato virus A: attachment to virus particles and phosphorylation

The particles of Potato virus A (PVA; genus Potyvirus) are helically constructed filaments that contain multiple copies of a single type of coat-protein (CP) subunit and a single copy of genome-linked protein (VPg), attached to one end of the virion. Examination of negatively-stained virions by electron microscopy revealed flexuous, rod-shaped particles with no obvious terminal structures. It is known that particles of several filamentous plant viruses incorporate additional minor protein components, forming stable complexes that mediate particle disassembly, movement or transmission by insect vectors. The first objective of this work was to study the interaction of PVA movement-associated proteins with virus particles and how these interactions contribute to the morphology and function of the virus particles. Purified particles of PVA were examined by atomic force microscopy (AFM) and immuno-gold electron microscopy. A protrusion was found at one end of some of the potyvirus particles, associated with the 5' end of the viral RNA. The tip contained two virus-encoded proteins, the genome-linked protein (VPg) and the helper-component proteinase (HC-Pro). Both are required for cell-to-cell movement of the virus. Biochemical and electron microscopy studies of purified PVA samples also revealed the presence of another protein required for cell-to-cell movement the cylindrical inclusion protein (CI), which is also an RNA helicase/ATPase. Centrifugation through a 5-40% sucrose gradient separated virus particles with no detectable CI to a fraction that remained in the gradient, from the CI-associated particles that went to the pellet. Both types of particles were infectious. AFM and translation experiments demonstrated that when the viral CI was not present in the sample, PVA virions had a beads-on-a-string phenotype, and RNA within the virus particles was more accessible to translation. The second objective of this work was to study phosphorylation of PVA movement-associated and structural proteins (CP and VPg) in vitro and, if possible, in vivo. PVA virion structural protein CP is necessary for virus cell-to-cell movement. The tobacco protein kinase CK2 was identified as a kinase phosphorylating PVA CP. A major site of CK2 phosphorylation in PVA CP was identified as a single threonine within a CK2 consensus sequence. Amino acid substitutions affecting the CK2 consensus sequence in CP resulted in viruses that were defective in cell-to-cell and long-distance movement. The CK2 regulation of virion assembly and cell-to-cell movement by phosphorylation of CP was possibly due to the inhibition of CP binding to viral RNA. Four putative phosphorylation sites were identified from an in vitro phosphorylated recombinant VPg. All four were mutated and the spread of mutant viruses in two different host plants was studied. Two putative phosphorylation site mutants (Thr45 and Thr49) had phenotypes identical to that of a wild type (WT) virus infection in both Nicotiana benthamiana and N. tabacum plants. The other two mutant viruses (Thr132/Ser133 and Thr168) showed different phenotypes with increased or decreased accumulation rates, respectively, in inoculated and the first two systemically infected leaves of N. benthamiana. The same mutants were occasionally restricted to single cells in N. tabacum plants, suggesting the importance of these amino acids in the PVA infection cycle in N. tabacum.

Lactic acid bacteria and their antimicrobial peptides : Induction,detection,partial characterization, and potential applications

Bacteriocin-producing lactic acid bacteria and their isolated peptide bacteriocins are of value to control pathogens and spoiling microorganisms in foods and feed. Nisin is the only bacteriocin that is commonly accepted as a food preservative and has a broad spectrum of activity against Gram-positive organisms including spore forming bacteria. In this study nisin induction was studied from two perspectives, induction from inside of the cell and selection of nisin inducible strains with increased nisin induction sensitivity. The results showed that a mutation in the nisin precursor transporter NisT rendered L. lactis incapable of nisin secretion and lead to nisin accumulation inside the cells. Intracellular proteolytic activity could cleave the N-terminal leader peptide of nisin precursor, resulting in active nisin in the cells. Using a nisin sensitive GFP bioassay it could be shown, that the active intracellular nisin could function as an inducer without any detectable release from the cells. The results suggested that nisin can be inserted into the cytoplasmic membrane from inside the cell and activate NisK. This model of two-component regulation may be a general mechanism of how amphiphilic signals activate the histidine kinase sensor and would represent a novel way for a signal transduction pathway to recognize its signal. In addition, nisin induction was studied through the isolation of natural mutants of the GFPuv nisin bioassay strain L. lactis LAC275 using fl uorescence-activated cell sorting (FACS). The isolated mutant strains represent second generation of GFPuv bioassay strains which can allow the detection of nisin at lower levels. The applied aspect of this thesis was focused on the potential of bacteriocins in chicken farming. One aim was to study nisin as a potential growth promoter in chicken feed. Therefore, the lactic acid bacteria of chicken crop and the nisin sensitivity of the isolated strains were tested. It was found that in the crop Lactobacillus reuteri, L. salivarius and L. crispatus were the dominating bacteria and variation in nisin resistance level of these strains was found. This suggested that nisin may be used as growth promoter without wiping out the dominating bacterial species in the crop. As the isolated lactobacilli may serve as bacteria promoting chicken health or reducing zoonoosis and bacteriocin production is one property associated with probiotics, the isolated strains were screened for bacteriocin activity against the pathogen Campylobacter jejuni. The results showed that many of the isolated L. salivarius strains could inhibit the growth of C. jejuni. The bacteriocin of the L. salivarius LAB47 strain, with the strongest activity, was further characterized. Salivaricin 47 is heat-stable and active in pH range 3 to 8, and the molecular mass was estimated to be approximately 3.2 kDa based on tricine SDS-PAGE analysis.

Komplexa tal - vad är det?

Komplexa tal har traditionellt undervisats i de finländska gymnasierna som en valbar kurs. Denna situation har förändrats i och med de nya läroplanerna som tagits i bruk senast hösten 2005. Den nya, striktare läroplanen ger inte lika stora valmöjligheter för skolorna att bestämma undervisningsstoffet, inte ens för de valbara kurserna, och därför har många gymnasier varit tvungna att sluta undervisa om komplexa tal. För att fortsättningsvis ge en möjlighet för gymnasieelever att studera komplexa tal finns detta kompendium. Kompendiet fyller två syften. I de gymnasier där komplexa tal fortfarande finns med i läroplanen kan kompendiet användas som läromedel på ifrågavarande kurs. Kompendiet torde vara önskat eftersom det inte existerar något modernt, finlandssvenskt läromedel där de komplexa talen tas upp. Kompendiets andra, huvudsakliga syfte är att finnas till att ge en möjlighet för de elever, som inte går ett gymnasium där komplexa tal undervisas, att på egen hand lära sig grunder om komplexa tal. Kunskap om utvidgandet av talområdet från reella talen till komplexa hör till matematisk allmänbildning, och är till stor nytta om man är intresserad av att fortsätta studera matematik eller naturvetenskaper efter gymnasiet. Kompendiet kommer att läggas ut på nätet för att få det lättillgängligt. I det första kapitlet behandlas matematikens uppkomst. Det andra kapitlet är en introduktion till varför man behöver komplexa tal, där gås tal- och mängdlära igenom samtidigt som de i kompendiet använda beteckningarna introduceras. I det tredje kapitlet behandlas de komplexa talen; grundläggande räkneregler, absolutbelopp och argument, komplexa tal i polär form och lösning till högregradsekvationer är centrala begrepp. de Moivers formel är ett av de viktigare målen, även Eulers formel behandlas kort. Problematik med negativa kvadratrötter tas också upp. Det fjärde kapitlet handlar om de komplexa talens intressanta historia. I kompendiet finns rikligt med exempel och övningsuppgifter. Kapitel fem innehåller extra övningsuppgifter och i kapitel sex finns lösningarna till samtliga uppgifter. Trots att kompendiets omfång avsevärt ökas i och med dessa lösningar är det av värde att de finns med för att kompendiets huvudsakliga syfte skall uppfyllas: att eleverna på egen hand skall kunna lära sig stoffet.

Eru Ilúvatar : Jumala J.R.R. Tolkienin legendariumissa

The purpose of my research is to inquire into the essence and activity of God in the legendarium of the English philologist and writer J.R.R. Tolkien (1892-1973). The legendarium, composed of Tolkien’s writings related to Middle-earth, was begun when he created two Elvish languages, Quenya based on Finnish, Sindarin based on Welsh. Tolkien developed his mythology inspired by Germanic myths and The Kalevala. It is a fictional ancient history set in our world. The legendarium is monotheistic: God is called Eru ‘The One’ and Ilúvatar ‘Father of All’. Eru is the same as the Christian God, for Tolkien wanted to keep his tales consistent with his faith. He said his works were Christian by nature, with the religious element absorbed into the story and the symbolism. In The Silmarillion, set in the primeval ages of Middle-earth, the theological aspects are more conspicuous, while in The Lord of the Rings, which brings the stories to an end, they are mostly limited to symbolic references. The legendarium is unified by its realistic outlook on creaturely abilities and hope expressing itself as humbly defiant resistance. ”The possibility of complexity or of distinctions in the nature of Eru” is a part of the legendarium. Eru Ilúvatar is Trinitarian, as per Tolkien’s faith. Without contextual qualifiers, Eru seems to refer to God the Father, like God in the Bible. Being the creator who dwells outside the world is attributed to Him. The Holy Spirit is the only Person of the Trinity bestown with names: the Flame Imperishable and the Secret Fire. When Eru creates the material world with His word, He sends the Flame Imperishable to burn at the heart of the world. The Secret Fire signifies the Creative Power that belongs to God alone, and is a part of Him. The Son, the Word, is not directly mentioned, but according to one writing Eru must step inside the world in order to save it from corruption, yet remain outside it at the same time. The inner structure of the legendarium refers to the need for a future salvation. The creative word of Eru, “Eä! Let these things Be!”, probably has a connection with the Logos in Christianity. Thus we can find three “distinctions” in Eru: a Creator who dwells outside the world, a Sustainer who dwells inside it and a Redeemer who shall step inside it. Some studies of Tolkien have claimed that Eru is distant and remote. This seems to hold water only partially. Ilúvatar, the Father of All, has a special relation with the Eruhíni, His Children, the immortal Elves and the mortal Men. He communicates with them directly only through the Valar, who resemble archangels. Nevertheless, only the Children of Eru can fight against evil, because their tragic fortunes turn evil into good. Even though religious activities are scarce among them, the fundamental faith and ultimate hope of the “Free Peoples” is directed towards Eru. He is present in the drama of history as the “Author of the Story”, who at times also interferes with its course through catastrophes and eucatastrophes, ‘good catastrophes’. Eru brings about a catastrophe when evil would otherwise bring good to an end, and He brings about a eucatasrophe when creaturely strength is not sufficent for victory. Victory over corruption is especially connected with mortal Men, of whom the most (or least) insignificant people are the Hobbits. However, because of the “primeval disaster” (that is, fall) of Mankind, ultimate salvation can only remain open, a hope for the far future.

Role of Eda and Troy pathways in ectodermal organ development

Several organs of the embryo develop as appendages of the ectoderm, the outermost layer of the embryo. These organs include hair follicles, teeth and mammary glands, which all develop as a result of reciprocal tissue interactions between the surface epithelium and the underlying mesenchyme. Several signalling molecules regulate ectodermal organogenesis the most important ones being Wnts, fi broblast growth factors (Fgfs), transforming growth factor -βs (Tgf-βs) including bone morphogenetic proteins (Bmps), hedgehogs (Hhs), and tumour necrosis factors (Tnfs). This study focuses on ectodysplasin (EDA), a signalling molecule of the TNF superfamily. The effects of EDA are mediated by its receptor EDAR, an intracellular adapter protein EDARADD, and downstream activation of the transcription factor nuclear factor kappa-B (NF-кB). Mice deficient in Eda (Tabby mice), its receptor Edar (downless mice) or Edaradd (crinkled mice) show identical phenotypes characterised by defective ectodermal organ development. These mouse mutants serve as models for the human syndrome named hypohidrotic ectodermal dysplasia (HED) that is caused by mutations either in Eda, Edar or Edaradd. The purpose of this study was to characterize the ectodermal organ phenotype of transgenic mice overexpressing of Eda (K14-Eda mice), to study the role of Eda in ectodermal organogenesis using both in vivo and in vitro approaches, and to analyze the potential redundancy between the Eda pathway and other Tnf pathways. The results suggest that Eda plays a role during several stages of ectodermal organ development from initiation to differentiation. Eda signalling was shown to regulate the initiation of skin appendage development by promoting appendageal cell fate at the expense of epidermal cell fate. These effects of Eda were shown to be mediated, at least in part, through the transcriptional regulation of genes that antagonized Bmp signalling and stimulated Shh signalling. It was also shown that Eda/Edar signalling functions redundantly with Troy, which encodes a related TNF receptor, during hair development. This work has revealed several novel aspects of the function of the Eda pathway in hair and tooth development, and also suggests a previously unrecognized role for Eda in mammary gland development.