Plants employ sophisticated molecular machineries to fine-tune their responses to growth, developmental, and stress cues. Plants cellular response influences gene expression through regulating processes like transcription and splicing. To increase the genome coding potential and further regulate the expression, pre-mRNA is alternatively spliced. Serine/Arginine-rich (SR) proteins, a family of pre-mRNA splicing factors, recognize splicing cis-elements and regulate both constitutive and alternative splicing. Recent studies reported only 22 SR proteins encoded in the genome of rice (Oryza sativa), which are classified into 6 subfamilies. Oryza s. SC subfamily 106 kDa (Os-Sc106) locus is homologous to the human SR protein SFSR11 (SRp54). Os-Sc106 contains SR proteins characteristics, and was not included among the rice SR proteins. The clustered regularly interspaced short palindromic repeats (CRISPR) and its associated protein 9 (Cas9) system, an RNA-guided endonuclease complex that introduces a double-strand break (DSB) into the DNA. Innovative scientific advances in genome engineering have made CRISPR/Cas9 an excellent system to conduct functional knockout studies of genes in most biological systems including plants. In this study, I targeted the rice Os-Sc106 locus at exon1, and 3 via CRISPR/Cas9 system. Genotyping analyses revealed the recovery of Os-Sc106 mutants including complete functional knockouts such as sf11h-2, sf11h-8, and sf11h-55. Phenotypic analyses show that Os-Sc106 mutants (sf11h-2, 8, 55, and 57) are oversensitive under abiotic stress in comparison to WT plants, suggesting that Os-Sc106 locus encodes a protein that is important for regulating plant stress responses.

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Wnt signaling plays important role in many aspects of embryogenesis such as cell proliferation, cell fate specification, cell polarity and organogenesis(Clevers 2006, van Amerongen and Nusse 2009). Wnt ligands have been shown to activate several intra-cellular signaling cascades, including the canonical or Wnt/-catenin dependent pathway and the non-canonical or -catenin independent pathway. Dishevelled (Dvl) occupies a key position at crossroads of all branches of Wnt signaling cascade. To understand, how Dishevelled (Dvl) may channel signaling into the downstream branches, we sought to identify novel effectors for Dishevelled (Dvl) using a yeast-two hybrid screen. In this study, we used the PDZ domain of Dishevelled (Dvl) as a bait and from this screen, we identified a new binding protein of Dishevelled (Dvl)-termed as Custos. To characterize the functional role of Custos in Wnt signaling pathway, we used mammalian cell culture and zebrafish as a model vertebrate organism. We confirmed the interaction between Custos and Dvl using co-immunoprecipation and GST pull-down. Custos also interacted with -catenin in vivo and this interaction was positively regulated by Wnt stimulation. Immunofluorescence experiments in mammalian cells showed that Custos co-localizes with the nuclear envelope marker, lamin and inhibits translocation of -catenin to the nucleus. In zebrafish embryos, Custos is a maternal gene and expressed throughout development. Spatial in situ hybridization studies showed that Custos was expressed in the dorsal region of the embryo at early stages and in the nervous system in zebrafish at 24hpf. To delineate the biological role of Custos during embryogenesis, we conducted a gain of function and loss of function studies. Overexpression of exogenous Custos and morpholino knockdown of Custos revealed that Custos is critical for embryonic patterning. Knockout of Custos in zebrafish revealed that Custos delays embryonic development and exhibits defects in pigmentation suggesting a plausible role in neural crest development. Taken together, our studies demonstrate that Custos is a novel component of canonical Wnt signaling and required for -catenin translocation into the nucleus and important for embryonic patterning. / Biology

京都大学 / 新制・課程博士 / 博士(農学) / 甲第23521号 / 農博第2468号 / 新制||農||1087(附属図書館) / 学位論文||R3||N5352(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 本田 与一, 教授 田中 千尋, 准教授 坂本 正弘 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

The pig has similar features to the human in aspects such as physiology, immunology, and organ size. Because of these similarities, genetically modified pigs have been generated for xenotransplantation. Also, when using the pig as a model for human diseases (e.g. cystic fibrosis transmembrane conductance regulator), the pig exhibited similar symptoms to those that human patients present. The main goal of this work was to examine the efficacy of direct injection of the CRISPR/Cas9 system (clustered regularly interspaced short palindromic repeats/ CRISPR associated protein 9) in pigs and to overcome shortcomings that resulted after direct injection into the cytoplasm of developing zygotes. By using direct injection of CRISPR/Cas9 into developing zygotes, we successfully generated fetuses and piglets containing 9 different mutations. The total number of aborted fetuses was 20 and of live piglets was 55. Moreover, one issue that was encountered during the production of mutated pigs was that insertion or deletion (indel) mutations did not always introduce a premature stop codon because it did not interfere with the codon read. As a result of these triplet indel(s) mutations, a hypomorphic phenotype was presented; consequently, the mutated gene was partially functional. To prevent this hypomorphic phenotype, we introduced two sgRNAs to generate an intended deletion that would remove a DNA fragment on the genome by causing two double-strand breaks (DSB) during non-homologous end joining (NHEJ). The injection of two sgRNAs successfully generated the intended deletion on the targeted genes in embryos and live piglets. Results after using intended deletions, in IL2RG mutation pigs, did not show hypomorphic phenotypes even when a premature stop codon was not present. After using the intended deletion approach, function of the targeted genes was completely disrupted regardless of the presence or absence of a premature stop codon. Our next aim was to introduce (i.e. knock-in) a portion of exogenous (donor) DNA sequence into a specific locus by utilizing the homology direct repair (HDR) pathway. Because of the cytotoxicity of the linear form of the donor DNA, the concentration of the injected donor DNA was adjusted. After concentration optimization, four different donor DNA fragments targeting four different genes were injected into zygotes. Efficiency of knock-in was an average of 35%. Another donor DNA was used in this study which is IL2RG-IA donor DNA carried 3kb of exogenous cassette. It showed 15.6% of knock-in efficiency. IL2RG-IA Donor DNA injected embryos were transferred into surrogates, and a total of 7 pigs were born from one surrogate, but none of the 7 were positive for the knock-in. Future experiments need to be developed to optimize this approach. Overall, the direct injection of CRISPR/Cas9 is advantageous in cost, time, and efficiency for large animal production and for biomedical research. However, there are still unsolved challenges (off-targeting effects, low efficiency of knock-in, and monoallelic target mutation) that need to be elucidated for future application in humans and other species. / Doctor of Philosophy / The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9) system is commonly used to make genetically modified pigs. The CRISPR/Cas9 system can break the DNA on a desired gene region. During the DNA repair process, random DNA base pairs can be inserted or deleted on the broken regions, thus generating a mutation on the desired gene. Scientists have adopted new methods to disrupt genes in many species. One of these new methods is the direct injection of CRISPR/Cas9 into a fertilized oocyte. In our first project, we used direct injection of the CRISPR/Cas9 system into the fertilized one-cell embryo. A total of 55 live pigs and aborted 20 fetuses with specifically disrupted genes were produced for biomedical research model. During these studies, one critical drawback of the direct injection method was encountered. Partial function of the gene was possible. To prevent this problem, two DNA broken regions were generated by the CRISPR/Cas9 system to remove the middle part the DNA by two DNA breaking. This method successfully removed the middle portion of the DNA targeted region in the pig embryos. Embryos injected with the CRISPR/Cas9 system to cut the two specific DNA regions were transplanted into surrogate pigs, and a total of 15 piglets were produced. All 15 pigs confirmed that a specific part of the gene had been removed by two DNA breakage. Also, no function of the desired gene was found in the 15 pigs. The objective of the last experiment was to introduce a specific exogenous DNA sequences into specific region of DNA using the CRISPR/Cas9 system. For this study, four different exogenous DNA fragments were synthesized for four different genes. When injected, one exogenous DNA along with the CRISPR/Cas9 system, the average integration efficiency of the four exogenous DNA fragments was 35% in the embryo. Another exogenous DNA, which was longer than other four DNA fragments showed 15.6% integration efficiency. The embryos injected with the long exogenous DNA fragment, along with the CRISPR/Cas9 system, were transferred into surrogate pigs. The result was that a total of 7 piglets were born, but the exogenous DNA sequence was not found in none of the seven piglets. In conclusion, the CRISPR/Cas9 system showed effective removal of the entire gene function of specific genes in the pig. However, for future application in the human and other species, some problems (un-wanted region mutation and low efficiency of exogenous DNA integration) continue to emerge and need to be addressed in future experiments.

Tesis por compendio / [ES] El síndrome de Usher (USH) es un trastorno raro autosómico recesivo definido principalmente por sordera neurosensorial (SNHL), y una distrofia retiniana conocida como retinosis pigmentaria (RP). La patología muestra heterogeneidad genética, puesto que se conocen al menos 10 genes responsables. No obstante, las mutaciones en USH2A son la causa más frecuente de la enfermedad, en gran medida por la recurrencia de la variante patogénica c.2299delG. En esta tesis se ha desarrollado un ensayo de edición génica para revertir dicha anomalía genética por medio del sistema CRISPR/Cas9. Se diseñaron y probaron varios complejos CRISPR específicos de locus, y el más eficiente fue usado para la corrección de la mutación c.2299delG en células derivadas de pacientes. La tasa de corrección de la mutación obtenida fue del 2.5%. Otro objetivo de esta tesis ha sido la caracterización genética de pacientes USH aún sin diagnóstico molecular. Una primera fase implicó la secuenciación masiva dirigida de las regiones codificantes de todos los genes asociados a la enfermedad. Este estudio, cuya cohorte incluyó 58 pacientes no escrutados previamente, permitió la identificación de 42 nuevas mutaciones presuntamente patológicas, y una tasa general de detección de alelos responsables de la enfermedad de prácticamente el 83%. Sorprendentemente, uno de los sujetos presentaba mutaciones en CEP250, uno de los últimos genes correlacionados con la enfermedad. Una exhaustiva revisión clínica reveló que la degeneración retiniana se trataba en realidad de una distrofia de conos y bastones en lugar de RP clásica, lo cual permitió consolidación del gen CEP250 como responsable de un fenotipo similar al USH. El resto de casos sin resolver induce a sospechar de la existencia de otros genes vinculados con USH. Así pues, se analizó el exoma íntegro de dichos casos negativos del panel por medio de secuenciación de exoma completo, lo cual proporcionó resultados relevantes en seis de las muestras estudiadas. Uno de tales sujetos resultó ser un claro caso de fenocopia de USH, al albergar mutaciones patogénicas en dos genes independientes, TECTA y REEP6, siendo el primero responsable de la SNHL y el segundo de la RP. De forma parecida, en otro paciente se detectaron variantes patológicas para RP en el gen EYS, pero no se identificó paralelamente ningún cambio genético que explicara la SNHL. Tres individuos adicionales resultaron haber sido erróneamente diagnosticados como USH, dada la conclusiva inexistencia o ambigüedad de la sordera. Uno de ellos fue definido como homocigoto de una mutación en CNGB1, ya reconocido como responsable de RP. En el segundo de dichos sujetos se identificó una mutación en homocigosis en el gen GRN, cuyos defectos en estado heterocigoto están asociados a demencia frontotemporal y más raramente combinada con RP si ambos alelos se encuentran alterados. Por otro lado, el tercer paciente fue resuelto como heterocigoto compuesto de variantes en WDR19, un gen asociado en mayor medida a una distrofia retiniana acompañada de trastornos renales y, más raramente, a la forma aislada del síntoma. En el último de los seis casos resaltados de este objetivo se detectó una mutación homocigota sin sentido en el gen ASIC5, cuyo papel en el organismo todavía se desconoce. Sin embargo, se han correlacionado funciones visuales y auditivas para miembros de la misma familia proteica. En conjunto, los hallazgos obtenidos en este trabajo avalan la importancia del uso de las más novedosas tecnologías en la búsqueda de soluciones para enfermedades raras, las cuales presentan por ahora un pronóstico terapéutico bastante desamparado. Asimismo, otras consecuencias positivas en cuanto a la caracterización genética de los pacientes son la corroboración (o rectificación) del diagnóstico inicial, así como la contribución a la estimación demográfica y correlaciones de genotipo-fenotipo, que en definit / [CA] La síndrome d'Usher (USH) és una malaltia rara autosòmic recessiu definit principalment per sordera neurosensorial (SNHL) i una distròfia retiniana coneguda com a retinosi pigmentària (RP). La patologia mostra heterogeneïtat genètica, ja que es coneixen almenys 10 gens responsables. No obstant això, les mutacions en USH2A són la causa més freqüent de la malaltia, a causa de la recurrència de la variant patogènica c.2299delG. En aquesta tesi s'ha desenvolupat un assaig d'edició gènica per a revertir la dita anomalia genètica per mitjà del sistema CRISPR/Cas9. Es van dissenyar i van probar diversos complexos CRISPR específics de locus, i el més eficient va ser usat per a la correcció de la mutació en cèl·lules derivades de pacients. La taxa de correcció de la mutació obtinguda va ser del 2.5%. Un altre objectiu d'aquesta tesi ha sigut la caracterització genètica de pacients USH encara sense diagnòstic molecular. Una primera fase va implicar la seqüenciació massiva dirigida de les regions codificants de tots els gens associats a la malaltia. Aquest estudi, la cohort de la qual va incloure 58 pacients no escrutats prèviament, va permetre la identificació de 42 noves mutacions presumptament patològiques, i una taxa general de detecció d'al·lels responsables de la malaltia de pràcticament el 83%. Sorprenentment, un dels subjectes presentava mutacions en CEP250, un dels últims gens correlacionats amb la malaltia. Una exhaustiva revisió clínica va revelar que la degeneració retiniana es tractava en realitat d'una distròfia de cons i bastons en lloc de RP clàssica. Aquestes troballes han permés la consolidació del gen CEP250 com a responsable d'un fenotip similar al USH. La resta de casos sense resoldre induïx a sospitar de l'existència d'altres gens vinculats amb USH. Així, doncs, es va analitzar l'exoma íntegre dels casos negatius del panell a través de seqüenciació d'exoma complet, cosa que va proporcionar resultats rellevants en sis de les mostres estudiades. Un de tals subjectes va resultar ser un clar cas de fenocopia d'USH, a l'albergar mutacions patogèniques en dos gens independents, TECTA i REEP6, sent el primer responsable de la SNHL i el segon de la RP. De forma semblant, en un altre pacient es van detectar variants patològiques per a RP al gen EYS, però no es va identificar paral·lelament cap canvi genètic que explicara la SNHL. Tres individus addicionals van resultar haver sigut erròniament diagnosticats com USH, donada la final inexistència o ambigüitat de la sordera. Un d'ells va ser definit com a homozigot d'una mutació en CNGB1, ja reconegut com a responsable de RP. En el segon d'aquestes subjectes es va identificar una mutació en homozigosi en el gen GRN, els defectes del qual estan associats a demència frontotemporal en estat heterozigot, i més rarament en combinació amb RP si ambdós al·lels es troben alterats. D'altra banda, el tercer pacient va ser resolt com a heterozigot compost de variants en WDR19, un gen associat en major grau a una distròfia retiniana acompanyada de trastorns renals i, més rarament, a la forma aïllada del símptoma. En l'últim dels sis casos ressaltats d'aquest objectiu es va detectar una mutació homozigota sense sentit en el gen ASIC5, el paper en l'organisme del qual encara es desconeix. Amb tot, s'han correlacionat funcions visuals i auditives per a membres de la mateixa família proteica. En conjunt, les troballes obtingudes en aquest treball avalen la importància de l'ús de les més noves tecnologies en la recerca de solucions per a malalties rares, les quals presenten per ara un pronòstic terapèutic prou desemparat. Així mateix, altres conseqüències positives quant a la caracterització genètica dels pacients són la corroboració (o rectificació) del diagnòstic inicial, així com la contribució a l'estimació demogràfica i correlacions de genotip-fenotip, que en definitiva ajuden en la compressió d'US / [EN] Usher syndrome (USH) is a rare autosomal recessive disorder defined essentially by sensorineural hearing loss (SNHL) and a retinal dystrophy known as retinitis pigmentosa (RP). The condition shows a genetic heterogeneity, since there are at least 10 genes known to be causative of the syndrome. However, mutations in USH2A are the most frequent cause of the disease, due in a large measure to the recurrence of the c.2299delG pathogenic variant. A gene editing assay to reverse this specific genetic anomaly was developed in this thesis by means of the groundbreaking CRISPR/Cas9 system. Several locus-specific CRISPR complexes were designed and tested, and the most efficient was used to proceed with the c.2299delG mutation correction on patient-derived cells. The trial resulted in a mutation correction rate of 2.5%. Another goal of this thesis was the genetic characterization of molecularly undiagnosed USH patients. Given the genetic diversity of the disease, the procedure required the implementation of high-throughput sequencing, a technology that enables in bulk sequencing of any number of selected loci (or the indiscriminate totality) of the genome. The first phase implied the targeted sequencing of the coding-relevant regions of all known causative or disease-associated genes at the moment. The study, comprising a cohort of 58 previously unscreened patients, enabled the identification of 42 novel putative pathogenic mutations, and an etiologic-allele detection ratio shy of 83%. Remarkably, one of the subjects harbored nonsense mutations in CEP250, which is one of the latest USH-associated genes. However, an exhaustive review of the clinical features unmasked the retinal degeneration as a cone-rod dystrophy rather than RP, which reinforced the linkage of the gene to an USH-like phenotype. The remaining portion of unresolved cases lead to suspicion of the existence of other genes accountable for USH. Hence, the complete exome of such panel-negative cases was screened through whole exome sequencing. This venture provided relevant findings in six of the surveyed samples. One subject was plainly exposed as an USH phenocopy by harboring pathogenic splice-site mutations in two independent genes, TECTA and REEP6, the former responsible for the SNHL and the latter for the RP. Similarly, RP-causative variants in EYS were detected in another patient, yet no pathogenic changes explaining the HL were discovered. Three additional individuals were ultimately unveiled as USH misdiagnosed cases, being the HL actually absent or ambiguous. One of the patients in this set was homozygous for a mutation in CNGB1, already known to be accountable for RP. The other two cases showed a more peculiar outcome being compound heterozygous for putatively pathogenic variants in genes generally associated to other disorders. One presented a homozygous mutation in GRN, a gene associated to frontotemporal dementia under heterozygous condition and less commonly to combined RP for homozygous alterations. The third subject was found to be a carrier of mutations in WDR19, a gene best associated with retinal disorders accompanied by renal signs and rarely with the isolated visual symptom. The last case presented a homozygous nonsense variant in the ASIC5 gene, whose role has yet to be learned. However, some correlations to visual and hearing functions have been reported for members of the same protein family. Altogether, the results obtained from this work attest to the importance of applying the most up-to-date technologies in the search of solutions for rare diseases that realistically pose a despairing therapeutic prognosis. In addition, the positive consequences of the genetic characterization of the patients are the corroboration (or else correction) of the initial diagnosis, and the contribution to the appraisal of demographic and genotype-phenotype correlations, which ultimately aid in the understanding USH and other related diseases. / This work was financially supported by the Institute of Health Carlos III and FEDER funds (ISCIII; grants PI13/00638, PI16/00425, PI16/00539, and PIE13/00046), Fundación ONCE (grant 2015/0398), XVIII Fundaluce-FARPE, and “Telemaratón: Todos Somos Raros, Todos Somos Únicos” (grant IP58). C.F.-G. is a recipient of a fellowship (grant IFI14/00021) from the ISCIII. R.P.V.-M. is a Miguel Servet researcher (grant CP11/00090 funded by ISCIII, Madrid, Spain). The funds from the ISCIII are partially supported by the European Regional Development Fund. R.-P.V.M. is also a Marie Curie fellow (grant CIG322034 from the European Commission). / Fuster García, C. (2020). Therapeutic approaches and development of genomic diagnostic tools for Usher syndrome [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/137034 / Compendio

Targeted gene manipulation in a complex microbial community is an enabling technology for precise microbiome editing. This thesis introduces a new microbial therapeutic system dubbed Bacterial CRISPR-Transposase Reduction of Virulence In Situ (BACTRINS). BACTRINS is an in-situ microbiome engineering platform designed for efficient and precise genomic insertion of a desired payload and simultaneous knockout of target genes. When applied against a Shiga toxin-producing pathogen in the gut, this system delivers a CRISPR-associated transposase by bacterial conjugation for site-specific inactivation of the Shiga toxin gene and integration of a nanobody therapeutic payload to disrupt pathogen attachment. A single dose of this therapy resulted in high efficiency Shiga gene inactivation and improved survival in a murine infection model of Shiga-producing pathogen. This work establishes a new type of live bacterial therapeutic capable of reducing gut infections by transforming toxigenic pathogens into commensal protectors.