3 research outputs found
A Functional Single-Nucleotide Polymorphism Upstream of the Collagen Type III Gene Is Associated with Catastrophic Fracture Risk in Thoroughbred Horses
Fractures caused by bone overloading are a leading cause of euthanasia in Thoroughbred racehorses. The risk of fatal fracture has been shown to be influenced by both environmental and genetic factors but, to date, no specific genetic mechanisms underpinning fractures have been identified. In this study, we utilised a genome-wide polygenic risk score to establish an in vitro cell system to study bone gene regulation in horses at high and low genetic risk of fracture. Candidate gene expression analysis revealed differential expression of COL3A1 and STAT1 genes in osteoblasts derived from high- and low-risk horses. Whole-genome sequencing of two fracture cases and two control horses revealed a single-nucleotide polymorphism (SNP) upstream of COL3A1 that was confirmed in a larger cohort to be significantly associated with fractures. Bioinformatics tools predicted that this SNP may impact the binding of the transcription factor SOX11. Gene modulation demonstrated SOX11 is upstream of COL3A1, and the region binds to nuclear proteins. Furthermore, luciferase assays demonstrated that the region containing the SNP has promoter activity. However, the specific effect of the SNP depends on the broader genetic background of the cells and suggests other factors may also be involved in regulating COL3A1 expression. In conclusion, we have identified a novel SNP that is significantly associated with fracture risk and provide new insights into the regulation of the COL3A1 gene
Establishing a safe harbor site for the introduction of genetic information in the human cells by the recombination system attP/attB
[eng] The goal of this project is to generate a safe harbor site in the genome of human
cells, where information could be specifically inserted without the action of
nucleases. The mechanism that we present here is based on two different sitespecific
recombinases phiC31 and Bxb1, as well as on the piggyBack and Sleeping
Beauty transposons. Recombinase phiC31 is an integrase used by phages to establish
the lysogenic life cycle. During integration, phiC31 drives recombination between the
attP and the attB attachment sites on the phage and host genome, respectively. In
naturally occurring phage infestations, the end result is an integrated phage genome
flanked by new attL and attR sites, generated by recombination of the original, attP
and attB sites. In our system, the phage genome is substituted by the acceptor sites
that will constitute the core of the safe harbor locus. Under inducing conditions, the
phage genome is excised via integrase-mediated recombination between attL and
attR regenerating the attP and attB attachment sites. This action is directed by
PhiC31 in the presence of an accessory protein (the recombination directionality
factor, RDF). The alternative use of phiC31, alone or together with RDF, allows for the
indefinite repetition of the cycle and the subsequent incorporation into the targeted
locus of as many attachment sites as needed. The whole mechanism is made possible
by the coordinated and alternative use of piggyBac and Sleeping Beauty transposons
that, at each step, remove residual DNA fragments (plasmid sequences, selection
elements, etc.). Once the final configuration of the safe harbor locus is reached, the
Bxb1 recombinase is used to upload the desired genetic information: markers,
therapeutic genes, inducible system or even complete regulatory routes.[spa] El objetivo principal de este proyecto es generar una plataforma de carga segura
dentro del genoma de c茅lulas humanas, donde la informaci贸n pueda ser insertada de
forma espec铆fica sin la necesidad de usar nucleasas. De este modo se reducir铆a la
posibilidad de integraciones azarosas y se aumentar铆a la eficiencia de integraci贸n.
Para este fin, el mecanismo propuesto en la presente Tesis Doctoral combina el uso
de dos recombinasas diferentes, phiC31 y Bxb1, as铆 como de los sistemas de
transposici贸n piggyBac y Sleeping Beauty. La recombinasa phiC31 es una integrasa
encargada de la incorporaci贸n del ADN de fagos en el hospedador durante el ciclo
lisog茅nico. La integraci贸n se realiza mediante recombinaci贸n entre dos sitios de
uni贸n espec铆ficos, attP presente en el fago y attB localizado en el genoma del
hospedador. Durante el proceso de infecci贸n el genoma del fago queda integrado en
el genoma del hospedador y flanqueado por dos nuevos sitios de reconocimiento
espec铆fico, attL y attR, generados a partir de la recombinaci贸n de las secuencias
originales, attP y attB. En nuestro sistema, el genoma del fago es sustituido por los
sitios de carga que constituir谩n el n煤cleo de la plataforma de integraci贸n. Bajo
condiciones de inducci贸n el genoma del fago puede eliminarse del sitio de
integraci贸n mediante recombinaci贸n entre los sitios attL y attR, regener谩ndose en el
proceso los sitios attB y attP originales. Esta reacci贸n inversa la cataliza phiC31 en
presencia de una prote铆na accesoria denominada Factor de Direccionalidad de la
Recombinaci贸n (RDF, por sus siglas en ingl茅s). El uso alternativo de phiC31 sola o en
combinaci贸n con RDF, hace posible la repetici贸n indefinida del ciclo de carga y la
consiguiente incorporaci贸n al locus gen贸mico elegido de tantos sitios de
recombinaci贸n como se consideren necesarios. El ensamblaje completo de la
plataforma se consigue mediante el uso coordinado y alternativo de los transposones
piggyBac y Sleeping Beauty que permite en cada paso la eliminaci贸n de los
fragmentos de ADN no deseados (secuencias del pl谩smido, elementos de selecci贸n,
etc.). Una vez constituida la plataforma de carga, la recombinasa Bxb1 es la
responsable de mediar la carga de la informaci贸n gen茅tica deseada: marcadores,
genes terap茅uticos, sistema inducible o incluso rutas regulatorias completas.[cat] L鈥檕bjectiu principal d鈥檃quest projecte 茅s generar una plataforma de c脿rrega segura
dins el genoma, en c猫l路lules humanes, on la informaci贸 pugui ser inserida de manera
espec铆fica i sense necessitat d鈥檜sar nucleases. D鈥檃questa manera es reduiria la
possibilitat d鈥檌ntegracions degudes a l鈥檃tzar i s鈥檃ugmentaria l鈥檈fici猫ncia d鈥檌ntegraci贸.
Amb aquest finalitat, el mecanisme proposat en la present Tesi doctoral combina l鈥櫭簊
de dues recombinases diferents, phiC31 i Bxb1, aix铆 com dels transposons piggyBac i
Sleeping Beauty. La recombinasa phiC31 茅s una integrasa encarregada de la
incorporaci贸 de l鈥橝DN de fags a l鈥檋oste durant el cicle lisog猫nic. Aquesta integraci贸 es
realitza mitjan莽ant la recombinaci贸 entre dos llocs d鈥檜ni贸 espec铆fics, attP present en
el fag i attB localitzat en el genoma de l鈥檋oste. Durant el proc茅s d鈥檌nfecci贸 el genoma
del fag queda integrat en el genoma de l鈥檋oste i flanquejat per dos llocs de
reconeixement espec铆fic nous, attL i attR, generats a partir de la recombinaci贸 de les
seq眉猫ncies originals, attP i attB. En el nostre sistema, el genoma del fag 茅s substitu茂t
pels llocs de c脿rrega que constituiran el nucli de la plataforma d'integraci贸. Sota
condicions d'inducci贸 el genoma del fag pot eliminar del lloc d'integraci贸 mitjan莽ant
recombinaci贸 entre els llocs attL i attr, regenerant-se en el proc茅s els llocs attB i attP
originals. Aquesta reacci贸 inversa la catalitza phiC31 en pres猫ncia d'una prote茂na
access貌ria anomenada Factor de Direccionalitat de la Recombinaci贸 (RDF, per les
sigles en angl猫s). L'煤s alternatiu de phiC31 sola o en combinaci贸 amb RDF, fa possible
la repetici贸 indefinida del cicle de c脿rrega i la conseg眉ent incorporaci贸 al locus
gen貌mic triat de tants llocs de recombinaci贸 com es considerin necessaris.
L'acoblament complet de la plataforma s'aconsegueix mitjan莽ant l'煤s coordinat i
alternatiu dels transposons piggyBac i Sleeping Beauty que permet a cada pas
l'eliminaci贸 dels fragments d'ADN no desitjats (seq眉猫ncies del pl脿smid, elements de
selecci贸, etc.). Un cop constitu茂da la plataforma de c脿rrega, la recombinasa Bxb1 茅s
emprada per a la c脿rrega d'informaci贸 gen猫tica desitjada: marcadors, gens
terap猫utics, sistemes indu茂ble o incl煤s rutes reguladores completes