Biology subjects

Ordonez, J. L.

Publications and source records attributed to Ordonez, J. L..

3 recordsLinked to original sources

bioRxiv2024

Differential expression ofCCD4(4B) drives natural variation in fruit carotenoidcontent in strawberry ( Fragaria spp.)

Pigments, mainly anthocyanins and carotenoids, are important contributors to fruits visual appearance and nutritional properties. In strawberry (Fragaria spp.), the genetic and molecular mechanisms regulating fruit carotenoid biosynthesis and its natural variation remain largely unexplored. In this study, we sought to identify genomic loci contributing to variation in yellow flesh pigmentation. A major QTL, qYellow Flesh-4B, accounting for 82% of the total phenotypic variation was identified on F. x ananassa chromosome 4B. Following a candidate gene approach, we determined that CCD4(4B), a carotenoid cleavage dioxygenase (CCD), was the underlying gene. Specific polymorphisms on CCD4(4B) promoter region were associated with the yellow flesh phenotype and with differential regulation of CCD4(4B) expression during fruit ripening. Furthermore, CCD4(4B) expression levels were negatively correlated with violaxanthin, lutein, zeaxanthin, {beta}-carotene and total carotenoid content. The role of CCD4(4B) in carotenoid turnover was confirmed by transient overexpression in F. x ananassa fruits, which led to a decrease in carotenoid accumulation. Notably, a -35 C>T SNP identified in CCD4(4B) promoter was found to be predictive for CCD4(4B) expression, and carotenoid content in fruits of a diverse germplasm collection, which included different octoploid Fragaria species. Taken together, these results provide important genetic insights into the natural variation of carotenoid content in strawberry. The High-Resolution Melting (HRM) DNA test here developed offers a fast and reliable method to predict high fruit carotenoid content, representing a useful tool for breeding projects aiming to enhance the nutritional value of this crop.

plant biology↗

bioRxiv2020

CRISPR/Cas9 technology abolishes the BCR/ABL1 oncogene effect in chronic myeloid leukemia and restores normal hematopoiesis

Chronic myeloid leukemia (CML) is a hematopoietic stem cell disease produced by a unique oncogenic event involving the constitutively active tyrosine kinase (TK) BCR/ABL1. TK activity explains most features of CML, such as tumor development and maintenance. TK-inhibitory (TKI) drugs have changed its prognosis and natural history. Unfortunately, the ABL1 gene persists unaffected by TKIs, leukemic stem cells (LSCs) remains, resistant mutations arise and adverse effects may occur during treatment. To address this problem, we have designed a potential therapeutic alternative with CRISPR/Cas9 genome editing nucleases that target LSCs. The strategy was successfully developed in murine and human cell lines and finally was evaluated in primary LSCs isolated from CML transgenic mice and from CML patients. Mouse CML-LSCs edited were orthotopic transplanted in immunodeficient NSG niches where restored the normal hematopoiesis. Importantly, patient-derived xenografts with CD34+-LSCs edited, repopulated and restored the normal hematopoiesis in immunodeficient NSG niches. We show, for the first time, how CRISPR technology efficiently interrupts the BCR/ABL1 oncogene in murine and human LSCs to provide a significant therapeutic benefit. We propose human CML as a potential candidate for CRISPR therapy, providing proof-of-principle for genome editing in CML patients, and open new avenues for the application of this technique in other fusion genes. Key pointsCRISPR system destroys BCR/ABL oncogene and induces a therapeutic benefit in a CML mouse model and CML patient derived xenografts.

cancer biology↗

bioRxiv2019

ETV6/RUNX1 Fusion Gene Abrogation Decreases The Oncogenic Potencial Of Tumour Cells In A Preclinical Model Of Acute Lymphoblastic Leukaemia.

BackgroundThe t(12;21)(p13;q22), which fuses ETV6 and RUNX1 genes, is the most common genetic abnormality in children with B-cell precursor acute lymphoblastic leukaemia. The implication of the fusion protein in leukaemogenesis seems to be clear. However, its role in the maintenance of the disease continues to be controversial.\n\nAimTo eliminate the expression of the ETV6/RUNX1 fusion gene, in order to elucidate the effect in the leukaemic cells.\n\nMethodsGeneration of an in vitro ETV6/RUNX1 knock out model using the genetic modification system CRISPR/Cas9. Functional studies and generation of edited-cell xenograft model were carried out.\n\nResultsFor the first time, the expression of ETV6/RUNX1 fusion gene was completely eliminated, thus generating a powerful model on which to study the role of the fusion gene in leukaemic cells. ETV6/RUNX1 inactivation caused the deregulation of cellular processes that could be participating in the maintenance of the leukaemic phenotype, such as differentiation and lymphoid activation, apoptosis, cell signaling and cell migration. Tumour cells showed higher levels of apoptosis, lower proliferation rate and a greater sensitivity to PI3K inhibitors in vitro along as a decrease in tumour growth in xenografts models after ETV6/RUNX1 fusion gene abrogation.\n\nConclusionsETV6/RUNX1 fusion protein plays a fundamental role in the maintenance of the leukaemic phenotype, thereby being making the fusion protein a potential therapeutic target.

cancer biology↗