Browsing by Author "Santos, Patrícia"
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- Characterization of four defense-related genes up-regulated in root nodules of Casuarina glaucaPublication . Santos, Patrícia; Fortunato, Ana; Graça, Inês; Martins, Sandra Marina; Gouveia, Maria Manuela; Auguy, Florence; Bogusz, Didier; Ricardo, Cândido Pereira Pinto; Pawlowski, Katharina; Ribeiro, AnaActinorhizal plants are capable of high rates of nitrogen fixation, due to their capacity to establish a root nodule symbiosis with N2-fixing actinomycetes of the genus Frankia. Nodulation is an ontogenic process which requires a sequence of highly coordinated events. One of these mechanisms is the induction of defense-related events, whose precise role during nodulation is largely unknown. In order to contribute to the clarification of the involvement of defense-related genes during actinorhizal root-nodule symbiosis, we have analysed the differential expression of several genes with putative defense-related functions in Casuarina glauca nodules versus non inoculated roots. Four genes encoding a chitinase (CgChi1), a glutathione S-transferase (CgGst), a hairpin-inducible protein (CgHin1) and a peroxidase (CgPox4) were found to be up-regulated in mature nodules compared to roots. In order to find out to which extend were the encoded proteins involved in nodule protection, development or both, gene regulation studies in response to SA and wounding as well as phylogenetic analysis of the protein sequences were performed. These were further characterized through expression studies after SA-treatment and wounding, and by phylogenetic analysis. We suggest that CgChi1 and CgGst are involved in defense or microsymbiont control and CgPox4 is involved in nodule development. For CgHin1 the question “defense, development or both” remains open.
- Ulcerative colitis is under dual (mitochondrial and nuclear) genetic controlPublication . Rosa, Alexandra; Abrantes, Patrícia; Sousa, Inês; Francisco, Vânia; Santos, Patrícia; Francisco, David; Xavier, Joana M.; Oliveira, Sofia A.Background: Cellular oxidative stress and genetic susceptibility have been implicated in the multifactorial etiology of ulcerative colitis (UC). The nuclear genome association with UC has been intensely investigated, but the role of the mitochondrial DNA (mtDNA) has received far less attention and may account for part of the missing heritability. This study is a comprehensive analysis of the mtDNA contribution to UC susceptibility. Methods: The association of mitochondrial single-nucleotide polymorphisms (mtSNPs) and haplogroups with UC was tested in 488 cases and 833 controls of European ancestry from the NIDDK IBD Genetics Consortium Ulcerative Colitis Genome-Wide Association Study available through dbGaP and from the Illumina Genotype Control Database (studies 64 and 65). Results: No evidence of population stratification could be detected using 218 ancestry informative markers for European Americans. Seven of the 58 tested mtSNPs were nominally associated with UC, and A10550G in MT-ND4L withstands the Bonferroni correction (P ¼ 1.29E-06, odds ratio [ORG] [95% confidence interval (CI)] ¼ 4.80 [2.54–9.05], 10550G allele: 8.1% of patients and 1.9% of controls). A10550G remains equally associated after conditional analyses on the 11 UC genome-wide association studies (GWAS) top SNPs (6.35E-07 , Pcond , 4.58E-06), which suggests that it constitutes an independent risk factor from nuclear-encoded susceptibility loci. We detected additive (but not multiplicative) epistatic interactions between A10550G and all 11 top GWAS hits. Subhaplogroup K1 (P ¼ 0.021, OR [95% CI] ¼ 1.71 [1.08–2.69]) increased the risk for UC, whereas the U5b lineage conferred protection (P ¼ 0.016, OR [95% CI] ¼ 0.34 [0.14–0.82]). Conclusions: These results suggest that UC has a dual mitochondrial and nuclear genetic control that warrants further replication in independent data sets and reinforces its etiopathogenic complexity.