Project description:In contrast to the desiccation tolerant (DT) ‘orthodox’ seeds, the so-called ‘intermediate’ seeds cannot survive complete drying and are short-lived. All species of the genus Coffea produce intermediate seeds but show a considerable variability for the seed DT level, which may help to decipher the molecular basis of seed DT in plants. We thus led a comparative transcriptome analysis of developing seeds in three coffee species with contrasting seed DT levels. Seeds of all species shared a major transcriptional switch during late maturation that governs a general slow-down of metabolism. However, numerous key stress-related genes, including those coding for the late embryogenesis abundant protein EM6 and the osmosensitive calcium channel ERD4, were upregulated during DT acquisition in the two species with high seed DT, C. arabica and C. eugenioides. By contrast, an upregulation of numerous players of the metabolism, transport and perception of auxin was observed in C. canephora seeds with low DT. Moreover, species with high DT showed a stronger down-regulation of the mitochondrial machinery dedicated to the tricarboxylic acid cycle and oxidative phosphorylation. Accordingly, respiration measurements during seed dehydration demonstrated that intermediate seeds with the highest DT levels are better prepared to cease respiration and avoid oxidative stresses.
Project description:In this study, we map sites of replication initiation and breakage in primary cells at high resolution under conditions of replication stress. We show that replication initiates between transcribed genes within nucleosome-depleted structures established by long asymmetrical poly(dA:dT) tracts flanking the initiation site. Paradoxically, large (>20 bp) homopolymeric (dA/dT) tracts are also preferential sites of polar replication fork stalling and collapse. We propose that the evolutionary expansion of poly(dA:dT) tracts in eukaryotic genomes serves to promote replication initiation, but at the cost of increasing chromosome fragility.
Project description:To dissect the molecular mechanisms underlying drought tolerance (DT) in rice, transcriptome differences of a DT introgression line H471, the DT donor P28 and the drought sensitive recurrent parent HHZ under drought stress were investigated using deep transcriptome sequencing. Results revealed a differential constitutive gene expression prior to stress and distinct global transcriptome reprogramming among three genotypes under time-series drought stress, consistent with their differential genotypes and DT phenotypes.
Project description:Myocardial CD19+CD11b+ and CD19+CD11b- cells were FACS sorted from transgenic mice expressing the Diphtheria Toxin (DT) receptor under the myocardial specific MLC2v promoter. Cells were sorted from hearts of mice not exposed to DT (naïve hearts), from the hearts of animals treated with DT 4 days prior to the experiment (DTR) and from the hearts of mice exposed to DT and fed chow enriched with the anti-inflammatory/anti-fibrotic drug Pirfenidone (0.5% in powdered chow, PFD)
Project description:To investigate the molecular mechanisms underlying the emergence and maintenance of drug-tolerant (DT) cells in anaplastic lymphoma kinase (ALK)-rearranged lung cancer, we isolated DT cells from H2228 and A925L cells exposed to high doses of alectinib or lorlatinib for 9 days, and performed transcriptome analysis between parental and DT cells using a gene expression microarray.