Project description:The coordination of chloroplast and nuclear genome status are critical for plant cell function, but the mechanism remain largely unclear. In this study, we report that Arabidopsis thaliana CHLOROPLAST AND NUCLEUS DUAL-LOCALIZED PROTEIN 1 (CND1) maintains genome stability in both the chloroplast and the nucleus.
Project description:Chloroplast, the energy organelle unique to plants and green algae, performs a wide range of functions including photosynthesis and biosynthesis of metabolites. However, as the most important tuber crop worldwide, the potato (Solanum tuberosum) chloroplast proteome has not been explored. Here, we use Percoll density gradient centrifugation to isolate intact chloroplasts from leaves of potato cultivar E3 and establish a reference proteome map of potato chloroplast by bottom-up proteomics. A total of 1834 non-redundant proteins, including 51 proteins encoded by the chloroplast genome, were identified in the chloroplast proteome. Extensive sequence-based localization prediction revealed over 62% of proteins to be chloroplast resident by at least one algorithm. A total of 16 proteins were selected for evaluating the prediction result by transient fluorescence assay and confirmed that 14 of them were distributed on distinct internal compartments of the chloroplast. In addition, 136 phosphorylation sites were identified in 61 proteins encoded by chloroplast proteome. Furthermore, by a comparative analysis between chloroplast and previously reported amyloplast proteomes, we reconstruct the starch metabolic pathways in the two different types of plastids. Altogether, our results establish a comprehensive proteome map with post-translationally modified sites of potato chloroplast, which would provide the theoretical principle for the research of photosynthesis pathway and starch metabolism.
Project description:Map the origins of DNA replication in human cells at 7 common fragile sites and their flanking non-fragile sequences as well as a 200kb containing the rare fragile site FRAXA, and a 1,075kb non-fragile region on chr22 . The origins were mapped in untreated cells, as well as, in cells treated with aphidicolin (APH), trichostatin A (TSA), or APH plus TSA. The origin mapping experiment is based on the fact that during S phase, short newly replicated DNA fragments (300bp-1kb) are generated only at the origins of replication. By combining the nascent strand assay with a tiled microarray platform, we have previoulsy developed a rapid, non-PCR based, high-throughput approach to map active origins in asynchronous human cells (Lucas et al., 2007, AC 17668008).
Project description:The coordination of chloroplast and nuclear genome status are critical for plant cell function, but the mechanism remain largely unclear. In this study, we report that Arabidopsis thaliana CHLOROPLAST AND NUCLEUS DUAL-LOCALIZED PROTEIN 1 (CND1) maintains genome stability in both the chloroplast and the nucleus.
Project description:The goal of this study is to identify transcriptome changes by the RPGE overexpression or glk1/glk2 double mutant under white light. We compared the transcriptome of RPGE2-OX (35Spro::GFP-RPGE2) with wild type (Col-0) and glk12 (glk1/glk2 double mutant) with wild type in continuous white light to investigate the expression changes of genes which are related with chloroplast development and the relationship between RPGE and GLK in the chloroplast development process.
Project description:GUN1 integrates retrograde signals in the chloroplast but the underlying mechanism is elusive. FUG1, a chloroplast translation initiation factor, and GUN1 are co-expressed at the transcript level, and FUG1 co-immunoprecipitates with GUN1. We used mutants of GUN1 (gun1-103) and FUG1 (fug1-3) to analyse their functional relationship at the physiological and systems-wide level, the latter including transcriptome and proteome analyses. Absence of GUN1 aggravates the effects of decreased FUG1 levels on chloroplast protein translation, resulting in transient additive phenotypes with respect to photosynthesis, leaf coloration, growth and cold acclimation. Variegation of the var2 mutant is enhanced by gun1-103 in terms of increasing the fraction of white sectors, in contrast to fug1-3 that acts as suppressor. The transcriptomes of fug1-3 and gun1-103 are very similar, but absence of GUN1 alone has almost no effects on protein levels, whereas chloroplast protein accumulation is markedly decreased in fug1-3. In gun1 fug1 double mutants, effects on transcriptomes and particularly proteomes are enhanced. Our results show that GUN1 function becomes critical when chloroplast proteostasis is perturbed by decreased translation (fug1) or degradation (var2) of chloroplast proteins. The functions of FUG1 and GUN1 appear to be related, corroborating the view that GUN1 operates in chloroplast proteostasis.