Project description:Application of genome-scale 'omics approaches to dissect subcellular pathways and regulatory networks governing the fast-growing response of Synechococcus sp. PCC 7002 response to variable irradience levels. We employed controlled cultivation and next-generation sequencing technology to identify transcriptional responses of euryhaline unicellular cyanobacterium Synechococcus sp. PCC 7002 grown under steady state conditions at six irradiance levels ranging from 33 to 760 µmol photons m-2 sec-1.
Project description:Cyanobacteria are photoautotrophs that profoundly impact the biogeochemical cycles on Earth. Due to their photosynthetic lifestyle that includes the fixation of atmospheric CO2, they are of increasing interest for a sustainable economy. Knowledge of protein expression and regulation is key for understanding of the cyanobacterial metabolism; however, proteome studies in cyanobacteria are still limited and cover only a fraction of the theoretical proteome. Here, we performed a proteogenomic analysis of 628 LC-MS/MS measurements for the unicellular model cyanobacterium Synechocystis sp. PCC 6803 to characterize the expressed (phospho)proteome, re-annotate known and discover potential novel open reading frames (ORFs). By mapping extensive shotgun MS proteomics data generated by the SCyCode consortium onto a six-frame translation of the Synechocystis genome, we re-annotated 96 start sites and discovered 103 novel open reading frames (ORFs). Through re-analysis of previously published multi-omics datasets, we confirmed 48 re-annotated or novel ORFs with high confidence. Our study resulted in the largest reported proteome and phosphoproteome dataset for Synechocystis, covering expression of about 80% of the theoretical proteome and 642 O-phosphorylation events under various cultivation conditions, such as nitrogen or carbon limitation. This dataset will serve as a resource providing dedicated information on condition-dependent protein expression and phosphorylation.
Project description:Cyanobacteria are photoautotrophs that profoundly impact the biogeochemical cycles on Earth. Due to their photosynthetic lifestyle that includes the fixation of atmospheric CO2, they are of increasing interest for a sustainable economy. Knowledge of protein expression and regulation is key for understanding of the cyanobacterial metabolism; however, proteome studies in cyanobacteria are still limited and cover only a fraction of the theoretical proteome. Here, we performed a proteogenomic analysis of 628 LC-MS/MS measurements for the unicellular model cyanobacterium Synechocystis sp. PCC 6803 to characterize the expressed (phospho)proteome, re-annotate known and discover potential novel open reading frames (ORFs). By mapping extensive shotgun MS proteomics data generated by the SCyCode consortium onto a six-frame translation of the Synechocystis genome, we re-annotated 96 start sites and discovered 103 novel open reading frames (ORFs). Through re-analysis of previously published multi-omics datasets, we confirmed 48 re-annotated or novel ORFs with high confidence. Our study resulted in the largest reported proteome and phosphoproteome dataset for Synechocystis, covering expression of about 80% of the theoretical proteome and 642 O-phosphorylation events under various cultivation conditions, such as nitrogen or carbon limitation. This dataset will serve as a resource providing dedicated information on condition-dependent protein expression and phosphorylation.
Project description:Iron and manganese are part of a small group of transition metals required for photosynthetic electron transport. Here, we present evidence for a functional link between iron and manganese homeostasis. In the unicellular cyanobacterium, Synechocystis sp. PCC 6803 Fe and Mn deprivation resulted in distinct modifications of the function of the photosynthetic apparatus. For example, iron limitation modifies the rate of QA re-oxidation in photosystem II, a complex that contains more Mn than Fe. The intracellular elemental quotas of Fe and Mn are also linked. Fe limitation reduces the intracellular Mn quota. Mn limitation did not exert a reciprocal effect on Fe quotas. Microarray analysis comparing Mn and Fe limitation revealed a stark difference in the extent of the transcriptional response to the two limiting conditions, reflective of the physiological data. The effects of Fe limitation on the transcriptional network are widespread while the effects on Mn limitation are highly specific. Our analysis also revealed an overlap in the transcriptional response of specific Fe and Mn transporters. This overlap provides a framework for explaining Fe limitation induced changes in Mn quotas. Fe transporters can serve as a low affinity Mn transport system. Under iron limitation the specificity of the Fe transport system changes, making it a less efficient Mn transport system.
Project description:Iron and manganese are part of a small group of transition metals required for photosynthetic electron transport. Here, we present evidence for a functional link between iron and manganese homeostasis. In the unicellular cyanobacterium, Synechocystis sp. PCC 6803 Fe and Mn deprivation resulted in distinct modifications of the function of the photosynthetic apparatus. For example, iron limitation modifies the rate of QA re-oxidation in photosystem II, a complex that contains more Mn than Fe. The intracellular elemental quotas of Fe and Mn are also linked. Fe limitation reduces the intracellular Mn quota. Mn limitation did not exert a reciprocal effect on Fe quotas. Microarray analysis comparing Mn and Fe limitation revealed a stark difference in the extent of the transcriptional response to the two limiting conditions, reflective of the physiological data. The effects of Fe limitation on the transcriptional network are widespread while the effects on Mn limitation are highly specific. Our analysis also revealed an overlap in the transcriptional response of specific Fe and Mn transporters. This overlap provides a framework for explaining Fe limitation induced changes in Mn quotas. Fe transporters can serve as a low affinity Mn transport system. Under iron limitation the specificity of the Fe transport system changes, making it a less efficient Mn transport system. We monitored the gene expression of Synechocystis PCC6083 at standard conditions and after 2 days of iron limitation (0Fe), manganese limitation (0Mn) and combined iron and manganese limitation (0Fe0Mn). Each timepoint and condition was sampled in triplicates. Due to strong deviations in one of the three repeats for the 0Mn and 0Fe0Mn conditions, the corresponding replicates were excluded from further analysis.
Project description:Investigation of whole genome gene expression level changes in two strains of the cyanobacteria Atelocyanobacterium thalasaa (UCYN-A) from environmental samples. The diel gene expression analyzed in this study is further described in Muñoz-Marin, M., I. N. Shilova, T. Shi, H. Farnelid & J. P. Zehr. 2017. Unicellular cyanobacterial symbiosis facilitates aerobic nitrogen fixation. Science (to be submitted).