Project description:In order to analyze the responses of a heterocystous cyanobacterium to combined-nitrogen depletion/addition, we have used customized microarrays to identify genes potentially involved in heterocysts differentiation by comparing the responses in the control strain and a hetR mutant unable to differentiate heterocysts. RNA samples were isolated from cells growing in the presence of combined nitrogen (ammonium) or after 6, 8, 12 or 24 h of nitrogen deprivation. Additionally, RNA was isolated from cells growing in the absence of combined nitrogen or 8 h after addition of ammonium
Project description:Change in gene expression for a wild-type (Nostoc punctiforme ATCC 29133) and hmpD-deletion strain (UCD 543) of Nostoc punctiforme ATCC 29133 over the time course of hormogonium development This study is further descirbed in Risser, D.D. and Meeks, J.C. 2013. Comparative transcriptomics with a motility deficient mutant leads to identification of a novel polysaccharide secretion system in Nostoc punctiforme. Molecular Microbiology
Project description:Change in gene expression for a wild-type (Nostoc punctiforme ATCC 29133) and hmpD-deletion strain (UCD 543) of Nostoc punctiforme ATCC 29133 over the time course of hormogonium development This study is further descirbed in Risser, D.D. and Meeks, J.C. 2013. Comparative transcriptomics with a motility deficient mutant leads to identification of a novel polysaccharide secretion system in Nostoc punctiforme. Molecular Microbiology Total RNA from 3 biological replicates at each time point from 0 to 24 hours after hormogonium induction was converted to cDNA, dye-labled and hybridized to nimblegen 12x135k array slides
Project description:To identify the mechanisms of the adaptation to terrestrial ecosystems, an RNA-seq based transcriptome analysis was conducted on a desiccation resistant cyanobacterium, Nostoc sp. MG11.
Project description:Here, we report the comparison of transcriptomes of Anabaena sp. PCC7120 and a FurC-overexpressing derivative strain grown under standard conditions (BG11) and after 48 hours of nitrogen step-down (BG110). Anabaena sp PCC7120 is a cyanobacterium that differentiates specialized nitrogen-fixing cells called heterocysts. Our data suggests that FurC directly controls the regulation of heterocyst differentiation and nitrogen fixation in this cyanobacterium. In addition, we found that FurC is also clearly involved in the regulation of several genes belonging to different functional categories, such as iron metabolism, photosynthesis and regulatory functions.
Project description:Transcriptomic analyses using high-throughput methods have revealed abundant antisense transcription in bacteria. Most frequently, antisense transcription is due to the overlap of mRNAs with long 5’ regions or 3’ ends that extend beyond the coding sequence. In addition, antisense RNAs that do not contain any coding sequence are also observed. Nostoc sp. PCC 7120 is a filamentous cyanobacterium that, under nitrogen limitation, behaves as a multicellular organism with division of labor among two different cell types that depend on each other, the vegetative CO2-fixing cells and the nitrogen-fixing heterocysts. Differentiation of heterocysts depends on the global nitrogen regulator NtcA and requires the specific regulator HetR. To identify antisense RNAs potentially involved in heterocyst differentiation we performed an RNA-Seq analysis of cells subjected to nitrogen limitation (either at 9 or 24 hours after nitrogen removal) and analyzed the results in combination with a genome-wide set of nitrogen-regulated transcriptional start sites and a prediction of transcriptional terminators. Our analysis resulted in the definition of a transcriptional map including more than 4,000 transcripts, 65% of them in antisense orientation to other transcripts. In addition to overlapping mRNAs we identified nitrogen-regulated non-coding antisense RNAs transcribed from NtcA-dependent or HetR-dependent promoters.
Project description:Here, we report the comparison of transcriptomes of Anabaena sp. PCC7120 and the FurB(Zur) deletion derivative strain (MN38). Anabaena sp PCC7120 is a cyanobacterium that differentiates specialized nitrogen-fixing cells called heterocysts and that is capable of forming biofilms. Our data showed that the deletion of FurB negativily affected the heterocyst development and the biofilm formation. In addition, the RNA-seq data together with gel retardation assays unveiled that FurB is directly involved in the regulation of several genes related to heterocyst development and biofilm formation and other novel functions different from the ones related to the canonical Zur regulon.