Project description:Haploid (1N) and diploid (2N) Emiliania huxley (RCC 1217 and RCC1216) were grown in dilute batch culture and achieved stationary phase. We sampled two time points, at early (T2) and late (T3) stationary phase. Controls are haploid or diploid cells derived from dilute cultures (T1) growing in replete control medium. All samples were hybridized against a common, pooled baseline RNA. All experiments and hybridization were done in independent biological triplicates (A, B and C).
Project description:Haploid (1N) and diploid (2N) cells of Emiliania huxley (RCC 1217/1216) were grown under 50 and 300 µmol photons m-2 s-1. Differential gene expression was assessed between the ploidy stages at same irradiance and between the light treatments of same strains.
Project description:Investigation of the genetic diversity of Emiliania huxleyi, genomic DNA from 15 different strains were compared with the genomic DNA of the sequenced E. huxleyi strain CCMP1516. Gephyrocapsa oceanica and Isochrysis galbana as phylogenetic closely related taxa were used as out-groups.
Project description:Gene expression analysis of Emiliania huxleyi after 6, 12 and 24 hours of viral infection infected with the virus EhV-86 in comparison to an unifected culture.
Project description:The abundant and widespread coccolithophore Emiliania huxleyi plays an important role in mediating CO2 exchange between the ocean and the atmosphere through its impact on marine photosynthesis and calcification. Here, we use long serial analysis of gene expression (SAGE) to identify E. huxleyi genes responsive to nitrogen (N) or phosphorus (P) starvation. Long SAGE is an elegant approach for examining quantitative and comprehensive gene expression patterns without a priori knowledge of gene sequences via the detection of 21-bp nucleotide sequence tags. E. huxleyi appears to have a robust transcriptional-level response to macronutrient deficiency, with 42 tags uniquely present or up-regulated twofold or greater in the N-starved library and 128 tags uniquely present or up-regulated twofold or greater in the P-starved library. The expression patterns of several tags were validated with reverse transcriptase PCR. Roughly 48% of these differentially expressed tags could be mapped to publicly available genomic or expressed sequence tag (EST) sequence data. For example, in the P-starved library a number of the tags mapped to genes with a role in P scavenging, including a putative phosphate-repressible permease and a putative polyphosphate synthetase. In short, the long SAGE analyses have (i) identified many new differentially regulated gene sequences, (ii) assigned regulation data to EST sequences with no database homology and unknown function, and (iii) highlighted previously uncharacterized aspects of E. huxleyi N and P physiology. To this end, our long SAGE libraries provide a new public resource for gene discovery and transcriptional analysis in this biogeochemically important marine organism. Keywords: Emiliania, gene expression, nutrients, SAGE, phosphate, nitrogen Emiliania huxleyi CCMP 1516 was obtained from the Provasoli-Guillard Center for the Culture of Marine Phytoplankton, Bigelow Laboratories. Cultures were grown at 18°C on a 14 h:10 h light:dark cycle (140 µmol quanta m-2 s-1). Nitrogen and phosphate replete (Replete: 35 µM NO3- and 1.5 µM PO43-), low nitrogen (-N: 10 µM NO3-) and low phosphate (-P: 0 µM PO43-) cells were grown in f/50 medium without Si. Locally collected seawater was filtered (pore size, 0.2 µm) and autoclaved. Filter-sterilized inorganic nutrients, trace metals and vitamins (thiamin, biotin and B12) were added after autoclaving. The cells were grown in 8 L batch cultures. The growth of cultures was monitored daily by cell number counted on a hemacytometer, and by relative fluorescence using a Turner Designs AU Fluorometer. Replete cells were harvested in mid-log phase while –N and –P cells were harvested at the onset of stationary phase for SAGE analysis.
Project description:Pre-mRNA splicing relies on the still poorly understood dynamic interplay between more than 150 protein components of the Spliceosome, and the steps at which splicing can be regulated remain largely unknown. Here we systematically analyze the effect of knocking down the components of the splicing machinery on alternative splicing events relevant for cell proliferation and apoptosis and use this information to reconstruct a network of functional interactions. The network accurately captures well-established physical and functional associations and identifies new, revealing remarkable regulatory potential of core spliceosomal components, related to the order and duration of their recruitment during Spliceosome assembly. In contrast with standard models of regulation at early events of splice site recognition, factors involved in catalytic activation of the Spliceosome display regulatory properties. The network also sheds light on the antagonism between hnRNP C and U2AF and on targets of anti-tumor drugs, and can be widely used to identify mechanisms of splicing regulation. RNA from 3 biological replicates of 72 hours knockdowns of human IK or SMU1 and a control set were used. Changes between the control and knockdowns were measured based on using a splice-junction array (Affymetrix HJAY).