Mixed culture metagenome
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ABSTRACT:
PROVIDER: PRJNA1315275 | ENA |
REPOSITORIES: ENA
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Project description:The regulation of gene expression and RNA maturation underlies fundamental processes such as cell homeostasis, development and stress acclimation. The biogenesis and modification of RNA is tightly controlled by an array of regulatory RNAs and nucleic acid-binding proteins. While the role of small RNAs (sRNAs) in gene expression has been studied in-depth in select model organisms, little is known about sRNA biology across the eukaryotic tree of life. We used deep sequencing to explore the repertoires of sRNAs encoded by the miniaturized, endosymbiotically-derived ‘nucleomorph’ genomes of two single-celled algae, the cryptophyte Guillardia theta and the chlorarachniophyte Bigelowiella natans. A total of 32.3 and 35.3 million reads were generated from G. theta and B. natans, respectively. In G. theta, we identified nucleomorph U1, U2 and U4 spliceosomal RNAs (snRNAs) as well as 11 C/D box small nucleolar RNAs (snoRNAs), five of which have potential plant and animal homologs. The snoRNAs are predicted to perform 2’-O methylation of rRNA (but not snRNA). In B. natans, we found previously undetected RNA components of the nucleomorph spliceosome (U4 snRNA) and ribosome (5S rRNA), along with six orphan sRNAs. Analysis of chlorarachniophyte snRNAs shed light on the removal of the miniature 18-21 nt introns found in B. natans nucleomorph genes. Neither of the nucleomorph genomes appears to encode RNA pseudouridylation machinery, and U5 snRNA cannot be found in the cryptophyte. Considering the central roles of U5 snRNA and RNA modifications in other organisms, cytoplasm-to-nucleomorph RNA shuttling in cryptophyte algae is a distinct possibility.
2019-01-09 | GSE124831 | GEO
Project description:Plants and algae have developed various light harvesting mechanisms for optimal delivery of excitation energy to the photosystems. The cryptophyte algae have evolved a novel soluble light-harvesting antenna utilizing phycobilin pigments to complement the membrane-intrinsic Chl a/c-binding LHC antenna. This new antenna consists of the plastid-encoded beta-subunit, a relict of the ancestral phycobilisome, and a novel nuclear-encoded -subunit unique to cryptophytes. Together, these proteins form the active tetramer, which consists of one alpha 1 and one alpha 2 and two beta susbunits. In all cryptophyte algae investigated so far, the alpha-subunits have duplicated and diversified into a large gene family. Although there is transcriptional evidence for expression of all these genes, the x-ray structures determined to date suggest that only two of the -subunit genes might be significantly expressed at protein level. Using proteomics, we show that phycoerythrin 545 (PE545) of Guillardia theta, the only cryptophyte with a sequenced genome, all 20 alpha-subunits are expressed when the algae grow under white light. Their relative expression levels depend on the intensity of the growth light, but there is no evidence for a specific light-dependent regulation of individual members of the alpha-subunit family under the growth conditions applied. Subunit GtcpeA10 seems to be a special member of the alpha-subunit family, because it consists of two similar N- and C-terminal domains, which likely are the result of a partial gene duplication.
2017-06-20 | PXD006301 | Pride
Project description:Nucleomorph small RNAs in cryptophyte and chlorarachniophyte algae
| PRJNA513882 | ENA
Project description:The Atlantic killifish (Fundulus heteroclitus) is an ideal model species to study physiological and toxicological adaptations to stressors. Killifish inhabiting the PCB-contaminated Superfund site in New Bedford Harbor, MA (NBH) have evolved resistance to toxicity and activation of the aryl hydrocarbon receptor (AHR) signaling pathway after exposure to PCBs and other AHR agonists. Until recently, a lack of genomic information has limited efforts to understand the molecular mechanisms underlying environmental adaptation to stressors. The advent of high throughput sequencing has facilitated an unbiased assessment of coding as well as non-coding RNAs in any species of interest. Among non-coding RNAs, microRNAs (miRNAs) are important regulators of gene expression and play crucial roles in development and physiology. The objective of this study is to catalog the miRNAs in killifish and determine their expression patterns in the embryos from contaminated (NBH) and pristine (Scorton Creek, MA (SC)) sites. Embryos from NBH and SC were collected daily from 1 to 15 days post-fertilization and RNA from pooled samples from each site was sequenced using SOLiD sequencing. We obtained 7.5 and 11 million raw reads from pooled SC and NBH samples, respectively. Analysis of the sequencing data identified 216 conserved mature miRNA sequences that are expressed during development. Using the draft killifish genome, we retrieved the miRNA precursor sequences. Based on the capacity of these putative precursor sequences to form the characteristic hairpin loop (assessed using RNAfold), we identified 197 conserved miRNA sequences in the genome.
2015-07-20 | GSE70953 | GEO
Project description:Contaminated algal culture microbial communities from Pecos, Texas, USA - Monoraphidium minutum 26B-AM
| PRJNA712877 | ENA