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Analyzing Gene Expression from Marine Microbial Communities using Environmental Transcriptomics
Published on: February 18, 2009
Metatranscriptomics reveals unique microbial small RNAs in the ocean's water column
Yanmei Shi1, Gene W Tyson, Edward F DeLong
1Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Nature
|May 16, 2009
Summary
Metatranscriptomic studies reveal that many microbial RNA sequences are small RNAs (sRNAs), including novel ones. These sRNAs play roles in microbial adaptation and environmentally relevant processes like nutrient acquisition.
Area of Science:
- Microbiology
- Genomics
- Bioinformatics
Background:
- Metatranscriptomic studies analyze microbial gene expression directly from environmental samples.
- Previous analyses identified many unknown RNA sequences, suggesting uncharacterized proteins.
Purpose of the Study:
- To investigate the nature of previously uncharacterized complementary DNA sequences found in microbial metatranscriptomic data.
- To identify and characterize novel small RNAs (sRNAs) and their potential functions in natural microbial communities.
Main Methods:
- Analysis of complementary DNA sequences from pyrosequencing of total RNA from natural microbial assemblages.
- Mapping of putative sRNAs (psRNAs) to intergenic regions of microbial genomes.
- Assessment of secondary structures and flanking genes for regulatory function indicators.
- Examination of depth-dependent variation and genome-specific mapping of psRNAs.
Main Results:
- A significant fraction of cDNA sequences in metatranscriptomic datasets are known and novel small RNAs (sRNAs).
- Novel psRNAs map to intergenic regions, possess conserved secondary structures, and are near potential regulatory genes.
- psRNA variations correlate with taxonomic distribution and suggest roles in niche adaptation.
- Analysis of Pelagibacter revealed known and new regulatory elements within psRNAs.
Conclusions:
- Metatranscriptomics is a powerful tool for discovering the diversity, distribution, and abundance of sRNAs in microbial communities.
- Identified sRNAs are involved in critical environmental processes, including carbon metabolism and nutrient acquisition.
- This study expands our understanding of microbial regulatory networks and adaptation strategies.
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