Nitrogen cost minimization is promoted by structural changes in the transcriptome of N-deprived Prochlorococcus cells
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Author(s)
Read, Robert W
Neveux, Iva
Grzymski, Joseph J
Berube, Paul M.
Biller, Steven
Cubillos, Andres Fernando
Chisholm, Sallie (Penny)
Date Issued
June 2017
Journal
ISME Journal
Publisher
Nature Publishing Group
Citation
Read, Robert W et al. “Nitrogen Cost Minimization Is Promoted by Structural Changes in the Transcriptome of N-Deprived Prochlorococcus Cells.” The ISME Journal 11, 10 (June 2017): 2267–2278 © 2017 International Society for Microbial Ecology
Version
Final published version
Abstract
Prochlorococcus is a globally abundant marine cyanobacterium with many adaptations that reduce cellular nutrient requirements, facilitating growth in its nutrient-poor environment. One such genomic adaptation is the preferential utilization of amino acids containing fewer N-atoms, which minimizes cellular nitrogen requirements. We predicted that transcriptional regulation might further reduce cellular N budgets during transient N limitation. To explore this, we compared transcription start sites (TSSs) in Prochlorococcus MED4 under N-deprived and N-replete conditions. Of 64 genes with primary and internal TSSs in both conditions, N-deprived cells initiated transcription downstream of primary TSSs more frequently than N-replete cells. Additionally, 117 genes with only an internal TSS demonstrated increased internal transcription under N-deprivation. These shortened transcripts encode predicted proteins with an average of 21% less N content compared to full-length transcripts. We hypothesized that low translation rates, which afford greater control over protein abundances, would be beneficial to relatively slow-growing organisms like Prochlorococcus. Consistent with this idea, we found that Prochlorococcus exhibits greater usage of glycine-glycine motifs, which causes translational pausing, when compared to faster growing microbes. Our findings indicate that structural changes occur within the Prochlorococcus MED4 transcriptome during N-deprivation, potentially altering the size and structure of proteins expressed under nutrient limitation.
MIT Department
Massachusetts Institute of Technology. Department of Biology
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Massachusetts Institute of Technology. Microbiology Graduate Program
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Creative Commons Attribution 4.0 International License
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DOI of Published Version
https://doi.org/10.1038/ISMEJ.2017.88
