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Nitrogen cost minimization is promoted by structural changes in the transcriptome of N-deprived Prochlorococcus cells.

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.

SUBMITTER: Read RW

PROVIDER: S-EPMC5607370 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature

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Nitrogen cost minimization is promoted by structural changes in the transcriptome of N-deprived Prochlorococcus cells.

Read Robert W RW Berube Paul M PM Biller Steven J SJ Neveux Iva I Cubillos-Ruiz Andres A Chisholm Sallie W SW Grzymski Joseph J JJ

The ISME journal 20170606 10

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 ...[more]

PMID: 28585937

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Nitrogen cost minimization is promoted by structural changes in the transcriptome of N-deprived Prochlorococcus cells.

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Nitrogen cost minimization is promoted by structural changes in the transcriptome of N-deprived Prochlorococcus cells.

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