Title | Nitrogen cost minimization is promoted by structural changes in the transcriptome of N-deprived Prochlorococcus cells. |
Publication Type | Journal Article |
Year of Publication | 2017 |
Authors | Read, RW, Berube, PM, Biller, SJ, Neveux, I, Cubillos-Ruiz, A, Chisholm, SW, Grzymski, JJ |
Journal | ISME J |
Volume | 11 |
Issue | 10 |
Pagination | 2267-2278 |
Date Published | 2017 Oct |
ISSN | 1751-7370 |
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. |
DOI | 10.1038/ismej.2017.88 |
Alternate Journal | ISME J |
PubMed ID | 28585937 |
PubMed Central ID | PMC5607370 |