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Working on the issue of mRNA processing has been done in exponentially growing cells, while only little is known about this essential process in transition and stationary growing cells. Thus, this research in the stationary phase is especially important due to the fact that under natural conditions bacteria are predominantly found in stationary growth. The gram-positive organism Bacillus subtilis serves as a model organism in many aspects and is already well-studied in many topics including competence, sporulation, and motility. The focus especially on B. subtilis is based on its ability to decide between different cell fates at the transition from exponential to stationary growth. Adjustment of protein levels and therefore availability and stability of mRNA is needed to ensure survival during adverse conditions. So far, a number of specific sigma factors like Sig H, Sig C, Sig D, and Sig B (σ38, Escherichia coli) as well as RNA-binding proteins, are known for the modification and thus regulation of mRNA levels in stationary growing B. subtilis cells. However, the involvement and regulation of ribonucleases (RNases) are largely unknown in this context, which definitively have a crucial role in regulating the protein levels and therefore, the energy of the cell. In B. subtilis 20 RNases are known of which some may be involved in this process.
Understanding these regulatory processes in stationary growing gram-positive and gram-negative bacteria will help to improve a better understanding of regulatory processes at the mRNA level in the bacterial cell.
Sources used:
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