Book of Abstracts: Albany 2009
June 16-20 2009
© Adenine Press (2008)
Regulatory RNAs in Bacteria: Biological Roles and Mechanisms
Small non-coding RNAs play central regulatory roles in all kingdoms of life. My lab is concerned with such RNAs (here called small RNAs/ sRNAs) in the enterobacterium Escherichia coli. Most bacterial sRNAs whose biological roles have been elucidated appear to be stress-related (membrane stress , oxidative stress, SOS/ DNA damage, sugar stress, cold shock, iron stress etc.), and some are involved in pathogenesis. The emerging picture suggests that many adaptive responses involve a complex interplay of transcriptional and post-transcriptional regulation, the latter being predominantly carried out by sRNAs. This is strongly supported by sRNA dependent remodeling of the cell surface and outer membrane.
In terms of mechanisms, a few sRNAs carry out their regulatory activity by protein sequestration whereas the majority acts by base-pairing (antisense mechanism) to target mRNAs. For these antisense sRNAs, inhibition of translational initiation appears to be the predominant mode. Many sRNAs bind to translation initation regions and thereby compete with ribosome access. A second mode of action is translational activation. Here, sRNAs bind to an upstream RNA segment to unmask an otherwise inhibitory structure sequestering the ribosome binding site. Other more exotic mechanisms have been elucidated, such as antisense RNA competing for sequence non-specific "ribosome standby" binding [2,3] (so-called ribosome standby).
This talk will summarize some of the biological roles that sRNAs play in enterobacteria and will give examples of mechanisms of regulation.
References and Footnotes
E. Gerhart H. Wagner
Dept. of Cell & Molecular Biology