Poster abstracts
Poster number 121 submitted by Bappaditya Roy
Global analysis of protein synthesis in Flavobacterium johnsoniae reveals the use of Kozak-like sequences in diverse bacteria
Bappaditya Roy (Department of Microbiology, Center for RNA Biology, The Ohio State University, Columbus, OH 43210), William D. Baez (Department of Physics, Center for RNA Biology, The Ohio State University, Columbus, OH 43210), Zakkary A. McNutt (Department of Microbiology, Ohio State Biochemistry Program, Center for RNA Biology, The Ohio State University, Columbus, OH 43210), Elan A. Shatoff (Department of Physics, Center for RNA Biology, The Ohio State University, Columbus, OH 43210), Ralf Bundschuh (Department of Physics, Department of Chemistry and Biochemistry, Division of Hematology, Department of Internal Medicine, Center for RNA Biology, The Ohio State University, Columbus, OH 43210), Kurt Fredrick (Department of Microbiology, Ohio State Biochemistry Program, Center for RNA Biology, The Ohio State University, Columbus, OH 43210)
Abstract:
In all cells, initiation of translation is tuned by intrinsic features of the mRNA. Here, we analyze translation in F. johnsoniae, a representative of the Bacteroidetes. Members of this phylum naturally lack Shine-Dalgarno (SD) sequences in their mRNA, and yet their ribosomes retain the conserved anti-SD sequence. Translation initiation is tuned by mRNA secondary structure and by the identities of several key nucleotides upstream of the start codon. Positive determinants include adenine at position -3, reminiscent of the Kozak sequence of Eukarya. Comparative analysis of E. coli reveals use of the same Kozak-like sequence to enhance initiation, suggesting an ancient and widespread mechanism. Elimination of contacts between A-3 and the conserved beta-hairpin of ribosomal protein uS7 fails to diminish the contribution of A-3 to initiation, suggesting an indirect mode of recognition. Also, we find that, in the Bacteroidetes, the trinucleotide AUG is underrepresented in the vicinity of the start codon, which presumably helps compensate for the absence of SD sequences in these organisms.
Keywords: Kozak sequences, Initiation