Poster abstracts

Poster number 40 submitted by Benjamin Warner

Role of the Leader/Trailer structure of the 17S precursor in 30S subunit biogenesis

Benjamin R. Warner (Department of Microbiology, The Ohio State University)

Abstract:
Ribosome assembly is a complex process, involving rRNA transcription, processing, and modification as well as rRNA folding and r protein binding. rRNAs are transcribed from long operons containing the three rRNA genes as a long primary transcript. The flanking sequences for the 16S and 23S are complementary and form long helices known as Leader/Trailer (L/T) helices. These helices serve as the sight of processing by several different RNases. The L/T structure of the 17S (precursor to the 16S) consists of a L/T helix as well as several leader helices. Previous data has shown this sequence is important for forming functional 30S subunits. To determine what role the L/T structure is playing in assembly, we set out to systematically disrupt the L/T structure. We were able to support one of the predicted structures based on our covariation analysis. We also showed that removing either the leader, trailer or both results in complete loss of actively translating 30S subunits. We are further targeting elements of the L/T structure to determine the critical core structure needed for 30S subunit assembly. Lastly, we are developing an in vitro FRET assay to measure 30S assembly in real time.

References:
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Mizushima, S. & Nomura, M. Assembly mapping of 30S ribosomal proteins from E. coli. Nature 226, 1214–1218 (1970).
Young, R. A. & Steitz, J. A. Complementary sequences 1700 nucleotides apart from a ribonuclease III cleavage site in Escherichia coli ribosomal precursor RNA. PNAS. U. S. A. 75, 3593–3597 (1978).

Keywords: ribosome biogenesis, RNA structure, precursor RNA