Neva Caliskan

Neva Caliskan

Max Planck Institute for Biophysical Chemistry, Gottingen, Germany



Biography

Dr. Neva Caliskan pursued her Master`s and doctoral studies at the Max Planck Research School for Molecular Biology in Göttingen. Thereafter she stayed in Göttingen as a post doctoral researcher and later as a project leader at the Max Planck Institute for Biophysical Chemistry in the department of Physical Biochemistry. Her research focuses on characterization of unusual translation events, particularly ribosome frameshifting by using rapid kinetic analysis tools. From 2018 onwards she is appointed as a group leader at the Helmholtz Institute for RNA-based Infection Biology in Würzburg.

Abstract

Ribosome frameshifting during translation of bacterial dnaX can proceed via different routes, generating a variety of distinct polypeptides. Using kinetic experiments, we show that –1 frameshifting predominantly occurs during translocation of two tRNAs bound to the slippery sequence codons. This pathway depends on a stem-loop mRNA structure downstream of the slippery sequence and operates when aminoacyl-tRNAs are abundant. However, when aminoacyl-tRNAs are in short supply, the ribosome switches to an alternative frameshifting pathway that is independent of a stem-loop. Ribosome stalling at a vacant 0-frame A-site codon results in slippage of the P-site peptidyl-tRNA, allowing for –1-frame decoding. When the –1-frame aminoacyl-tRNA is lacking, the ribosomes switch into –2 frame. Quantitative mass spectrometry shows that the –2-frame product is synthesized in vivo. We suggest that switching between frameshifting routes may enrich gene expression at conditions of aminoacyl-tRNA limitation.