Poster abstracts
Poster number 74 submitted by Daniel L Kiss
The relationship of mRNA 5’ ends generated by cap homeostasis to translation
Daniel L. Kiss (Center for RNA Biology, Department of Biological Chemistry and Pharmacology,The Ohio State University, Columbus, Ohio 43210), William D Baez (Center for RNA Biology, Department of Physics, and Division of Hematology,The Ohio State University, Columbus, Ohio 43210), Bernice Agana (Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210), Vicki H Wysocki (Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210), Ralf Bundschuh (Center for RNA Biology, Department of Physics, and Division of Hematology,The Ohio State University, Columbus, Ohio 43210), Daniel R Schoenberg (Center for RNA Biology, Department of Biological Chemistry and Pharmacology,The Ohio State University, Columbus, Ohio 43210)
Abstract:
Until recently, removal of the 5’ cap structure was thought to be an irreversible step leading to the degradation of the decapped mRNA. Our lab has discovered and characterized a cytoplasmic capping enzyme (CE) complex that includes capping enzyme and a 5’ monophosphate RNA kinase assembled on the two most C-terminal SH3 domains of the scaffold protein Nck1. This complex promotes the stability and translation of specific mRNAs by restoring the 5’ cap onto their decapped forms. Previous work used a line of cells expressing an inducible dominant negative form of CE (K294A) to identify cytoplasmic capping targets. Uncapped forms of these mRNAs accumulate in non-translating mRNPs and retain translationally competent poly(A) tails. Data from capped analysis of gene expression (CAGE) was used to refine experiments using 5’ RACE to identify the 5’ ends of these transcripts. In agreement with the published CAGE data, these results show a subset of mRNAs can be recapped at multiple locations to generate 5’ truncated mRNAs. This was examined further by ribosome profiling to ascertain the prevalence and functional effects of cap homeostasis across the translating transcriptome. Results will be presented that show decapping and recapping (cap homeostasis) is a mechanism by which cells regulate the translation of a subset of mRNAs.
Keywords: cytoplasmic capping, cap homeostasis, sequencing