Cell-Type-Specific Profiling of Alternative Translation Identifies Regulated Protein Isoform Variation in the Mouse Brain

Darshan Sapkota, Allison M. Lake, Wei Yang, Chengran Yang, Hendrik Wesseling, Amanda Guise, Ceren Uncu, Jasbir S. Dalal, Andrew W. Kraft, Jin-Moo Lee, Mark S. Sands, Judith A. Steen, Joseph D. Dougherty. Cell Reports, Volume 26, Issue 3, 15 January 2019, Pages 594-607.e7
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Abstract

Alternative translation initiation and stop codon readthrough in a few well-studied cases have been shown to allow the same transcript to generate multiple protein variants. Because the brain shows a particularly abundant use of alternative splicing, we sought to study alternative translation in CNS cells. We show that alternative translation is widespread and regulated across brain transcripts. In neural cultures, we identify alternative initiation on hundreds of transcripts, confirm several N-terminal protein variants, and show the modulation of the phenomenon by KCl stimulation. We also detect readthrough in cultures and show differential levels of normal and readthrough versions of AQP4 in gliotic diseases. Finally, we couple translating ribosome affinity purification to ribosome footprinting (TRAP-RF) for cell-type-specific analysis of neuronal and astrocytic translational readthrough in the mouse brain. We demonstrate that this unappreciated mechanism generates numerous and diverse protein isoforms in a cell-type-specific manner in the brain.

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Posted on January 22, 2019
Posted in: HPAN, Lysosome, Neurodegeneration, Neurogenetics & Transcriptomics, Neurovascular Injury & Repair, Pilot Projects, Publications Authors: , ,