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Slowed decay of mRNAs enhances platelet specific translation

Eric W. Mills, Rachel Green and Nicholas T. Ingolia

Key points

  • Ribosome profiling of primary human platelets defines the platelet translatome, derived from a biased subset of megakaryocyte mRNAs.

  • Restoration of the ribosome rescue/mRNA surveillance factor Pelota, which is normally absent in wild type platelets, promotes RNA decay.

Abstract

Platelets are anucleate cytoplasmic fragments that lack genomic DNA, but continue to synthesize protein using a pool of mRNAs, ribosomes, and regulatory small RNAs inherited from the precursor megakaryocyte (MK). The regulatory processes that shape the platelet transcriptome and the full scope of platelet translation have remained elusive. Using RNA-Seq and ribosome profiling of primary human platelets, we show the platelet transcriptome encompasses a subset of transcripts detected by RNA-Seq analysis of in vitro derived MK cells and these platelet-enriched transcripts are broadly occupied by ribosomes. We use RNA sequencing of synchronized populations of in vitro derived platelet-like particles (PLPs) to show that mRNA decay strongly shapes the nascent platelet transcriptome. Our data suggests that the decay of platelet mRNAs is slowed by the natural loss of the mRNA surveillance and ribosome rescue factor Pelota (PELO).

  • Submitted August 25, 2016.
  • Accepted December 31, 2016.