Slowed decay of mRNAs enhances platelet specific translation

Area of Science:

• Hematology
• Molecular Biology
• Genomics

Background:

• Platelets are anucleate cell fragments derived from megakaryocytes (MKs).
• Platelets retain messenger RNAs (mRNAs), ribosomes, and small RNAs, enabling protein synthesis despite lacking a nucleus.
• The precise mechanisms regulating the platelet transcriptome and translation remain largely unknown.

Purpose of the Study:

• To investigate the regulatory processes shaping the platelet transcriptome.
• To determine the scope of translation occurring in human platelets.
• To elucidate the role of mRNA decay and specific factors in regulating platelet RNA content.

Main Methods:

• RNA sequencing (RNA-Seq) of primary human platelets and in vitro-derived MKs.
• Ribosome profiling of primary human platelets.
• RNA-Seq analysis of synchronized, in vitro-derived platelet-like particles.

Main Results:

• The platelet transcriptome is a subset of transcripts found in MKs, with platelet-enriched transcripts being actively translated (occupied by ribosomes).
• mRNA decay significantly shapes the nascent platelet transcriptome.
• The decay of platelet mRNAs is attenuated by the loss of the mRNA surveillance and ribosome rescue factor, Pelota.

Conclusions:

• Platelet RNA content is actively regulated post-transcriptionally, primarily through mRNA decay.
• Pelota plays a crucial role in regulating mRNA stability and decay in platelets.
• Understanding these mechanisms provides insight into platelet function and potential therapeutic targets.