The anucleate human platelets contain a broad pattern of mRNAs and other RNA transcripts. The high quantitative similarity of mRNAs in megakaryocytes and platelets from different sources points to a common origin, and suggests a random redistribution of mRNA species upon proplatelet formation. A comparison of the classified platelet transcriptome (17.6k transcripts) with the identified platelet proteome (5.2k proteins) indicates an under-representation of: (i) nuclear but not of other organellar proteins; (ii) membrane receptors and channels with low transcript levels; (iii) transcription/translation proteins; and (iv) so far uncharacterized proteins. In this review, we discuss the technical, normalization and database-dependent possibilities and challenges to come to a complete, genome-wide platelet transcriptome and proteome. Such a reference transcriptome and proteome can serve to further elucidate intra-subject and inter-subject differences in platelets in health and disease. Applications may also lay in the aid of genetic diagnostics.
Keywords: Hemostasis; megakaryocytes; platelets; proteome; quantitative proteome; quantitative transcriptome.
Blood platelets contain thousands types of mRNAs and proteins. The mRNA composition is similar to the mRNAs of megakaryocytes, from which platelets are derived, suggesting a random redistribution upon platelet formation. First attempts to identify all classified platelet proteins from mass spectral analysis used the genome-wide information of all mRNA types. This analysis revealed that the so far absent proteins in platelets are especially located in the megakaryocyte nucleus, or have low mRNA levels or low copy numbers. In this review, we discuss the possibilities to come to subject-dependent identification of the platelet protein and mRNA composition. Future applications may aid the genetic diagnostics.