RNA as a genetic information carrier
Though often ignored, most organisms inherit more RNA than DNA from their parents. It is unclear whether this RNA has any role in the transfer of genetic information. The same holds for cell-free or extracellular RNA. Just their (abundant) present in eggs and for instance breast milk, respectively, hints on an intriguing role in of RNA in development and evolution by transfer of genetic information between cells, organs, and individuals.
Oocytes accumulate a large pool of RNA molecules that play a role in the orchestration of the subsequent embryonic development, for instance in the maternal to zygote transition and cell fate decisions. Probably all types of RNA and mRNA from the majority of the genes are present. A complicated system involving changing polyadenylation of RNA molecules regulates the activation and degradation of maternal RNAs. Neither the exact composition, appearance, nor all the roles for the maternal RNAs are known. There is also still debate whether all maternal RNAs originate from the oocyte and/or are deposited via other cells.
Cell free RNA
Cell free RNA can be found in all bodily fluids. It is either packed in so called microvesicles or proteins to protect them from the RNases that are abundantly present in these fluids. Both miRNAs as mRNAs are found as cell free RNA. These RNAs originate from different pools of genes in each tested bodily fluid, which might hint on an active role for these RNAs. It is hypothesized that they constitute a new form of cell-to-cell communication. Recently also cell free RNAs from species that are food are found in serum, which effectively means transfer of intact genetic material from one species to another. Although cell free RNA (and DNA) are an emerging source of biomarkers for a wide variety of diseases, their biological functions are yet unknown. With the current next-generation sequencing technology it is possible to characterize and investigate cell free RNAs.
People working on this research line:
Dr. Rob Dekker
R.J.Dekker at uva.nl