microRNA in erythrocytes

Mammalian erythrocytes are generally thought to lack RNA and therefore to be unable to translate new proteins in response to internal or external signals. Support for this long-standing view has accumulated from diverse studies, most of which have focused on the total content of RNA or the overall level of translation. However, more recent work on specific types of RNA has shown the presence in human erythrocytes of both Y RNA and microRNA. The latter seem particularly incongruous given that their normal role is to attenuate the translation of mRNA. Y RNA binds the Ro autoantigen which may have a role in cellular RNA quality control. Therefore the presence of both of these non-coding RNAs indicates the possible existence of other cryptic RNAs in erythrocytes. It also suggests either the existence of low levels of translation or new uncharacterized processes involving microRNA in these cells.