The main function of RNA was identified early on as being a template – in the form of messenger RNA that reflects the encoding of genes in DNA – for the construction of proteins. A few other forms of RNA were also recognized as playing a well-defined but subsidiary role in this process. However, research within the past five years has established that only 10 to 20% of RNA transcribed from DNA actually serves as a template for proteins.
The function of much of the remaining transcribed RNA is generally unknown. Many of these RNAs are short, with only a few tens of nucleotides, such as microRNA (miRNA). About 1000 different forms of miRNA have beein identified in the human genome, and the effective role of many of these has been discovered.
Longer forms of non-coding RNA, having more that 200 nucleotides, are known simply as long non-coding RNA (lncRNA). Only about 100 have been studied in mammalian tissues so far. The function of only a few of these has been determined. For example, one type is important in regulating stem cells during embryonic development.
Now another lncRNA has been found to play an important role in the maturation of red blood cells.
A long non-coding RNA (lncRNA) regulates programmed cell death during one of the final stages of red blood cell differentiation, according to Whitehead Institute researchers. This is the first time a lncRNA has been found to play a role in red blood cell development and the first time a lncRNA has been shown to affect programmed cell death.