Retrotransposons and piRNA: the missing link in central nervous system.

From times when the whole genome were not available to the present explosion of genome knowledge, the biology of non-coding RNA molecules are an unknown ocean of gems. One among them are PIWI-interacting RNAs (piRNAs) that restrict the mobility of various retrotransposons. PIWI proteins and piRNAs once thought to be germline specific was now explored to be expressed in different somatic cells. Emerging proofs of piRNAs from central nervous system has raised serious questions regarding the role of retrotransposons and its silencing mechanism. In this review, we have focused on the existing knowledge of retrotransposons and piRNAs in the central nervous system and have provided future insights. Meta-analysis of retrotransposons in various mammalian genomes and piRNA targets showcased the abundance of LINE transposon and the possibility of piRNA mediated retrotransposon expression. Thus, understanding the retrotransposons-piRNA pathway will provide a new vision for the study of development, physiology and pathology of the central nervous system.