Question

You have discovered that a particular mRNA of GeneX in maize is required for the regulation of GeneY. However, this mRNA does not encode any proteins, yet in its absence the levels of protein Y (product of GeneY) are significantly increased. Propose one likely mechanism for how GeneX may be controlling the levels of Protein Y.

Answer 1

The product of Gene X appears to be a non-coding RNA (ncRNA), more specifically a long non-coding RNA (lncRNA).

A non-coding RNA (ncRNA) is a functional RNA molecule that is transcribed from DNA but not translated into proteins. Epigenetic related ncRNAs include miRNA, siRNA, piRNA and lncRNA. In general, ncRNAs function to regulate gene expression at the transcriptional and post-transcriptional level.

Many lncRNAs can complex with chromatin-modifying proteins and recruit their catalytic activity to specific sites in the genome, thereby modifying chromatin states and influencing gene expression. The majority of non-coding RNA transcripts belong to the group lncRNAs. Long ncRNAs function in chromatin remodeling, transcriptional regulation, post-transcriptional regulation, and as precursors for siRNAs.