A major discovery of the last decade is the unexpected prevalence of atypical RNAs that, unlike mRNAs, do not encode proteins. It is now well established that short non-coding RNAs (ncRNA), including microRNAs, play key roles in the control of development and differentiation. While experimental cases show that some large (>1kb) ncRNAs can contribute as well to various regulatory functions in the control of gene expression, the role and mode of action of most large RNAs that do not encode proteins remains yet poorly understood.
Indeed, most RNAs comprise small Open-Reading-Frames (smORF) that, precisely because of their small size, are generally considered as being non-functional and filtered off from annotations. A growing body of evidence shows, however, that smORF may encode peptides, the abundance of which is probably underestimated. We have recently discovered that the Polished-rice (Pri) small peptides (11-32aa) encoded by an alleged “ncRNA” play a critical role in the control of transcriptional programs during the Drosophila development. These small smORF peptides therefore represent the first case of a novel regulatory mechanism.
Based on accumulated biological tools and an international collaborative network , our research aims at unraveling how smORF peptides control multiple steps of the Drosophila development.