Pervasiveness of Microprotein Function Amongst Drosophila Small Open Reading Frames (SMORFS)

Area of Science:

• Genomics
• Proteomics
• Molecular Biology

Background:

• Small Open Reading Frames (smORFs), defined as <100 codons, are largely uncharacterized in metazoans.
• Short Coding Sequences (sCDSs) encode peptides/microproteins (70-80 aa) with potential structures and translation markers.
• Genome-wide functional studies in yeast/bacteria show sCDSs can impact phenotypes, but metazoan efforts are limited.

Purpose of the Study:

• To detect and corroborate the function of sCDSs in Drosophila using integrated experimental and computational approaches.
• To expand the repertoire of characterized smORFs and their encoded peptides/microproteins.
• To investigate the relationship between sCDS function and bioinformatic features.

Main Methods:

• Combined proteomics, bioinformatics, and genetics in Drosophila.
• Extensive proteomic analysis to detect peptides and microproteins from sCDSs.
• Bioinformatic analysis including conservation and GC content assessment.

Main Results:

• Nearly doubled the number of sCDSs with detected peptides/microproteins and experimentally corroborated function.
• Identified a correlation between proven sCDS protein function and bioinformatic markers (conservation, GC content).
• Observed that sCDS peptides/microproteins function as membrane-related regulators of canonical proteins.

Conclusions:

• sCDSs encode functional peptides and microproteins, often acting as regulators at the cellular level.
• The function of smORF-encoded proteins is often subtle, not leading to overt morphological phenotypes.
• Bioinformatic markers can predict functional sCDSs, aiding future characterization efforts.