Chasing the Ghost Proteome in the Dark Matter.

Area of Science:

• Genomics
• Proteomics
• Molecular Biology

Background:

• Noncanonical open reading frames (ORFs) produce biologically active proteins.
• These proteins, termed microproteins or small proteins, originate from 5'/3' UTRs, lncRNAs, overlapping frames, or pseudogenes.
• They can initiate at non-AUG start codons and regulate cellular processes like metabolism and epigenetics.

Purpose of the Study:

• To introduce and define the concept of the "ghost proteome."
• To distinguish the ghost proteome from the "dark proteome."
• To highlight the implications of recognizing the ghost proteome for genome annotation and biological discovery.

Main Methods:

• Literature review and conceptual synthesis.
• Analysis of emerging evidence on noncanonical ORF translation.
• Comparative definition of ghost and dark proteomes.

Main Results:

• The ghost proteome comprises functional proteins translated from noncanonical ORFs.
• This proteome originates from genomic regions previously considered non-coding or "junk."
• The ghost proteome is distinct from the dark proteome (unannotated regions of canonical proteins).

Conclusions:

• Recognizing the ghost proteome expands the definition of protein-coding sequences.
• This concept necessitates harmonized nomenclature and database integration for systematic discovery.
• The ghost proteome offers new avenues for investigating biology and disease by re-evaluating genome annotation.