Non-human lnc-DC orthologs encode Wdnm1-like protein

Area of Science:

• Immunology
• Molecular Biology
• Evolutionary Biology

Background:

• A recent study identified a long noncoding RNA (lncRNA) termed lnc-DC in human dendritic cells (DCs).
• The study proposed lnc-DC's crucial role in monocyte differentiation into DCs based on RNA interference (RNAi) experiments.
• The identified mouse ortholog was previously known as Wdnm1-like, encoding a secreted protein.

Purpose of the Study:

• To re-evaluate the function of the human lnc-DC transcript in light of its evolutionary history.
• To question the interpretation of RNAi experiments regarding lnc-DC's role in dendritic cell differentiation.
• To highlight potential off-target effects and alternative hypotheses concerning the lnc-DC locus.

Main Methods:

• Comparative genomics analysis of the Wdnm1-like locus across mammals.
• Review and critique of RNA interference (RNAi) methodologies used in the original study.
• Analysis of potential off-target effects of RNAi in dendritic cell differentiation studies.

Main Results:

• The Wdnm1-like open reading frame (ORF) is conserved in most mammals, with exceptions in hominids, suggesting the human lnc-DC may be a non-functional remnant.
• The original study's RNAi experiments lacked comprehensive analysis of off-target effects, potentially confounding results.
• The Wdnm1-like locus might have evolved distinct functions for its transcript and protein products.

Conclusions:

• The human lnc-DC transcript may represent a non-functional remnant of an ancient protein-coding gene.
• The functional significance of lnc-DC in dendritic cell differentiation requires further investigation, considering potential off-target effects.
• The Wdnm1-like locus presents an intriguing case of potential dual functionality (transcript and protein) in cell maturation across evolution.