Signal peptides restrict genome evolution and A-to-I RNA editing.

Area of Science:

• Genomics
• Molecular Biology
• Evolutionary Biology

Background:

• Genetic information flows from DNA to RNA to protein.
• Highly conserved genomic sequences are often thought to be compensated by post-transcriptional mechanisms like alternative splicing (AS) and RNA editing to enhance molecular diversity.
• Signal peptides are short N-terminal sequences directing protein localization.

Purpose of the Study:

• To investigate the relationship between signal peptides and post-transcriptional regulation.
• To determine if signal peptide-encoding genes exhibit reduced transcriptomic diversity.
• To explore the constraints signal peptides impose on genomic evolution and RNA-based regulatory mechanisms.

Main Methods:

• Analysis of genomes and transcriptomes from *Drosophila melanogaster* and other species.
• Comparative analysis of protein isoform production in genes with and without signal peptides.
• Assessment of alternative splicing and RNA recoding events in signal peptide regions.

Main Results:

• Genes encoding signal peptides produce significantly fewer protein isoforms compared to genes without.
• Alternative splicing events are underrepresented in the N-terminal regions of signal peptide-containing genes.
• RNA recoding events are notably avoided in signal peptide regions in both fruitflies and humans.

Conclusions:

• The presence of signal peptides imposes constraints on genomic evolution and transcriptomic diversity.
• Conserved genomic elements, such as signal peptides, do not always correlate with increased post-transcriptional diversification.
• This study provides new insights into the evolutionary principles governing RNA-based regulatory mechanisms and genome conservation.