Invitational Seminars

Rewriting the message: RNA regulation in cephalopods, aging vertebrates, and bacteria

Once a gene is transcribed, its message is not fixed. RNA can be edited at the sequence level, rearranged into distinct isoforms, or read with varying efficiency, and different branches of life emphasize these layers unequally.

In soft-bodied cephalopods, one such route is unusually pervasive: A-to-I RNA editing. By changing individual nucleotides in mature transcripts, editing can recode protein sequences, and it does so far more extensively here than in most animals. Squid, octopus, and cuttlefish therefore offer a striking system for asking which recoding events are tolerated, which may be shaped by selection, and whether neighboring editing sites are coupled into coordinated patterns along the same transcript.

A second eukaryotic route is alternative splicing. By combining exons differently, cells build distinct isoforms from one gene. During aging, splicing patterns shift across tissues and species, raising the question of which changes reflect general features of aging and which arise from tissue identity, changing cell composition, or transcriptomic noise.

Bacteria strike a different regulatory balance. With limited editing and no spliceosomal splicing, much of their post-transcriptional control acts as the message is read: short features near translation start sites, including leading codons and Shine-Dalgarno spacing, can strongly tune protein output.

Together, these systems show how RNA regulation expands the meaning of a gene, letting sequence, isoform choice, and translation efficiency shape biological output.