MICOTREM: The Genetic Hack Slime Molds Use to Edit Their Own RNA

In many organisms, DNA sequence is transcribed into RNA and used with minor adjustments. In Physarum, part of the mitochondrial transcript requires active insertion edits to become functional.

That process is often described as MICOTREM (mitochondrial insertional cotranscriptional RNA editing in myxomycetes).

What gets edited

Multiple mitochondrial transcripts contain sites where inserted nucleotides are needed for functional output. Without this editing, many messages remain incomplete for proper protein production.

When it happens

Key point: editing is cotranscriptional in this framework. The transcript is corrected as it is produced, not only in a distant late cleanup step.

Why this is unusual

This mechanism is striking because the scale and insertional behavior differ from many textbook eukaryotic editing examples. It shows that stable biological information flow can include substantial post-template correction logic.

Why readers should care

MICOTREM is not trivia. It is central to mitochondrial function in this lineage. It also reminds us that molecular systems can solve expression constraints with architecture that looks “non-standard” compared with common model organisms.

Related reading: 250 Mb Repeating Genome, Sedolisin Secret, and Taxonomy of a Giant.