RNA Protects “Naked” Genomes from Retrotransposons

Transfer RNA fragments prevent jumping genes from hopping around in the mouse embryo, when histone methylation can’t do the job.

Shawna Williams
Shawna Williams

Shawna joined The Scientist in 2017 and is now a senior editor and news director. She holds a bachelor's degree in biochemistry from Colorado College and a graduate certificate and science communication from the University of California, Santa Cruz.

View full profile.


Learn about our editorial policies.

WIKIMEDIA, MARIUSWALTERTo protect their genes from being wrecked by retrotransposons, or jumping genes, mouse cells usually employ histone methylation to stop these rogue genetic elements from being transcribed. But how does the genome stay protected in the pre-implantation embryo, when methyl groups are temporarily stripped from cells’ DNA. A new study, published yesterday (June 29) in Cell, finds tRNA fragments are key.

Based on previous studies in fruit flies, Andrea Schorn and Rob Martienssen of Cold Spring Harbor Laboratory thought the answer to what protects vulnerable mouse embryo genomes might lie in small RNAs. To find them, they made some tweaks to the usual techniques. As they explain in their paper, “many small RNA sequencing studies omit RNA fragments shorter than 19 [nucleotides] or discard sequencing reads that map to multiple loci in the genome, thus often discarding reads matching young, potentially active transposons…” 

By including smaller fragments...

See “Tethering transposons”      

“It’s plausible that this is a very ancient mechanism that cells have found to not only inhibit retrotransposons but help in protection against viruses as well,” Martienssen says in a statement.

Interested in reading more?

The Scientist ARCHIVES

Become a Member of

Receive full access to more than 35 years of archives, as well as TS Digest, digital editions of The Scientist, feature stories, and much more!
Already a member?