Structural basis of the nucleosome transition during RNA polymerase II passage

Catching gene transcription in the act

27 May 2019

Enzymes that convert DNA into RNA need to navigate around structural units of the chromosome. A Japanese study now shows how.

In eukaryotes, DNA is packaged as chromatin, in which spool-like structures known as nucleosomes form the basic unit. During transcription of DNA into RNA, an enzyme known as RNA polymerase II has to negotiate nucleosomes, but the details of how it achieves this have been unclear until now.

A team co-led by scientists from Waseda University has now used cryo-electron microscopy to take serial molecular snapshots of RNA polymerase II interfacing with nucleosomes.

The researchers found that the enzyme pauses at specific sites where DNA contacts the structural proteins. Then, in a stepwise fashion, it peels off the DNA before decoding the gene sequence into RNA transcripts.

The study offers an unprecedented level of insight into how genetic information gets read inside cells, and offers a foundation for future investigations of how other molecules contribute to this process.

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References

1. Science 362, 595–598 (2018). doi: 10.1126/science.aau9904