A new discovery based on research using The Hormel Institute’s powerful electron microscope – the CryoEM – was published by Dr. Bin Liu, head of the Transcription and Gene Regulation lab. Dr. Liu’s research offers new understanding of how an important process in gene transcription works.

Gene transcription is the process in which DNA is copied into RNA, allowing the gene to create things like proteins that do jobs in our bodies. Transcription activation is the process that increases gene transcription of some genes. Cyclic AMP receptor protein (CAP) is a major transcription activator.

Although CAP has been studied for decades, it is still unclear whether and how CAP remodels RNA polymerase (RNAP) to activate transcription. RNA polymerase is an enzyme that does the work of copying DNA into RNA during gene transcription.

Using cryo-EM, Dr. Liu and his team have captured an on-pathway intermediate state with significant changes to the shape of the protein during transcription activation. The structural information gained in this study suggests a unique CAP-induced activation mechanism that significantly widens the main cleft of RNAP. This makes it easier for DNA promoter to enter into the cleft and form the open promoter complex, where the double strand of DNA is unwound so it can be transcribed.

Dr. Liu’s article, “Visualization of two architectures in class-II CAP-dependent transcription activation” was published in the prestigious top journal PLOS Biology. PLOS Biology is the flagship PLOS journal in the life sciences and features works of exceptional significance, originality, and relevance in all areas of biological science.

Thanks to the support of The Hormel Foundation, The Hormel Institute’s CryoEM lab was established in 2016 with the acquisition of a Titan Krios II cryo-electron microscope. There is a growing team of researchers using the CryoEM technology, which allows researchers to see the structure of cells and even structures within the cells, to the near-atomic level.