Kansas City, Mo. (April 23, 2009) – The Stowers Institute’s Washburn Lab has collaborated with the Workman Lab to shed light on the role of the Rtr1 protein on the regulation of the RNA-producing enzyme RNA Polymerase II (Pol II) during transcription. The work was published today by Molecular Cell.

     Transcription is the first step in gene expression, and it involves the construction of an RNA molecule using a DNA molecule as a template. Pol II is responsible for transcription of messenger RNA (mRNA) that is then used for protein production during translation. The team investigated the role of Rtr1 on transcription and found that it regulates the metabolic process known as phosphorylation — the addition of a phosphate group to a protein molecule.

     Pol II is an enzyme composed of many different proteins that work together. One of these proteins, Rpb1, has a unique end made up of a repeating chain of amino acids called the carboxy-terminal domain (CTD), which is involved in the initiation of transcription and the regulation of mRNA processing.

     Rtr1 was previously known to interact with Pol II, but until now, its role in regulating transcription had not been described. This work has shown that Rtr1 regulates the phosphorylation of Pol II during the early stages of the transcription cycle, when phosphorylation of the amino acid serine 5 on the CTD is normally high.

     To study the impact of Rtr1, the team deleted the protein from yeast cells. They observed an increase in the levels of serine 5, especially toward one end of the gene — the 3’ end — which suggests that Rtr1 regulates the removal of phosphate groups from serine 5.

     Dephosphorylation of serine 5 is an essential step in the elongation stage of transcription, but until the Washburn Lab published this work, no proteins were known to specifically target serine 5 for dephosphorylation in the coding region of genes.

     “The process of transcription and the interaction between Rtr1 and Pol II is very similar across species — from yeast to humans,” said Amber Mosley, Ph.D., Senior Research Associate and first author on the paper. “Based on this work, we believe that Rtr1 likely plays a role in the regulation of the Pol II transcription cycle in higher organisms.”

     “Understanding the function of Rtr1 will allow us to further examine its role in the phosphorylation of Pol II and to understand the biological effects of serine 5 CTD hyperphosphorylation,” said Michael Washburn, Ph.D., Director of Proteomics Center and senior author on the publication. “This was an excellent collaboration with the laboratory of Jerry Workman — it was our work together that made this discovery possible.”

     Additional contributing authors from the Stowers Institute include Samantha Pattenden, Ph.D., Senior Research Associate; Michael Carey; Swaminathan Venkatesh, Ph.D., Postdoctoral Research Associate; Joshua Gilmore, Ph.D., Postdoctoral Research Associate; Laurence Florens, Ph.D., Managing Director of Proteomics; and Jerry Workman, Ph.D., Investigator.

     Michael Washburn, Ph.D., Director of Proteomics Center, joined the Stowers Institute in 2003 from the Torrey Mesa Research Institute in San Diego. Learn more about his work at www.stowers.org/labs/WashburnLab.asp.

About the Stowers Institute for Medical Research
     Housed in a 600,000 square-foot state-of-the-art facility on a 10-acre campus in the heart of Kansas City, Missouri, the Stowers Institute for Medical Research conducts basic research on fundamental processes of cellular life. Through its commitment to collaborative research and the use of cutting-edge technology, the Institute seeks more effective means of preventing, treating, and curing disease. Jim and Virginia Stowers endowed the Institute with gifts totaling $2 billion. The endowment resides in a large cash reserve and in substantial ownership of American Century Investments, a privately held mutual fund company that represents exceptional value for the Institute’s future.