Researchers have a deeper understanding of a large switch/sucrose nonfermentable (SWI/SNF) protein complex that plays a pivotal role in plant and human gene expression that causes life-threatening diseases such as cancer. A team of scientists in the department of biochemistry and biophysics and Institute for Plant Genomics and Biotechnology at Texas A&M University in College Station. The study was published in the journal Nature.

Their findings could lead to more targeted therapies and help with physiological improvements in both crops and animal agriculture. The work may provide a new idea to manipulate the functions of this protein for a better therapeutic strategy for curing human cancers. The team has been working for years on how microRNAs are produced in the model plant Arabidopsis. MicroRNAs are tiny regulatory RNA molecules widely present in multicellular organisms.

In humans, microRNAs inhibit more than 60% of human genes and are actively exploited as potent drugs to cure human diseases. They are interested in finding whether there are other workers in the factory. Thus Serrate protein as fishing bait to catch the prey, and we caught chromatin-remodeling factor 2 (CHR2).CHR2 is a SWI2/SNF2 motor protein with ATPase activity.

The team began to search where the disorders take place. After a series of tests, they eventually found the shapes of the microRNA substrates are changed; and the scissor enzyme cannot cut the substrates anymore. The results are significant because they provide an additional unknown layer of microRNA level regulation. For the first time, an explanation is provided for many earlier reports showing that the level of microRNA substrates in many cases does not reflect the amount of mature microRNA.

The study is novel and exciting. It shows that the secondary structure of microRNA substrates contains a new informational code that needs to be interpreted by CHR2 and Serrate proteins. CHR2 ATPase and its associated partners in the SWI/SNF complex are immensely implicated in numerous physiological disorders and diseases in plants and human. The work identifies a unique gene-editing target to control microRNA amount for systematically improving agricultural traits such as plant architecture, yield, quality and response to hostile environments.

In human the SWI/SNF complex has been known as a potent tumor suppressor. In fact, mutations in SWI/SNF components have been found to occur at a frequency of greater than 20% across a spectrum of human cancers.