Some microRNAs (miRNAs) molecules are assumed to control cell growth, development, and stress response. Investigators from the Tufts University School of Medicine and Tufts Medical Center claim to have found an RNA sequence that boosts the number of such miRNAs. The results have helped scientists to determine the probable link between miRNA expression and diseases like heart disease and cancer.
Investigators elucidate MiRNAs to initially form as a long sequence of RNA known as the primary miRNA. Scientists believe this molecule to undergo several steps for transforming into mature miRNA. The mature miRNAs possibly control gene expression by silencing or activating target genes. At present researchers are apparently aware about more than 700 human miRNAs with various functions. In a prior investigation it was ascertained that certain miRNAs are controlled in response to cellular signals from a specific signaling pathway.
“A growing body of evidence shows that abnormal expression of miRNAs can contribute to human diseases such as heart disease and cancer. A better understanding of how miRNAs are generated and how they regulate genes may provide important insights into the mechanisms of physiological disorders such as heart disease and cancer,” shared Akiko Hata, PhD, associate professor in the department of biochemistry at Tufts University School of Medicine (TUSM) and a member of the biochemistry and cell, molecular and developmental biology program faculties at the Sackler School of Graduate Biomedical Sciences at Tufts and the senior investigator.
During the current investigation, experts supposedly discovered that most of the miRNAs controlled by this signaling pathway have a common RNA sequence. On mutation of this RNA sequence, the signaling pathway seemed to no longer regulate miRNA processing. To the contrary, when the RNA sequence was introduced into a new miRNA, the miRNA appeared responsive to the signaling pathway.
Brandi Davis, PhD, a graduate of the biochemistry program at the Sackler School, a postdoctoral fellow in Hata’s lab and the first investigator remarked, “An enzyme called Drosha is needed for miRNA processing. Our previous studies determined that proteins called Smads are also required for the processing of some miRNAs in response to cellular signals. Now, we have identified the RNA sequence that recruits Drosha and Smads for miRNA processing in response to the signaling pathway. We knew that Smad proteins regulate gene expression by binding to DNA. Our current study is exciting because it shows that Smads play an additional role, controlling miRNA expression by binding to the structurally different RNA.”
Currently, researchers are working to determine the way miRNA expression is regulated. They also aim to find the genes that are targeted by miRNAs and the correlation between varying levels of miRNAs and human disease especially heart disease and cancer. Understanding the mechanisms managing which genes are translated and which genes are silenced, can possibly explain the impact of miRNAs in the progression of cardiovascular diseases and cancer.
The research was published in the August 13 issue of Molecular Cell.