BOSTON (August 16, 2010) Researchers at Tufts University School of Medicine and Tufts Medical Center have identified an RNA sequence that promotes increased numbers of specific microRNAs (miRNAs), molecules that regulate cell growth, development, and stress response. The discovery helps researchers understand the links between miRNA expression and disease, including heart disease and cancer. The findings are published in the August 13 issue of Molecular Cell.
"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," said senior author 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.
MiRNAs are initially formed as a long sequence of RNA called the primary miRNA. This molecule undergoes several steps to transform it into mature miRNA. Once formed, the mature miRNAs regulate gene expression by silencing or activating target genes. More than 700 human miRNAs with various functions are currently known.
Hata and colleagues previously found that the processing of some miRNAs could be regulated in response to cellular signals from a specific signaling pathway. In the current study, Hata and colleagues found that most of the miRNAs regulated by this signaling pathway share a common RNA sequence. When this RNA sequence was mutated, the signaling pathway no longer regulated miRNA processing. Conversely, when the RNA sequence was introduced into a new miRNA, the miRNA became responsive to the signaling pathway.
"An enzyme called Drosha i
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Tufts University, Health Sciences