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GEN (Jul. 19, 2012) While it remains too early to tell whether microRNAs (miRNAs) will ultimately prove clinically useful, preclinical research findings continue to confirm their central role in controlling cellular pathways. his novel class of nucleotides, about 20-25 nucleotides in length, affects gene expression by interacting with messenger RNAs. But unlike siRNAs, miRNAs are encoded in the human genome and function as natural regulators of global gene expression. John F. McDonald, Ph.D., professor, associate dean for biology program development, CSO Ovarian Cancer Institute, and colleagues at the Georgia Institute of Technology separately transfected two miRNAs (miR-7 and miR-128) into the ovarian cancer cell line (HEY) and then monitored global changes in gene expression levels. While 20% of the changes in expression patterns of hundreds to thousands of genes could be attributed to direct miRNA-mRNA interactions, they reported, the majority of the changes were indirect, involving the downstream consequences of miRNA-mediated changes in regulatory gene expression. The pathways most significantly affected by miR-7 transfection, the investigators said, are involved with cell adhesion and other developmental networks previously associated with epithelial-mesenchymal transitions and other processes linked with metastasis. (full story..) |