The study by Liu et al. indicates that microRNAs function as powerful regulators of post-transcriptional gene regulation in the adult and aging brain. The paper neatly demonstrates that when several newly identified targets of miR-34 escape regulation, late-onset brain degeneration ensues. Using the Drosophila
fly as a model system, the authors could demonstrate that flies lacking miR-34 were born with no obvious defects; however, with aging these flies developed motoric dysfunction and brain degeneration.
These interesting and timely observations build on a recent body of evidence that implicates microRNAs as important molecular components of a healthy aging process.
This paper has identified some exciting and novel targets of miR-34 regulation that may be conserved. However, the targets of individual microRNAs can number in the hundreds to thousands. Indeed, this paper has identified E74A-dependent and E74A-independent pathways to disease in the absence of miR-34.
Drosophila flies expressing a polyQ disease protein (ataxin-3 polyglutamine) exhibit...