Alteration of microRNA expression in the process of mouse brain growth.

MicroRNAs (miRNAs) are a functional small non-coding RNA and play essential roles in gene regulation in development, differentiation and proliferation. In this study, we investigated expression profiles of miRNAs in the process of normal mouse brain growth from embryonic day 16.5 to ~19 months old by means of DNA microarray and reverse-transcription quantitative polymerase chain reaction, and we examined whether there was any association between the expression of miRNAs and brain growth. The results indicated that a major change in the expression of miRNAs occurred in the brain within the first week to the fourth week postnatally. The data also exhibited the miRNAs that gradually increased and decreased in their levels, over the course of brain growth. Therefore, the current study suggests that miRNAs are capable of becoming a useful biological marker for study of brain growth, and leads to the possibility that gene silencing involving miRNAs may participate in the process of brain growth and perhaps brain aging.