MicroRNAs （miRNAs） are endogenously expressed small, non-coding transcripts that regulate protein expression. Substantial evidences suggest that miRNAs are enriched in central nervous system, where they are hypothesized to play pivotal roles during neural devel- opment. In the present study, we analyzed miRNAs expression in mice cerebral cortex and hippocampus at different developmental stages and found miR-29a increased dramatically at postnatal stages. In addition, we provided strong evidences that miR-29a is enriched in mature neurons both in vitro and in v/vo. Further investigation demonstrated that the activation of gluta- mate receptors induced endogenous miR-29a level in primary neurons. Moreover, we showed that miR-29a directly regulated its target protein Doublecortin （DCX） expression, which further modulated axon branching in primary culture. Together, our results suggested that miR-29a play an important role in neuronal development of mice cerebrum.
Hanqin LiSusu MaoHaitao WangKe ZenChenyu ZhangLiang Li
SMALL RNA IN REVERSE TRANSCRIPTASE： TOO SMALL TO BE FOUND Significant background in no-template or no-primer RT-PCR is frequently noted. However, the underlying mechanism is still unclear. In this issue, Jie Xu and colleagues reveal that the com- mercial reverse transcriptases contain small RNAs. In AMV reverse transcriptase, they detected microRNAs derived from the virus host chick or other birds. This surprising finding at least partially explains the high background in some AMV reverse transcriptases based RT-PCR.
Jie Xu Xi Chen Donghai Li Qun Chen Zhen Zhou Dongxia Hou Jin Wang Qipeng Zhang Ke Zen Chen-Yu Zhang
