Abstract: miRNAs are a kind of endogenous, non-coding RNA of about 22 nucleotides in length, which can regulate the target gene expression at post-transcriptional level by trimming the transcript or repressing the translation. Plenty of studies showed that miRNAs in animals played important roles in animal developmental process, such as early embryonic development, brain and neurological development, cardiac development, bone and muscle development and so on. There are evidences demonstrating that some miRNAs are specifically expressed in placenta and play an important role in placental normal development. Therefore, we gave a key reference to miRNAs involved in placental development in this article.

Key words: miRNA; placenta; regulator; development