miR-30 microRNA precursor is a small non-coding RNA that regulates gene expression. Animal microRNAs are transcribed as pri-miRNA (primary miRNA) of varying length which in turns are processed in the nucleus by Drosha into ~70 nucleotide stem-loop precursor called pre-miRNA (precursor miRNA) and subsequently processed by the Dicer enzyme to give a mature ~22 nucleotide product. In this case the mature sequence comes from both the 3' (miR-30) and 5' (mir-97-6) arms of the precursor. The products are thought to have regulatory roles through complementarity to mRNA. A screen of 17 miRNAs that have been predicted to regulate a number of breast cancer associated genes found variations in the microRNAs miR-17 and miR-30c-1, these patients were noncarriers of BRCA1 or BRCA2 mutations, lending the possibility that familial breast cancer may be caused by variation in these miRNAs. Members of the miR-30 family have been found to be highly expressed in heart cells.

Targets of miR-30

It has been shown that the integrin ITGB3 and the ubiquitin conjugating E2 enzyme UBC9 are downregulated by miR-30. It has also been suggested that the TP53 protein may be a target of miR-30c and miR-30e. An immunoblot analysis revealed that p53 expression levels were elevated upon knockdown of miR-30c and miR-30e.