mir-29 microRNA precursor
| mir-29 microRNA precursor | |
|---|---|
| SO | SO:0001244 |
| PDB structures | PDBe |
The miR-29 microRNA precursor, or pre-miRNA, is a small
miRNA processing
Animal miRNAs are first transcribed as a primary miRNA molecule. This "pri-miRNA" may contain one or more precursor hairpins, which are freed from the pri-miRNA by the nuclear enzyme Drosha. The approximately 70 nucleotide precursor hairpin is exported from the nucleus and subsequently processed by the Dicer enzyme to give a mature miRNA that is on average 22 nucleotides long. Either arm of the precursor may yield a mature RNA, although either the 3' (3p) or the 5' (5p) arm is preferentially processed and loaded into the RNA-induced silencing complex (RISC) in most cases. For the miR-29 precursor, the 3' arm of the precursor RNA yields the overwhelmingly predominant product (miR-29 or miR-29-3p), although the 5' arm (miR-29* or miR-29-5p) has also been experimentally verified.
The miR-29 family
Many mammalian genomes encode four closely related miR-29 precursors that are transcribed in two transcriptional units. For example, human miR-29a and miR-29b-1 are processed from an intron of a long non-coding transcript (LOC646329) from chromosome 7. miR-29b-2 (identical in sequence to miR-29b-1) and miR-29c are co-transcribed from chromosome 1. The three main mature miRNAs processed from these precursors are known as hsa-miR-29a, hsa-miR-29b, and hsa-miR-29c.
Survival analysis across three independent datasets shows that hsa-miR-29c is associated with survival in breast cancer.[2]
Targets of miR-29
The mature products are thought to exert regulatory roles by binding with partial complementarity to microRNA recognition elements (MREs) in the 3' untranslated region (3' UTR) of target transcripts. Experimental evidence suggests that putative targets of mature miR-29 products include the following:
- The myeloid leukemia cell differentiation protein (MCL1),[3] an anti-apoptotic member of the Bcl-2 family of proteins.
- The leukemias, but also dysregulated B cell malignancies.
- Zinc finger protein 36 homolog (ZFP36),[6] also known as tristetraprolin (TTP), an anti-inflammatory and anti-cancer gene.[7]
- tumor necrosis factor receptor-associated factor 4 (TRAF4) was identified as miR-29 target in B cells, and as a regulator of CD40 signalling
Recently, in an attempt to identify targets at global level using
References
Further reading
- Zhang X, Zhao X, Fiskus W, Lin J, Lwin T, Rao R, Zhang Y, Chan JC, Fu K, Marquez VE, Chen-Kiang S, Moscinski LC, Seto E, Dalton WS, Wright KL, Sotomayor E, Bhalla K, Tao J (Oct 2012). "Coordinated silencing of MYC-mediated miR-29 by HDAC3 and EZH2 as a therapeutic target of histone modification in aggressive B-Cell lymphomas". Cancer Cell. 22 (4): 506–23. PMID 23079660.
External links