miR-224

miR-224
Conserved secondary structure of miR-224 microRNA precursor
Identifiers
Symbol	miR-224
Alt. Symbols	MIR224
Rfam	RF00680
miRBase	MI0000301
miRBase family	MIPF0000088
Entrez	407009
HUGO	31604
OMIM	300769
RefSeq	NR_029638
Other data
RNA type	miRNA
Domain(s)	Mammalia
GO	0035195
SO	0001244
Locus	Chr. X q28

miR-224 is a family of microRNA precursors found in mammals, including humans. The ~22 nucleotide mature miRNA sequence is excised from the precusor hairpin by the enzyme Dicer.^[1]

Function

miR-224, being located on the X-chromosome, is thought to be active in mammalian ovaries, and possibly responds to TGF beta 1.^[2] A target of miR-224 has been predicted to be SMAD4. Experimental evidence has shown that while the SMAD4 mRNA level is unchanged, increased miR-224 expression decreases concentration of SMDA4 protein in murine granulosa cells.^[3] This is consistent with post-transcriptional miRNA regulation.^[2]

Role in cancer

miR-224 has been noted as the most upregulated microRNA in hepatocellular carcinoma.^[4] The same study identified a target of mir-224 as apoptosis-inhibitor 5 (API-5).^[4]

miR-224 has also been linked with pancreatic ductal carcinoma, where it is thought to repress CD40 expression in cancer cells.^[5]

References

1. ^ Ambros, V (2001 Dec 28). "microRNAs: tiny regulators with great potential.". Cell 107 (7): 823–6. PMID 11779458. 
2. ^ ^{a b} Christenson, LK (2010 Jul 1). "MicroRNA control of ovarian function.". Animal reproduction / Colegio Brasileiro de Reproducao Animal 7 (3): 129–133. PMID 21666774. 
3. ^ Yao, G; Yin, M, Lian, J, Tian, H, Liu, L, Li, X, Sun, F (2010 Mar). "MicroRNA-224 is involved in transforming growth factor-beta-mediated mouse granulosa cell proliferation and granulosa cell function by targeting Smad4.". Molecular endocrinology (Baltimore, Md.) 24 (3): 540–51. PMID 20118412. 
4. ^ ^{a b} Wang, Y; Lee, AT, Ma, JZ, Wang, J, Ren, J, Yang, Y, Tantoso, E, Li, KB, Ooi, LL, Tan, P, Lee, CG (2008 May 9). "Profiling microRNA expression in hepatocellular carcinoma reveals microRNA-224 up-regulation and apoptosis inhibitor-5 as a microRNA-224-specific target.". The Journal of biological chemistry 283 (19): 13205–15. PMID 18319255. 
5. ^ Mees, ST; Mardin, WA, Sielker, S, Willscher, E, Senninger, N, Schleicher, C, Colombo-Benkmann, M, Haier, J (2009 Aug). "Involvement of CD40 targeting miR-224 and miR-486 on the progression of pancreatic ductal adenocarcinomas.". Annals of surgical oncology 16 (8): 2339–50. PMID 19475450.