Description(s):

A polycistronic miRNA cluster miR-17-92 plays a role in the control of cell proliferation and angiogenesis. This cluster consists of seven miRNAs: miR-17-5p, miR-17-3p, miR-18a, miR-19a, miR-19b, miR-20a, and miR-92. Like E2F1 gene, the cluster is transcriptionally activated by the proto-oncogene c-Myc. Because two of the expressed miRNAs, miR-17-5p and miR-20a, repress the translation of E2F1, the level of E2F1 protein is modulated by this feedback mechanism.  Therefore, the accumulation of excessive amounts of E2F1 can be prevented and the states of cells towards apoptosis or cell division can be controlled. In addition, c-MYC-mediated induction of the miR-17-92 cluster results in down-regulation of the anti-angiogenic thrombospondin-1 and related proteins, such as connective tissue growth factor 2; Therefore, it promotes angiogenesis.  Furthermore, a recent study indicates that the cluster is significantly up-regulated at the clonal expansion stage of adipocyte differentiation. The miR-17-92 cluster has been implicated as the oncogenes in numerous tumor types.  Effective monitoring of the expression of the clustered miRNAs can help us better understand how the alteration of the cluster contributes to development of cancers and shed light on the molecular mechanisms of miRNA function.

Principle

In the proprietary miRNA plate assay, one miRNA molecule is flanked by a capture oligo and a biotinated detection oligo through two bridges oligos. One of the bridge oligos is partially hybridized with the miRNA molecule and the capture oligo and another with the miRNA and the detection oligo. The hybrid is immobilized onto plate through hybridization with an immobilized oligo and detected by a streptavidin-HRP conjugate and chemiluminecscent substrate. This hybrid structure is sensitive to the sequence of the miRNA molecule. One nucleotide difference will prevent the formation of the hybrid and therefore miRNA isoform can be differentiated, which normally is hard to tackle with Northern blot. In addition, the sensitivity of the assay is higher than miRNA Northern blot assay.

Data

Expression of miR-17-92 cluster was analyzed with o.5ug of total RNA prepared from HeLa and 293 cells through miR-17-92 cluster plat assay. Among the assays, HeLa total RNA was analzyed three times.

Literature

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Citations

1. Transcription factor C/EBP-β induces tumor-suppressor phosphatase PHLPP2 through repression of the miR-17–92 cluster in differentiating AML cells, Y Yan, E A Hanse, K Stedman, J M Benson, X H Lowman, S Subramanian and A Kelekar, Cell Death & Differentiation, 2016 doi:10.1038/cdd.2016.1
 
2. Transcription factor C/EBP-β induces tumor-suppressor phosphatase PHLPP2 through repression of the miR-17–92 cluster in differentiating AML cells. Y Yan, EA Hanse, K Stedman, JM Benson, XH Lowman. Cell Death & Differentiation, (12 February 2016) | doi:10.1038/cdd.2016.1