MIR21

Summary

MIR21 (microRNA 21, HGNC:31586) is a microRNA gene on chromosome 17q23.1.

microRNAs (miRNAs) are short (20-24 nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. miRNAs are transcribed by RNA polymerase II as part of capped and polyadenylated primary transcripts (pri-miRNAs) that can be either protein-coding or non-coding. The primary transcript is cleaved by the Drosha ribonuclease III enzyme to produce an approximately 70-nt stem-loop precursor miRNA (pre-miRNA), which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA and antisense miRNA star (miRNA*) products. The mature miRNA is incorporated into a RNA-induced silencing complex (RISC), which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. The RefSeq represents the predicted microRNA stem-loop.

Source: NCBI Gene 406991 — RefSeq curated summary.

At a glance

• Gene type: non-coding (miRNA) — no protein product; not a drug target. Variant/disease associations are omitted (they would be positional, from an overlapping protein-coding gene).

Identifiers

Gene identifiers

Field	Value
HGNC ID	HGNC:31586
Approved symbol	MIR21
Name	microRNA 21
Location	17q23.1
Locus type	RNA, micro
Status	Approved
Aliases	hsa-mir-21, MIR-21
Ensembl gene	ENSG00000284190
Ensembl biotype	miRNA
OMIM	611020
Entrez	406991
RNAcentral	URS00000AF93C — miRNA, 72 nt, 32 organism(s)

Gene structure

Transcript identifiers

Ensembl transcripts: 1 — 1 miRNA

ENST00000362134

RefSeq mRNA: 0 — MANE Select: None

Canonical transcript exons

ENST00000362134 — 1 exons

Exon	Start	End
ENSE00001436897	59841266	59841337

Expression profiles

Bgee: expression breadth broad, 12 present calls, max score 98.84.

Top tissues by expression

12 total, by Bgee expression score (0-100, higher = more expressed):

Tissue	Anatomy ID	Expression score	Quality
renal glomerulus	UBERON:0000074	98.84	gold quality
prostate gland	UBERON:0002367	96.43	gold quality
spleen	UBERON:0002106	78.87	gold quality
pituitary gland	UBERON:0000007	78.24	gold quality
uterus	UBERON:0000995	76.45	gold quality
epididymis	UBERON:0001301	74.12	gold quality
islet of Langerhans	UBERON:0000006	61.87	gold quality
ovary	UBERON:0000992	61.52	gold quality
thyroid gland	UBERON:0002046	59.18	gold quality
placenta	UBERON:0001987	57.00	gold quality
midbrain	UBERON:0001891	56.50	silver quality
liver	UBERON:0002107	51.87	silver quality

Single-cell (SCXA)

Detected in 1 experiment(s), a significant marker in 0.

Experiment	Marker?	Max mean expression
E-ANND-3	no	0.00

Regulation

Is transcription factor: no

Upstream regulators (CollecTRI, top): AP1, BCL6, ETV4, FOS, FOXO3, GRHL3, NANOG, NFKB, PPARA, PRDM1, RARA, RELA, REST, SRF, STAT3

Literature-anchored findings (GeneRIF, showing 40)

• miR-21 is upregulated in papillary thyroid carcinoma. (PMID:16365291)
• miRNAs are aberrantly expressed in the vascular walls after balloon injury.Modulating an aberrantly overexpressed miRNA, miR-21, via antisense-mediated depletion (knock-down) had a significant negative effect on neointimal lesion formation. (PMID:17478730)
• miR-21 was significantly upregulated in both psoriasis and atopic eczema as compared with healthy skin. It was expressed by both structural and inflammatory cells of the skin. (PMID:17622355)
• Aberrant expression of miR-21 can contribute to hepatocellular carcinoma growth and spread by modulating PTEN expression and PTEN-dependent pathways. (PMID:17681183)
• miR-21 induces invasion/intravasation/metastasis. (PMID:17968323)
• miR-21 links hypoxia with cell cycle regulation and is deleted in human epithelial ovarian cancer. (PMID:18059191)
• for the first time, we have shown that expression of miR-21 positively correlates with clinical stage, lymph node positivity and the development of distant metastasis in patients with CRC. (PMID:18196926)
• Alterations in miRNA-21 expression levels or function may be involved in dysregulation of angiotensin II signaling and abnormal aldosterone secretion by adrenal glands in humans. (PMID:18218696)
• mir-21 functions as an oncogene by a mechanism that involves translational repression of the tumor suppressor Pdcd4 (PMID:18372920)
• Since exogenous miR-21 expression moderately induced endogenous miR-21, an evolutionarily conserved double-negative feedback regulation would be operating as a mechanism to sustain miR-21 expression. (PMID:18384814)
• miR-21 was overexpressed in 92% (34/37) of the gastric cancer samples examined (PMID:18507035)
• miR-21 contributes to glioma malignancy by downregulation of matrix metalloproteinases (MMP) inhibitors, which leads to activation of MMPs, thus promoting invasiveness of cancer cells. (PMID:18591254)
• The combination of assays presented here supports a role for miR-17-92 polycistron and miR-21 in the maintenance of the malignant transformation of hepatocytes (PMID:18688024)
• results suggest that overexpression of mature miR-21 is an independent negative prognostic factor for overall survival in NSCLC patients (PMID:18719201)
• findings suggest a potential regulatory pathway in which H. pylori infection upregulates expression of miR-21, which in turn downregulates RECK, and then leads to the development of gastric cancer (PMID:18794849)
• Mir-21 is a putative oncogenic microRNA in Head and Neck Squamous Cell Carcinoma (HNSCC). (PMID:18798260)
• miR-21 may serve as a molecular prognostic marker for breast cancer and disease progression. (PMID:18812439)
• miR-21 as an important oncogene that targets a network of p53, TGF-beta, and mitochondrial apoptosis tumor suppressor genes in glioblastoma cells. (PMID:18829576)
• Elevated miR-21 expression may facilitate breast cancer progression, and TGF-beta may up-regulate its expression (PMID:18932017)
• K15M may contribute to Kaposi’s sarcoma associated herpesvirus-mediated tumor metastasis and angiogenesis via regulation of miR-21 and miR-31, which we show here for the first time to be a specific regulator of cell migration. (PMID:18971265)
• Inhibition of miR-21 increases endogenous levels of PDCD4 in cell line T98G and over-expression miR-21 inhibits PDCD4-dependent apoptosis (PMID:19013014)
• Unsaturated fatty acids inhibit PTEN expression in hepatocytes by up-regulating microRNA-21 synthesis via an mTOR/NF-kappaB-dependent mechanism. (PMID:19072831)
• miR-21 is significantly upregulated in the majority of non-invasive intraductal papillary mucinous neoplasms. Expression correlates with histological features of progression. (PMID:19106647)
• miRNA-21 was hyperexpressed in all human astrocytic tumor samples (PMID:19159078)
• high expression of mir-21 indicates a more aggressive phenotype in breast cancer (PMID:19212625)
• results demonstrate that E(2) represses the expression of an oncogenic miRNA, miR-21, by activating estrogen receptor in MCF-7 cells. (PMID:19264808)
• MicroRNA-21 targets PDCD4 at the posttranscriptional level and regulates cell proliferation and invasion in esophageal squamous cell carcinoma. (PMID:19276261)
• overexpressed in human cholangiocarcinoma (PMID:19296468)
• These data suggested that miR-21 could promote apoptosis resistance, motility, and invasion in prostate cancer cells and these effects of miR-21 may be partly due to its regulation of PDCD4, TPM1, and MARCKS. (PMID:19302977)
• miR21-mediated inhibition of endogenous WNT1 and JAG1 expression was important for proper monocyte-derived dendritic cell differentiation (PMID:19398721)
• miR-21 acts as a positive, though indirect, regulator of FOXP3 expression in Treg (PMID:19408243)
• miR-21 is up-regulated via the MAPK (ERK1/2) pathway upon stimulation of HER2/neu signaling in breast cancer cells (PMID:19419954)
• Results show that an A-G mutation at 29-nt downstream of pre-miR-21 led to a conformational change of the secondary structure close to the stem reaching into the pre-miR-21 and a relative reduction of the mature miR-21 expression in vivo. (PMID:19430705)
• miR-21 expression is increased in pancreatic cancer cells and that miR-21 contributes to the cell proliferation, invasion, and chemoresistance of pancreatic cancer (PMID:19435867)
• Mir-21 expression in the sputum specimens was significantly higher in non-small cell lung cancer patients than cancer-free individuals (PMID:19446359)
• miR-21 was detectable in precancerous adenomas. The frequency and extent of miR-21 expression increased during the transition from precancerous colorectal adenoma to advanced carcinoma (PMID:19509156)
• miR-21 is an independent prognostic indicator for tongue squamous cell carcinomas (TSCC), and may play a role in TSCC development by inhibiting cancer cell apoptosis partly via TPM1 silencing. (PMID:19509158)
• Mir-21 was found to be overexpressed in laryngeal carcinoma tissues and expression of miR-21 may contribute to the malignant phenotype of laryngeal carcinoma by maintaining a low level of BTG2. (PMID:19546886)
• Differential expression of microRNA 181b and microRNA 21 in hyperplastic polyps and sessile serrated adenomas of the colon. (PMID:19547998)
• miR-21 represents a promising target for therapeutic manipulation to increase the efficacy of chemotherapeutic agents in treating glioblastoma. (PMID:19559015)

Cross-species orthologs

2 orthologs

Organism	Symbol	Gene ID
danio_rerio	dre-mir-21-2	ENSDARG00000080484
mus_musculus	Mir21a	ENSMUSG00000065455

Protein

Non-coding RNA — no protein product; not a drug target.

Function

No curated pathway, Gene-Ontology, or interaction data.

Disease & clinical

No curated disease, variant, or cancer-driver associations.

Drugs & pharmacology

No drug or pharmacology data — not an established drug target.