MIRLET7B

Summary

MIRLET7B (microRNA let-7b, HGNC:31479) is a microRNA gene on chromosome 22q13.31.

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 406884 — 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:31479
Approved symbol	MIRLET7B
Name	microRNA let-7b
Location	22q13.31
Locus type	RNA, micro
Status	Approved
Aliases	hsa-let-7b
Ensembl gene	ENSG00000284520
Ensembl biotype	miRNA
OMIM	611249
Entrez	406884
RNAcentral	URS000075A6A4 — miRNA, 83 nt, 1 organism(s)

Gene structure

Transcript identifiers

Ensembl transcripts: 1 — 1 miRNA

ENST00000385140

RefSeq mRNA: 0 — MANE Select: None

Canonical transcript exons

ENST00000385140 — 1 exons

Exon	Start	End
ENSE00001500146	46113686	46113768

Expression profiles

Bgee: expression breadth broad, 56 present calls, max score 96.55.

Top tissues by expression

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

Tissue	Anatomy ID	Expression score	Quality
epididymis	UBERON:0001301	96.55	gold quality
ovary	UBERON:0000992	96.15	gold quality
islet of Langerhans	UBERON:0000006	90.15	gold quality
renal glomerulus	UBERON:0000074	83.71	gold quality
placenta	UBERON:0001987	69.06	gold quality
gastrocnemius	UBERON:0001388	68.33	gold quality
Ammon’s horn	UBERON:0001954	68.30	gold quality
right hemisphere of cerebellum	UBERON:0014890	67.51	gold quality
blood	UBERON:0000178	67.15	gold quality
muscle layer of sigmoid colon	UBERON:0035805	66.97	gold quality
urinary bladder	UBERON:0001255	65.93	gold quality
upper lobe of left lung	UBERON:0008952	65.44	gold quality
right lobe of liver	UBERON:0001114	64.54	gold quality
esophagus mucosa	UBERON:0002469	64.16	gold quality
lower esophagus muscularis layer	UBERON:0035833	63.73	gold quality
prostate gland	UBERON:0002367	63.62	gold quality
esophagus	UBERON:0001043	62.96	gold quality
left lobe of thyroid gland	UBERON:0001120	62.96	gold quality
liver	UBERON:0002107	62.65	gold quality
body of stomach	UBERON:0001161	61.76	gold quality
caudate nucleus	UBERON:0001873	60.95	gold quality
tibial artery	UBERON:0007610	60.75	gold quality
dorsolateral prefrontal cortex	UBERON:0009834	59.47	gold quality
frontal lobe	UBERON:0016525	58.78	gold quality
right frontal lobe	UBERON:0002810	58.77	gold quality
putamen	UBERON:0001874	58.71	gold quality
anterior cingulate cortex	UBERON:0009835	58.37	gold quality
thyroid gland	UBERON:0002046	57.95	gold quality
ascending aorta	UBERON:0001496	57.75	gold quality
nucleus accumbens	UBERON:0001882	57.31	gold 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): HMGA2, NFKB

Literature-anchored findings (GeneRIF, showing 40)

• Results suggest that miRNAs -26a, -34a, -145, and let-7b may modulate expression of IFN-beta, thereby influencing innate immunity from the earliest responses to viral infection. (PMID:20130213)
• let-7a and let-7b expression decreases significantly following exposure to agents that induce stress including ionizing radiation and this decrease in expression is dependent on p53 and ATM. (PMID:22022355)
• let-7b expression was shown to be associated with luminal breast tumours and to have an independent significant positive prognostic value in this group. (PMID:22294324)
• A local let-7b microRNA increase may represent a risk factor in the formation of age-related cataracts. (PMID:22334139)
• Mutational analysis identified let-7b binding sites at the coding sequences of NS5B and 5’-UTR of HCV genome that were conserved among various HCV genotypes. (PMID:22391672)
• extracellular let-7 activates the RNA-sensing Toll-like receptor (TLR) 7 and induces neurodegeneration through neuronal TLR7 (PMID:22610069)
• Loss of Let-7b is associated with cancer. (PMID:22761738)
• Data indicate that microRNAs let-7b, let-7g and miR-18b expressed in higher levels associated with tumours. (PMID:22821209)
• Downregulation of let-7b with an MLL rearrangement via DNA hypermethylation of its regulatory region is associated with acute lymphoblastic leukemia. (PMID:22918121)
• let-7b and miR-126 are down-regulated in tumor tissue and correlate with microvessel density and survival outcomes in non–small–cell lung cancer. (PMID:23029111)
• circulating let-7b was lower in acute myocardial infarction patients than in controls at 4, 8, and 12 hours post-AMI. plasma concentration of let-7b could be a potential indicator for AMI. (PMID:23236408)
• Respiratory syncytial virus upregulates human let-7 and mir-30b microRNAs by using mechanisms involving beta interferon and NF-kappaB. (PMID:23249809)
• Let-7b targets at TLR4 mRNA, and regulates the activation of NF-kappaB and the expression of the downstream genes related to the inflammation and immune responses in H.pylori infection. (PMID:23437218)
• High let-7b expression is associated with ERBB2 overexpressing breast cancer. (PMID:23601657)
• HMGA1, a non-histone protein, is a target of let-7b in prostate cancer. (PMID:23798998)
• Elevated expression of let-7b is associated with high-grade serous ovarian carcinoma. (PMID:23825028)
• Circulating let-7b is lower in ischemic stroke patients with large-vessel atherosclerosis compared to controls. (PMID:24237608)
• let-7b might act as a cancer suppressor gene in BC development and progression by inhibiting the expression of BSG (PMID:24264599)
• Results suggest that the cancer-associated rs61764370 variant exerts a biological effect not through transcriptional modulation of KRAS but rather by tuning the expression of the microRNA let-7. (PMID:24282149)
• Decreased expression of let-7b is associated with oral squamous cell carcinoma. (PMID:24810113)
• Reduced let-7b might be involved in the pathogenesis of chronic thromboembolic pulmonary hypertension by affecting ET-1 and TGBR1 expression and function of arterial endothelial and smooth muscle cells. (PMID:24978044)
• The serum levels of MAGE-A and BORIS mRNA, as well as let-7b were significantly higher in patients. (PMID:24983365)
• Systemic nanodelivery of miR-34 and let-7 suppressed tumor growth leading to survival advantage. (PMID:25174400)
• the KDM2B/let-7b/EZH2 axis is involved in epigenetic regulation in MDS, with direct effects on di- and tri-methylation of H3K27. (PMID:25225797)
• Results show that LOX-1 is a target of let- 7a and let-7b, and they inhibit the expression of LOX-1 by targeting its 3’-UTR. (PMID:25247304)
• The expression of let-7b-5p was remarkably reduced in multiple myeloma tissues and cell lines, and the mRNA and protein levels of IGF1R in the RPMI-8226 cell line were down-regulated by let-7b-5p. (PMID:25274331)
• let-7b/g inhibited AKT2 expression by directly binding to its 3’UTR, reduced p-AKT (S473) activation and suppressed expression of the downstream effector pS6. (PMID:25288334)
• Study demonstrated that lncRNA-HOST2, which acts as a miRNA sponge, sequesters let-7b to maintain the expression of oncogenes and further maintains epithelial ovarian cancer biological functions. (PMID:25292198)
• let-7b increased 5-FU sensitivity by repressing Bcl-xl expression in HCC cells. (PMID:25333670)
• let-7b may directly target Cthrc1 and function as a tumor suppressor gene in gastric cancer. (PMID:25510669)
• Results indicate that let-7b overexpression can in turn downregulate cyclin D1 expression and enhance the radiosensitivity of uveal melanoma through cell cycle arrest. (PMID:25588203)
• Data indicate that knockdown of let-7b or let-7e could recover the growth rate and the invasion of cofilin-1 over-expressing cells. (PMID:25597880)
• Overexpression of let-7b in gastric cancer can inhibit invasion and migration of gastric cancer cells through directly targeting the tumor metastasis-associated gene ING1. (PMID:25613480)
• let-7b decreases drug resistance in gastric cancer cells by downregulating c-Myc. Cancer stem cell differentiation involves double-negative autoregulatory loops (Lin28/let-7 and Myc/let-7) and a double-positive autoregulatory loop (Lin28/Lin28B/Myc). (PMID:25633261)
• The above-mentioned data suggest that let-7b/i inhibit the invasive ability of glioma cells by directly downregulating IKBKE and indirectly upregulating E-cadherin. (PMID:25656572)
• the loss of let-7b in aggressive tumors may drive tumorigenesis by up-regulation of Aurora B and other targets of the miRNA, which further supports the role of let-7b in tumor suppression. (PMID:25682900)
• Upregulation of let-7b is associated with IgA nephropathy. (PMID:25744272)
• The combination of serum let-7b, 7d, and 7f levels during the proliferative phase may serve as a diagnostic marker for endometriosis. (PMID:25772772)
• Enterovirus 71 regulated the host SHSY5Y cell cycle and cell proliferation via stimulating endogenous miRNA let7b and directly targeting CCND1. (PMID:25779425)
• Specifically, significant down-regulation of the let-7p-5p, miR-98-5p and of miR-183-5p in the study groups (tumor alone and tumor and schizophrenia) was observed (p<0.05). (PMID:25856466)

Cross-species orthologs

0 orthologs

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.