mir-10 | |
---|---|
Identifiers | |
Symbol | miR-10 |
Alt. Symbols | miR-51, miR-57, miR-99, miR-100 |
Rfam | RF00104 |
miRBase family | MIPF0000033 |
HGNC | 31497 |
OMIM | 610173 |
Other data | |
RNA type | microRNA |
Domain(s) | Eukaryota; Metazoa |
PDB structures | PDBe |
The mir-10 microRNA precursor is a short non-coding RNA gene involved in gene regulation. It is part of an RNA gene family which contains mir-10, mir-51, mir-57, mir-99 and mir-100. mir-10, mir-99 and mir-100 have now been predicted or experimentally confirmed in a wide range of species. [1] [2] (MIPF0000033, MIPF0000025) miR-51 and miR-57 have currently only been identified in the nematode Caenorhabditis elegans (MIPF0000268, MIPF0000271).
MicroRNAs are transcribed as ~70 nucleotide precursors and subsequently processed by the Dicer enzyme to give a ~22 nucleotide product. In this case the mature sequence comes from the 5' arm of the precursor. The mature products are thought to have regulatory roles through complementarity to mRNA.
The presence of miR-10 has been detected in a diverse range of bilaterian animals. It is one of the most widely distributed microRNAs in animals, it has been identified in numerous species including human, dog, cat, horse, cow, guinea pig, mouse, rat, common marmoset (Callithrix jacchus), common chimpanzee (Pan troglodytes), rhesus monkey (Macaca mulatta), Sumatran orangutan (Pongo abelii), northern greater galago (Otolemur garnettii), gray short-tailed opossum (Monodelphis domestica), northern treeshrew (Tupaia belangeri), European rabbit (Oryctolagus cuniculus), African bush elephant (Loxodonta africana), nine-banded armadillo (Dasypus novemcinctus), European hedgehog (Erinaceus europaeus), lesser hedgehog tenrec (Echinops telfairi), zebra finch (Taeniopygia guttata), chicken, platypus (Ornithorhynchus anatinus), Western clawed frog (Xenopus tropicalis), Carolina anole (Anolis carolinensis), zebrafish (Danio rerio), Japanese pufferfish (Fugu rubripes), green spotted pufferfish (Tetraodon nigroviridis), Japanese killifish (Oryzias latipes), three-spined stickleback (Gasterosteus aculeatus), Florida lancelet (Branchiostoma floridae), California purple sea urchin (Strongylocentrotus purpuratus), 12 different species of fruit fly ( Drosophila ), Western honey bee (Apis mellifera), mosquito ( Anopheles gambiae ), red flour beetle (Tribolium castaneum), the nematode Caenorhabditis elegans , owl limpet (Lottia gigantea), starlet sea anemone (Nematostella vectensis) and the blood fluke Schistosoma japonicum . [3] [4] [5] [6] [7] [8] In some of these species the presence of miR-10 has been shown experimentally, in others the genes encoding miR-10 have been predicted computationally.
The mir-10 genes are found within the Hox gene clusters. In mammals there are four Hox gene clusters, these contain five genes encoding miRNAs (mir-10a, mir-10b, mir-196a-1, mir-196a-2 and mir-196b). The mir-10a gene is located upstream of Hoxb4 and the mir-10b gene is located upstream of Hoxd4 . [9] Zebrafish have seven Hox gene clusters, genes encoding miR-10 (mir-10a, mir-10b-1, mir-10b-2 and mir-10c) are found in the Hox Ba, Bb, Ca and Da clusters. A fourth miR-10 gene (mir-10d) is found elsewhere in the genome, at a location homologous to the pufferfish HoxDd cluster. [10]
A miRNA can be derived from each arm of the pre-miRNA hairpin. Historically, the least common of these two miRNA products was denoted by the addition of * to the miRNA name, however the modern convention is to denote mature miRNA products as 5p or 3p. [11] Both mir-10 and mir-10* have been detected in Drosophila. There are many potential targets for miR-10* in Drosophila, including several Hox genes, indicating that miR-10* may also be functional. [12] [13] In Drosophila most mature miR-10 sequences are produced from the 3' arm of the precursor while in the beetle Tribolium castaneum most production comes from the 5' arm. [14] These changes of arm preference during evolution are termed arm switching events, and they are relatively frequent during the evolution of microRNAs. [14] [15]
In adult animals, expression of miR-10 is limited to specific organs. The highest levels of miR-10a and miR-10b have been found in the kidneys of mice. Lower levels of miR-10a are seen in small intestine, lung and spleen, and lower levels of miR-10b are seen in skeletal muscle. Expression of miR-10b has also been detected in the ovaries. [7] [8] [16] Adult zebrafish express miR-10a in heart, testis and ovary, and miR-10b in muscle and liver. [17]
In developing embryos, miR-10 is detected at specific stages. Zebrafish embryos show miR-10a expression from 48 to 120 hours post-fertilisation, and miR-10b expression from 12 to 120 hours post-fertilisation. [17] In Drosophila expression of miR-10-3p is highest in 12- to 24-hour-old embryos and in 1st and 3rd instar larvae. Levels of miR-10-5p are highest in 12- to 24-hour-old embryos and much lower in larvae. [12]
In stage 5 Drosophila embryos (130–180 minutes post-fertilisation), miR-10 is distributed throughout 50-80% of the length of the egg. Later in development miRNA-10 becomes localised into bands, and levels decrease by stage 7 (195–200 minutes post-fertilisation). miR10 reappears by stage 11 (320–440 minutes post-fertilisation), where it is found in the ventral nerve cord, posterior midgut and hindgut. At stage 14 (620–680 hours post-fertilisation), miRNA-10 is localised to the posterior midgut and the anal pad. [18] In Drosophila larvae, miR-10-3p is found in the imaginal discs (groups of cells which are destined to become adult structures upon metamorphosis). [12] Expression of miR-10ba in mouse embryos shows a similar pattern to that of the Hoxb4 gene. Highest levels are found in the posterior trunk of the embryo, surrounding the hindlimb buds. Similarly, expression is restricted to the posterior trunk of chicken embryos. [6] In Zebrafish embryos expression of miR-10 is also restricted to the posterior trunk, later in development it is further restricted to the spinal cord. [17]
A number of Hox genes have been shown to be regulated by miR-10. These genes encode transcription factors which are important in embryonic development. In zebrafish embryos, miR-10 binds to sites in the three prime untranslated region (3'UTR) of the HoxB1a and HoxB3a genes, which are important in anterior-posterior patterning during embryonic development. Binding of miR-10 leads to the repression of these genes. It also acts synergistically with HoxB4 to repress these genes. The mir-10 gene is located near to the HoxB1a and HoxB3a genes within the zebrafish genome, Hox-1 and Hox-3 paralogues located on different Hox clusters are not targets of miR-10. [19] Human HOXD10 gene has also been shown experimentally to be repressed by miR-10a and miR-10b. [9] [20] [21]
It has also been experimentally verified that miR-10a downregulates the human HOXA1 and HOXA3 genes. [21] [22] Control of the Hox genes by miR-10 suggests that this microRNA may play an important role in development. [9]
In addition to the Hox genes, miR-10a represses the transcription factor USF2 and the Ran and Pbp1 genes. [23] [24] The cell-surface proteoglycan Syndecan-1 is a target of miR-10b. [25] [26]
miR-10a binds to the five prime untranslated region (5'UTR) of mRNAs encoding ribosomal proteins, and increases their translation. It binds immediately downstream of the 5' oligopyrimidine tract (5'TOP) motif, a region important in the regulation of ribosomal protein synthesis. [23]
Recently there has been much interest in abnormal levels of expression of microRNAs in cancers. Upregulation of miR-10 has been found in a number of cancers. Increased levels of miR-10a have been found in glioblastoma, anaplastic astrocytomas, primary hepatocellular carcinomas and colon cancer. Increased levels of miR-10b have been found in glioblastoma, anaplastic astrocytomas, pancreatic cancer, and metastatic breast cancer. [9] [20] Although high expression of miR-10b is found in metastatic breast cancers, it does not appear to be present at high levels in early breast cancers. [20] [27] The expression of miR-10b is correlated with overall survival in 1262 breast cancer patients. [28]
Downregulation of miR-10a has been found in chronic myeloid leukemia. USF2, a target gene of miR-10a, has been found to be overexpressed in these leukemias. [24] Downregulation of miR-10a has also been found in acute myeloid leukemia, the most common acute leukemia affecting adults. [29] Conversely, miR-10a and miR-10b have found to be upregulated in acute myeloid leukemia with NPM1 mutations; these account for approximately a third of adult acute myeloid leukemia cases and contain mutations in the NPM1 gene which result in the relocation of NPM1 from the nucleus to the cytoplasm. [30] Upregulation of miR-10b has also been found in B-cell chronic lymphocytic leukemia, the most common type of leukemia. [31]
Genomic copy number abnormalities involving microRNA genes (both increases and decreases in copy number) have been found in cancers. A gain in copy number of the mir-10a gene has been found in melanoma and breast cancer. [32]
Upstream of the mir-10b gene is a promoter region containing a binding site for the Twist transcription factor (Twist). Binding of Twist to this promoter region induces miR-10b expression, leading to a reduced translation of the tumour suppressor HOXD10. This results in upregulation of RhoA/RhoC, Rho kinase activation and tumour cell invasion. [20] [33]
Boston, Massachusetts-based Transcode Therapeutics is developing drugs to target Mir-10b, which the company regards as "a master regulator of metastatic disease". [34] Preclinical trials in a murine model of metastatic breast cancer found that one of their drugs candidates, MN-anti-miR10b (now known as TTX-MC138), combined with low-dose doxorubicin, resulted in a complete elimination of distant metastases in 65% of the rodents and a significant decrease in mortality. [35] A first-in-human phase 0 study of TTX-MC138 began in 2023. The company believes the drug, and others with similar mechanisms, could dramatically increase survival rates for people with metastatic tumors. [36]
The miR-9 microRNA, is a short non-coding RNA gene involved in gene regulation. The mature ~21nt miRNAs are processed from hairpin precursor sequences by the Dicer enzyme. The dominant mature miRNA sequence is processed from the 5' arm of the mir-9 precursor, and from the 3' arm of the mir-79 precursor. The mature products are thought to have regulatory roles through complementarity to mRNA. In vertebrates, miR-9 is highly expressed in the brain, and is suggested to regulate neuronal differentiation. A number of specific targets of miR-9 have been proposed, including the transcription factor REST and its partner CoREST.
The miR-15 microRNA precursor family is made up of small non-coding RNA genes that regulate gene expression. The family includes the related mir-15a and mir-15b sequences, as well as miR-16-1, miR-16-2, miR-195 and miR-497. These six highly conserved miRNAs are clustered on three separate chromosomes. In humans miR-15a and miR-16 are clustered within 0.5 kilobases at chromosome position 13q14. This region has been found to be the most commonly affected in chronic lymphocytic leukaemia (CLL), with deletions of the entire region in more than half of cases. Both miR-15a and miR-16 are thus frequently deleted or down-regulated in CLL samples with 13q14 deletions; occurring in more than two thirds of CLL cases. The expression of miR-15a is associated with survival in triple negative breast cancer.
In molecular biology miR-181 microRNA precursor is a small non-coding RNA molecule. MicroRNAs (miRNAs) are transcribed as ~70 nucleotide precursors and subsequently processed by the RNase-III type enzyme Dicer to give a ~22 nucleotide mature product. In this case the mature sequence comes from the 5' arm of the precursor. They target and modulate protein expression by inhibiting translation and / or inducing degradation of target messenger RNAs. This new class of genes has recently been shown to play a central role in malignant transformation. miRNA are downregulated in many tumors and thus appear to function as tumor suppressor genes. The mature products miR-181a, miR-181b, miR-181c or miR-181d are thought to have regulatory roles at posttranscriptional level, through complementarity to target mRNAs. miR-181 has been predicted or experimentally confirmed in a wide number of vertebrate species such as rat, zebrafish, and pufferfish.
miR-196 is a non-coding RNA called a microRNA that has been shown to be expressed in humans and mice. miR-196 appears to be a vertebrate specific microRNA and has now been predicted or experimentally confirmed in a wide range of vertebrate species. In many species the miRNA appears to be expressed from intergenic regions in HOX gene clusters. The hairpin precursors are predicted based on base pairing and cross-species conservation—their extents are not known. In this case the mature sequence is excised from the 5' arm of the hairpin.
There are 89 known sequences today in the microRNA 19 (miR-19) family but it will change quickly. They are found in a large number of vertebrate species. The miR-19 microRNA precursor is a small non-coding RNA molecule that regulates gene expression. Within the human and mouse genome there are three copies of this microRNA that are processed from multiple predicted precursor hairpins:
The miR-1 microRNA precursor is a small micro RNA that regulates its target protein's expression in the cell. microRNAs are transcribed as ~70 nucleotide precursors and subsequently processed by the Dicer enzyme to give products at ~22 nucleotides. In this case the mature sequence comes from the 3' arm of the precursor. The mature products are thought to have regulatory roles through complementarity to mRNA. In humans there are two distinct microRNAs that share an identical mature sequence, and these are called miR-1-1 and miR-1-2.
The miR-29 microRNA precursor, or pre-miRNA, is a small RNA molecule in the shape of a stem-loop or hairpin. Each arm of the hairpin can be processed into one member of a closely related family of short non-coding RNAs that are involved in regulating gene expression. The processed, or "mature" products of the precursor molecule are known as microRNA (miRNA), and have been predicted or confirmed in a wide range of species.
The mir-2 microRNA family includes the microRNA genes mir-2 and mir-13. Mir-2 is widespread in invertebrates, and it is the largest family of microRNAs in the model species Drosophila melanogaster. MicroRNAs from this family are produced from the 3' arm of the precursor hairpin. Leaman et al. showed that the miR-2 family regulates cell survival by translational repression of proapoptotic factors. Based on computational prediction of targets, a role in neural development and maintenance has been suggested.
The miR-34 microRNA precursor family are non-coding RNA molecules that, in mammals, give rise to three major mature miRNAs. The miR-34 family members were discovered computationally and later verified experimentally. The precursor miRNA stem-loop is processed in the cytoplasm of the cell, with the predominant miR-34 mature sequence excised from the 5' arm of the hairpin.
The mir-6 microRNA precursor is a precursor microRNA specific to Drosophila species. In Drosophila melanogaster there are three mir-6 paralogs called dme-mir-6-1, dme-mir-6-2, dme-mir-6-3, which are clustered together in the genome. The extents of these hairpin precursors are estimated based on hairpin prediction. Each precursor is generated following the cleavage of a longer primary transcript in the nucleus, and is exported in the cytoplasm. In the cytoplasm, precursors are further processed by the enzyme Dicer, generating ~22 nucleotide products from each arm of the hairpin. The products generated from the 3' arm of each mir-6 precursor have identical sequences. Both 5' and 3' mature products are experimentally validated. Experimental data suggests that the mature products of mir-6 hairpins are expressed in the early embryo of Drosophila and target apoptotic genes such as hid, grim and rpr.
This family represents the microRNA (miRNA) precursor mir-7. This miRNA has been predicted or experimentally confirmed in a wide range of species. miRNAs are transcribed as ~70 nucleotide precursors and subsequently processed by the Dicer enzyme to give a ~22 nucleotide product. In this case the mature sequence comes from the 5' arm of the precursor. The extents of the hairpin precursors are not generally known and are estimated based on hairpin prediction. The involvement of Dicer in miRNA processing suggests a relationship with the phenomenon of RNA interference.
The miR-92 microRNAs are short single stranded non-protein coding RNA fragments initially discovered incorporated into an RNP complex with a proposed role of processing RNA molecules and further RNP assembly. Mir-92 has been mapped to the human genome as part of a larger cluster at chromosome 13q31.3, where it is 22 nucleotides in length but exists in the genome as part of a longer precursor sequence. There is an exact replica of the mir-92 precursor on the X chromosome. MicroRNAs are endogenous triggers of the RNAi pathway which involves several ribonucleic proteins (RNPs) dedicated to repressing mRNA molecules via translation inhibition and/or induction of mRNA cleavage. miRNAs are themselves matured from their long RNA precursors by ribonucleic proteins as part of a 2 step biogenesis mechanism involving RNA polymerase 2.
Homeobox D10, also known as HOXD10, is a protein which in humans is encoded by the HOXD10 gene.
In molecular biology mir-126 is a short non-coding RNA molecule. MicroRNAs function to regulate the expression levels of other genes by several pre- and post-transcription mechanisms.
In molecular biology, mir-145 microRNA is a short RNA molecule that in humans is encoded by the MIR145 gene. MicroRNAs function to regulate the expression levels of other genes by several mechanisms.
In molecular biology, miR-184 microRNA is a short non-coding RNA molecule. MicroRNAs (miRNAs) function as posttranscriptional regulators of expression levels of other genes by several mechanisms. Several targets for miR-184 have been described, including that of mediators of neurological development, apoptosis and it has been suggested that miR-184 plays an essential role in development.
In molecular biology MicroRNA-223 (miR-223) is a short RNA molecule. MicroRNAs function to regulate the expression levels of other genes by several mechanisms. miR-223 is a hematopoietic specific microRNA with crucial functions in myeloid lineage development. It plays an essential role in promoting granulocytic differentiation while also being associated with the suppression of erythrocytic differentiation. miR-223 is commonly repressed in hepatocellular carcinoma and leukemia. Higher expression levels of miRNA-223 are associated with extranodal marginal-zone lymphoma of mucosa-associated lymphoid tissue of the stomach and recurrent ovarian cancer. In some cancers the microRNA-223 down-regulation is correlated with higher tumor burden, disease aggressiveness, and poor prognostic factors. MicroRNA-223 is also associated with rheumatoid arthritis, sepsis, type 2 diabetes, and hepatic ischemia.
miR-31 has been characterised as a tumour suppressor miRNA, with its levels varying in breast cancer cells according to the metastatic state of the tumour. From its typical abundance in healthy tissue is a moderate decrease in non-metastatic breast cancer cell lines, and levels are almost completely absent in mouse and human metastatic breast cancer cell lines. Mir-31-5p has also been observed upregulated in Zinc Deficient rats compared to normal in ESCC and in other types of cancers when using this animal model. There has also been observed a strong encapsulation of tumour cells expressing miR-31, as well as a reduced cell survival rate. miR-31's antimetastatic effects therefore make it a potential therapeutic target for breast cancer. However, these two papers were formally retracted by the authors in 2015.
miR-191 is a family of microRNA precursors found in mammals, including humans. The ~22 nucleotide mature miRNA sequence is excised from the precursor hairpin by the enzyme Dicer. This sequence then associates with RISC which effects RNA interference.
mir-615 microRNA is a short non-coding RNA molecule belonging both to the family of microRNAs and to that of small interfering RNAs (siRNAs). MicroRNAs function to regulate the expression levels of other genes by several mechanisms, whilst siRNAs are involved primarily with the RNA interference (RNAi) pathway. siRNAs have been linked through some members to the regulation of cancer cell growth, specifically in prostate adenocarcinoma.