The Let-7 microRNA precursor was identified from a study of developmental timing in C. elegans, and was later shown to be part of a much larger class of non-coding RNAs termed microRNAs. miR-98 microRNA precursor from human is a let-7 family member. Let-7 miRNAs have now been predicted or experimentally confirmed in a wide range of species (MIPF0000002). miRNAs are initially transcribed in long transcripts called primary miRNAs (pri-miRNAs), which are processed in the nucleus by Drosha and Pasha to hairpin structures of about 70 nucleotide. These precursors (pre-miRNAs) are exported to the cytoplasm by exportin5, where they are subsequently processed by the enzyme Dicer to a ~22 nucleotide mature miRNA. The involvement of Dicer in miRNA processing demonstrates a relationship with the phenomenon of RNA interference.
The miR-103 microRNA precursor, is a short non-coding RNA gene involved in gene regulation. miR-103 and miR-107 have now been predicted or experimentally confirmed in human.
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-129 microRNA precursor is a small non-coding RNA molecule that regulates gene expression. This microRNA was first experimentally characterised in mouse and homologues have since been discovered in several other species, such as humans, rats and zebrafish. The mature sequence is excised by the Dicer enzyme from the 5' arm of the hairpin. It was elucidated by Calin et al. that miR-129-1 is located in a fragile site region of the human genome near a specific site, FRA7H in chromosome 7q32, which is a site commonly deleted in many cancers. miR-129-2 is located in 11p11.2.
mir-133 is a type of non-coding RNA called a microRNA that was first experimentally characterised in mice. Homologues have since been discovered in several other species including invertebrates such as the fruitfly Drosophila melanogaster. Each species often encodes multiple microRNAs with identical or similar mature sequence. For example, in the human genome there are three known miR-133 genes: miR-133a-1, miR-133a-2 and miR-133b found on chromosomes 18, 20 and 6 respectively. The mature sequence is excised from the 3' arm of the hairpin. miR-133 is expressed in muscle tissue and appears to repress the expression of non-muscle genes.
The miR-17 microRNA precursor family are a group of related small non-coding RNA genes called microRNAs that regulate gene expression. The microRNA precursor miR-17 family, includes miR-20a/b, miR-93, and miR-106a/b. With the exception of miR-93, these microRNAs are produced from several microRNA gene clusters, which apparently arose from a series of ancient evolutionary genetic duplication events, and also include members of the miR-19, and miR-25 families. These clusters are transcribed as long non-coding RNA transcripts that are processed to form ~70 nucleotide microRNA precursors, that are subsequently processed by the Dicer enzyme to give a ~22 nucleotide products. The mature microRNA products are thought to regulate expression levels of other genes through complementarity to the 3' UTR of specific target messenger RNA.
The miR-199 microRNA precursor is a short non-coding RNA gene involved in gene regulation. miR-199 genes have now been predicted or experimentally confirmed in mouse, human and a further 21 other species. microRNAs are transcribed as ~70 nucleotide precursors and subsequently processed by the Dicer enzyme to give a ~22 nucleotide product. The mature products are thought to have regulatory roles through complementarity to mRNA.
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.
miR-30 microRNA precursor is a small non-coding RNA that regulates gene expression. Animal microRNAs are transcribed as pri-miRNA of varying length which in turns are processed in the nucleus by Drosha into ~70 nucleotide stem-loop precursor called pre-miRNA and subsequently processed by the Dicer enzyme to give a mature ~22 nucleotide product. In this case the mature sequence comes from both the 3' (miR-30) and 5' (mir-97-6) arms of the precursor. The products are thought to have regulatory roles through complementarity to mRNA.
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.
Protein argonaute-2 is a protein that in humans is encoded by the EIF2C2 gene.
Polypyrimidine tract-binding protein 1 is a protein that in humans is encoded by the PTBP1 gene.
miR-96 microRNA precursor is a small non-coding RNA that regulates gene expression. microRNAs are transcribed as ~80 nucleotide precursors and subsequently processed by the Dicer enzyme to give a ~23 nucleotide products. 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.
In molecular biology, miR-137 is a short non-coding RNA molecule that functions to regulate the expression levels of other genes by various mechanisms. miR-137 is located on human chromosome 1p22 and has been implicated to act as a tumor suppressor in several cancer types including colorectal cancer, squamous cell carcinoma and melanoma via cell cycle control.
In molecular biology mir-451 microRNA is a short RNA molecule. MicroRNAs function to regulate the expression levels of other genes by several mechanisms.
In molecular biology mir-11 microRNA is a short RNA molecule. MicroRNAs function to regulate the expression levels of other genes by several mechanisms. There is an evidence to suggest that miR-11 plays a role in apoptosis.
In molecular biology mir-14 microRNA is a short RNA molecule. MicroRNAs function to regulate the expression levels of other genes by several mechanisms.
Epigenetic regulation of neurogenesis is the role that epigenetics plays in the regulation of neurogenesis.
