1 / 9

MicroRNA

MicroRNA. INTRODUCTION. miRNAs are RNA genes which are transcribed from DNA, but are not translated into protein . A miRNA (micro-RNA) is a form of single-stranded RNA which is typically 20-25 nucleotide long . It is thought to regulate the expression of other genes.

perrin
Download Presentation

MicroRNA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. MicroRNA

  2. INTRODUCTION • miRNAs are RNA genes which are transcribedfrom DNA, but are nottranslatedintoprotein. • A miRNA (micro-RNA) is a form of single-stranded RNA which is typically 20-25 nucleotide long. • It is thought to regulate the expression of other genes. • The DNA sequencethatcodesforanmiRNA gene islongerthanthemiRNAitself. This DNA sequenceincludesthemiRNAsequence and anapproximate reverse complement

  3. FORMATION OF miRNA • When this DNA sequence istranscribed into a single-stranded RNA molecule, the miRNA sequence and its reverse-complement base pair to form a double stranded RNA hairpin loop; this forms a primary miRNA structure (pri-miRNA)

  4. In animals: the nuclear enzyme Drosha cleaves the base of the hairpin to form pre-miRNA. The pre-miRNA molecule is then actively transported out of the nucleus into the cytoplasm by Exportin 5, a carrier protein. The Dicer enzyme then cuts 20-25 nucleotides from the base of the hairpin to release the mature miRNA. • In plants: which lack Drosha homologues, pri- and pre-miRNA processing by Dicer probably takesplace in the nucleus, and mature miRNA duplexes are exported to the cytosol by Exportin 5.

  5. FUNCTION OF miRNA • Mature miRNA molecules are either fully or partially complementary to one or more messenger RNA (mRNA) molecules, and their main function is to down-regulate gene expression. • Animal miRNAs are usually complementary to a site in the 3' UTR • whereas plant miRNAs are usually complementary to coding regions of mRNAs. Perfect or near perfect base pairing with the target RNA promotes cleavage of the RNA • miRNAs function in association with a complement of proteins collectively termed the miRNP

  6. DETECTION OF miRNA • MicroRNA expression can be quantified by being profiled against a database describing thousands of known miRNAs using microarray technology • It was initially thought that miRNA genes were located in intergenic regions, however, later study showed that several miRNA genes were located within introns of either protein-coding or noncodinggenes while only a few were located in exons of noncoding RNAs or UTR of protein coding genes

  7. Thank You

More Related