MicroBiology

MicroRNA is also abbreviated as miRNA. It is a single strand of RNA molecules that is upto 21-23 nucleotides in length. It is responsible for regulating the expression of genes. The genes transcribed from DNA encode the miRNA. The mature miRNA molecules are complimentary to some of the messenger RNA to some extent. They perform the important function of down regulating the expression of genes.

MiRNA is attached to a small piece of mRNA that is the master model to build the proteins in a non-coding pattern at one end of the molecules. These micro RNA’s are very small molecules that are coded in the genomes of animals and plants. They are highly conserved and play the role of regulating the gene expression by connecting the untranslated areas of particular mRNA’s.

Generally, the miRNA’s are transliterated as a part of the long RNA molecule. About 60% of this micro RNA’s are expressed independently; whereas the 15% of it in clusters and remaining 25% are expressed in introns. The mammalian genomes can encode about 200-500 miRNA’s that can together control the expression of 1/3^rd of all the genes.

The micro RNAs are produced and they function in the tissues, cells and organisms. They regulate multiple genes and are present in the higher Eukaryotes. Thus, the miRNA has adequate potential regulatory circuitry. They are the key regulators of the processes including cell death, cell proliferation, cell differentiation, fat metabolism, and apoptosis. The recent studies reveal that the expression of the miRNA is associated with the brain development, viral infection, colonic adenocarcinoma chronic lymphocytic leukemia and Burkitt’s lymphoma.

MiRNA and Cancer- it has been found that there are some miRNA’s that have a link to some type of caner. The patterns of gene activity distinguishing the kind of cancer can be detected by measuring the activity between the 217 genes that encode the miRNA. The signatures of miRNA make it possible to classify the types of cancer. This helps the doctor in determining the original type of tissue causing cancer and thus, the treatment course can be targeted based on the original type of tissue. The profiling of the micro RNA has enabled in verifying the patients having chronic leukemia with slow or aggressive forms of cancer.

MiRNA and Heart Disease- miRNA plays an important role in the functioning of the heart and its role during its development is quite significant. Studies show that the level of expression of a particular miRNA alters in diseased human hearts. It has distinct roles to play at the time of the development of heart, and pathological functions include regulating the key factors necessary for cardiogenesis, cardiac conductance and hypertrophic growth response.

The miRNA’s are significant for the development of the organisms and are expressed differentially in the tissues. They are involved in the processes of viral infection and are also associated with oncogenesis. The activity of these miRNA’s can be blocked experimentally using a Morpholino Oligo, locked nucleic acid or methyl RNA Oligo. The steps in its maturation process can also be blocked using steric blocking oligos.

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