What are micro RNAs?
Micro RNAs (miRNA) are small non-coding RNAs that are involved in regulating the translation of messenger RNA (mRNA). Over 1000 miRNAs have been identified which control approximately 60% of the protein coding genes1. The miRNAs are on average 23 nucleotides long, with nucleotides 2-7 acting as the seed region. The seed region is needed for specific mRNA interactions and mutations occur in this region it can disrupt the miRNA, mRNA Watson-Crick base pairing2.
mRNA is stabilized in the cytoplasm by adding a 5’ cap and a 3’ poly adenine tail, which prevents degradation by ribonucleases. The binding of miRNA can cause 3 events to occur; deadenylation, decapping, and 5’ to 3’ degradation1. Often in the 3’ untranslated region (UTR) there are AU rich elements (AREs) when the miRNA along with Argonaute 1, Argonaute 2 and Dicer1 is bound it allows rapid decay of the mRNA
1.2. miRNA biogenesis
miRNAs can be transcribed from their own genes; often there are clusters of these miRNA genes for example, C19MC, which is the largest human cluster3. Another place where miRNAs are coded for is within introns of other genes. The miRNAs are transcribed using either RNA polymerase II or III4,5, this is dependent on the specific promoter or terminator sequences for each gene. The new transcript is called the primary miRNA (pri-miRNA) and must undergo processing before it is able to regulate mRNA.
While in the nucleus the pri-miRNA undergoes the first cleavage, which is catalysed by Drosha, figure 1. Drosha is part of the RNase III family of enzymes and cleaves the transcript 11 base pairs from the double stranded/single stranded RNA junction3. For the cleavage to be accurate a molecular ruler in the form of Pasha (p...
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...t leads to a truncated TRBP. Cell lines that exhibited this mutated TRBP also had extremely low levels of Dicer. When wild type TRBP was restored to the cancer cell lines, Dicer expression increased to WT levels16. A study into nearly 300 primary human colorectal (sporadic or familial) or gastric (sporadic) cancers, from these 25.4% presented the mutant TRBP, and it was highest in familial colorectal cancers at 43.3%16.
1.4. Angiogenesis
The process of angiogenesis is the development of blood vessels. It is vital for all higher organisms, as oxygen is not able to diffuse throughout the body, but must be carried to cells far from the lungs.
One of the main system that controls angiogenesis and the maintenance of the blood vessels is angiopoietin-TIE17. TIE1 and TIE2 are tyrosine kinase receptors that have extracellular domains similar to that of EGF and Ig18.
Regulation- Blood vessels help maintain a stable body temperature by controlling the blood flow to the surface of the skin (Terfera, David, and Jegtvi)
The Structure and Functions of the Arteries Arteries are blood vessels that convey blood from the heart to the tissues of the body. The arteries expand and then constrict with each beat of the heart, a rhythmic movement that may be felt as the pulse. Arteries are usually named from the part of the body that they are found, for example; brachial artery found in the arms, metacarpal artery found in the wrist; or from the organ which they supply as the hepatic artery supplies the liver, pulmonary artery brings deoxygenated blood the lungs. The facial artery is the branch of the external carotid artery that passes up over the lower jaw and supplies the superficial portion of the face; the haemorrhoidal arteries are three vessels that supply the lower end of the rectum; the intercostal arteries are the arteries that supply the space between the ribs; the lingual artery is the branch of the external carotid artery that supplies the tongue. The structure of the artery enables it to perform its function more efficiently.
What has to happen for a gene to be transcribed? The enzyme RNA polymerase, which makes a new RNA molecule from a DNA template, must attach to the DNA of the gene. It attaches at a spot called the promoter.
...ds a supply of its own blood to function properly. These arteries, called the coronary arteries, are responsible for this. The blockage of these arteries prevents oxygen from reach the heart tissue and leads to what is known as a heart attack.
If a certain disease was caused by abnormally expression of PGE4B, we could, theoretically, inject the miR-23b and cure the disease. On the other hand, ifsomeone has a diseases caused by misregulation of PGE4B’s expression because of the unusual expression of miR-23b. In that case, we can change the expression of miR-23b itself to restore the imbalance in gene expression and cure the disease. Additionally, qPCR can only tell us that the gene is a target, but it does not give us information about whether the gene is directly or secondarily regulated by the miRNA [15]. This is another question that needs to be
O’Leary, T. 1999 Molecular diagnosis of hereditary nonpolyposis colorectal cancer. JAMA: Journal of the American Medical Association. 282 (3): 281+.
The circulatory system and respiratory system share a highly important relationship that is crucial to maintaining the life of an organism. In order for bodily processes to be performed, energy to be created, and homeostasis to be maintained, the exchange of oxygen from the external environment to the intracellular environment is performed by the relationship of these two systems. Starting at the heart, deoxygenated/carbon-dioxide (CO2)-rich blood is moved in through the superior and inferior vena cava into the right atrium, then into the right ventricle when the heart is relaxed. As the heart contracts, the deoxygenated blood is pumped through the pulmonary arteries to capillaries in the lungs. As the organism breathes and intakes oxygenated air, oxygen is exchanged with CO2 in the blood at the capillaries. As the organism breathes out, it expels the CO2 into the external environment. For the blood in the capillaries, it is then moved into pulmonary veins and make
micro RNAs (miRNAs) are small non-coding RNas with approximately 20 nucleotides in length. They control gene expression during post-transcription by binding to 3’ or 5’ untranslated regions of the target mRNAs, which prevent translation, or mRNA degradation.
added to the 3¹ end. As the two ends are placed the mRNA becomes pre-mRNA.
The American Cancer Society publishes current advances made in cancer research on their website. Many of the exciting discoveries about how best to treat the disease focus on the genetic aspects associated with certain types of cancer. In addition, treatments aimed at genetic solutions to cancer may be more effective and may cause fewer adverse side effects than traditional cancer treatments (American Can...
RNA can control how much protein is made but also when it is made. Due to the macromolecular structure of RNA, it has been discovered to have the ability to
Our blood is able to connect all our organs together to create one organism and is able to transport the most vital and important molecules through these blood streams. Hence, blood cells are needed for immune system function and metabolic functions.
The three main types of blood vessels; artery begin with the aorta, the large artery leaving the heart, they carry oxygen rich blood away from the heart to all of the body tissues. They branch several times becoming smaller and smaller as they carry blood further from the heart. Capillaries are small, thin blood vessels that connect the arteries and veins. Veins these are blood vessels that take oxygen poor in blood back to the heart. The veins become large and large as they get closer to the heart. The superior vena cava is the large vein that brings blood from the head and arms to the heart and the inferior vena cava brings blood from the abdomen and legs into the heart. James (1999) stated that this vast system of blood vessels; arteries, veins and capillaries is over 60000 miles long. That’s long enough to go around the world more than twice. Blood flows continuously through your body’s blood
UTRs are an important component of an mRNA sequence because they are involved in regulation and stability of translation.