Mirna Essay

MicroRNAs (miRNA) are small noncoding RNA, usually 17-25 nucleotides long that are able to bind complementary sequences of target messenger RNA (mRNA) and to induce both their degradation and translational repression (Fortunato, et al 2014). They are one of the most significant classes of non-coding RNA molecules (eg. small interfering RNA (siRNA) and ribozymes) that act within the cell. MiRNAs are also evolutionary conserved in different species from plants to humans and are encoded by their respective genes (Bader, 2012).

MiR-21 has been found to be over expressed in 20 pancreatic carcinoma tissues and cell lines compared to normal tissue or cell lines. (15)

In an in vitro model of cerebral ischemia, increase of miR-497 expression following oxygen-glucose deprivation, correlated with increased cell death and down regulation of its anti-apoptotic proteins, Bcl2 and Bclw [17]. Temporal regulation of miRNA expression has been shown in the brain of rat models subjected to middle cerebral artery occlusion (MCAo) [20]. An up regulation of the anti-apoptotic miR-21 has been shown to protect neurons from death in cerebral ischemic model. The temporal and biphasic regulation of these miRNAs have been proposed to play a crucial role either in the acute injury phase or the late recovery phase [16]. In addition, biphasic expression of miRNAs has also been demonstrated in the same animal models. Cerebral ischemia

gp41 (envelope antigen), are highly immunogenic, the antibody responses vary according to the virus load and the immune competence of the host. The antigenicity of these various components provides a means for detection of antibody, the basis for most HIV testing.[35] Accessory genes carried by HIV include tat, rev, nef, vif, vpr, and vpu (for HIV-1) or vpx (for HIV-2). The rev gene encodes for a regulatory protein which switches the processing of viral RNA transcripts to a pattern that predominates with established infection, leading to production of viral structural and enzymatic proteins. The long terminal repeat (LTR) serves as a promoter of transcription.[22,30,32,33]

Zellweger syndrome (ZS), neonatal adrenoleukodystrophy (NALD), X-linked adrenoleukodystrophy (X-ALD), and infantile Refsum disease (IRD) are the four main peroxisomal disorders classified by the absence, or a defect in, specific peroxisomal proteins. Zellweger syndrome is considered the most severe of the four most studied peroxisomal disorders, causing a faster and earlier death. Lacking or having defective peroxisomal proteins is especially problematic due to the many functions specific to this organelle such as the breakdown of fatty acids, production of lipids for the nervous system and digestion, and functioning in development of the brain. Peroxisomes contain no DNA, causing all of its defects to be mutations of nuclear genes. This is significant because, as we’ll learn later in this class, nuclear genes code for peroxisomal proteins which are synthesized on cytoplasmic ribosomes to later be imported into the peroxisome. Without proper formation, these proteins will not enter the peroxisomes and remain functionless in the cytosol. Some individuals can still have peroxisomes detected in their cells, but they are non-functional--or cannot properly carry out their duties--without the assistance

HIV is a retrovirus that that contains RNA and is a member of the subfamily of viruses called lentivirus, in this group infection develops slowly. It

Because peroxisomes play a significant role in cell, the deficiency of peroxisomes are dangerous. One of the most life-threatening diseases which are caused by the absence of peroxisomes is Zellweger syndrome. This condition is also called peroxisome deficiency disorders. In the patients with Zellweger syndrome, there are mutations in PEX genes which encoded for peroxisome assembly. Because peroxisomes help cell oxidize the long chain fatty acids, these patients can not oxidize fatty acids and build up bile acid precursors. As a result, the symptoms or peroxisome deficiency disorder are neonatl hypotonia, neurological manifestations such as psychological and motor retardation, seizures; liver diseases such as cirrhosis, hepatomegaly… The outcome of this disease is poor. There are many infants die in the first year of life because of respiratory compromise from

The function of peroxisomes is very crucial to maintain homeostasis in the cell. Peroxisomes contain enzymes that oxidize certain molecules normally found in the cell, notably fatty acids and amino acids. Those oxidation reactions produce hydrogen peroxide, which is the basis of the name peroxisome. However, hydrogen peroxide is potentially toxic to the cell, because it has the ability to react with many other molecules. Therefore, peroxisomes also contain enzymes such as catalase that convert hydrogen peroxide to water and oxygen, thereby neutralizing the toxicity. In that way peroxisomes provide a safe location for the oxidative metabolism of certain molecules. Peroxisomes produce chemicals as well as break them

In addition to transcriptional regulation and epigenetic mechanisms, posttranscriptional regulation by microRNAs is also critically involved in the intracellular signaling of oligodendrocyte differentiation. Studies using transgenic mice in which microRNA processing is specifically disrupted in the oligodendrocyte lineage by way of Dicer enzyme knockout have shown that microRNA processing is indispensible for normal CNS myelination (Dugas et al., 2010), and that in vitro OPCs also fail to differentiate in the absence of mature microRNAs. Specifically, three microRNAs including miR-219, miR-138, and miR-338 are found to be elevated by 1-2 orders of magnitude during OPC differentiation into oligodendrocytes, and that miR-219 when induced alone, is sufficient to promote the differentiation (Dugas et al., 2010). The downstream target of miR-219, ELOVL7, is also identified as a main molecular component involved in the development of the Dicer mutant phenotype (Shin, Shin, McManus, Ptacek, & Fu, 2009), and that overexpression of ELOVL7 results in lipid accumulation, which is in turn suppressed by co-overexpression of miR-219. Other important target genes of the above mentioned microRNAs include PDGFRa, Sox6, and Hes5 (Dugas et al., 2010; X. Zhao et al., 2010), all of which serve to

This study aims to evaluate the prognostic effect of miRNA expression in stage II CRC patients. The research protocol follows the PRISMA-P (the Preferred Reporting

Biology is the science of life, also known as the study of living things. All living things are made up of cells and organelles that function together to help sustain life for themselves. One of these organelles, is the peroxisome which is found in all eukaryotic cells and their function is to help catabolize fatty acids, amino acids, etc (Bronfman, Inestrosa, & Leighton, 1979) Peroxisomes play an essential role in the sustainability of life, but along with many other things in life they are susceptible to defects. Fundamentally, peroxisomes help assist in the metabolic functions of the cell, and can contribute to a series of biogenesis disorders.

Some of the more interesting genomic locations of miRNA genes include those in the Hox clusters. The mir-10 gene lies in the Antennapedia complex of insects and in the orthologous locations in two Hox clusters of mammals [15, 16]. The Hox miRNAs are especially good candidates for having interesting functions in animal development. Nearly all of the cloned miRNAs are conserved in closely related animals such as human and mouse, or C. elegans and C. briggsae [16, 17]. Many mi RNAs are conserved concerved more broadly

The first assay and blot measured HIF-1α promoter activity. The second assay and blot measured HIF-1α mRNA level. The third assay and blot measured HIFα translational initiation levels. The fourth assay and blot measured HIF-1α protein stability. There was no significant difference between co-transfected EV and co-transfected PER2 under either normoxic or hypoxic conditions for any of these four assays, suggesting that PER2 does not affect the condition being measured.The fifth blot measured HIF-1α protein levels. The blot shows PER2 overexpression did not increase the protein levels of HIF-1α. The final assay and blot measured the transactivation activity of HIF-α TAD. The results show, under hypoxic conditions, that PER2 significantly increased the transactivation activity of HIF-α TAD.

MicroRNAs are short regulatory RNAs that modulate gene expression and are expressed in many diseases, including cancer. Studies have shown that microRNAs inhibit the translation and facilitate degradation of their targeted messenger RNAs which makes them a great candidate for the use in cancer therapy (Shahab, 2011, p. 1). Many researchers and scientists are especially finding ways microRNAs can help with epithelial ovarian cancer in means by examining their expression pattern and mechanistic implications of microRNA-383 in which these captivating particles can modify the appearance of almost 30% of the Performing at the post-transcriptional mammalian protein-encoding genes. In this unique process, cells can be known to be complex because of the different functions that are taken upon. Due to the fact that cells have specific functions, in order for it to have the proper genes expressed, gene regulation is enforced throughout the early stages of development in a cell; this enforcement signals that each gene be expressed properly and at the proper time. Because of this process, living organisms are able to respond to each individual environment.

Peroxisomes have an essential function in cell metabolism. [1] They are small, membrane bounded organelles that have at least fifty different enzymes for several metabolic reactions. [2] Their appearance is like lysosomes; however, their main function is oxidation reactions especially oxidation of hydrogen peroxide and producing oxygen and water. There are diseases related and caused by this organelle that can be classified in three groups. [2] First group is a disorder duo to overall dysfunction of peroxisomes, like zellweger