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Epigenetics And Melanoma
Melanoma is a rare but aggressive malignant cancer that originates from melanocytes. These melanocytes are cells found in the basal layer of the epidermis that produce melanin under the control of melanocyte-stimulating hormone. Despite the fact that melanoma represents only a small number of all skin cancers, it is the cause of more than 50% of cancer-related deaths. The high metastatic qualities and death rate, and also its prevalence among people of younger ages have caused melanoma to become a highly researched malignant cancer. Epigenetic modifications are suspected to influence the emergence of many types of cancer-related diseases, and are also suspected to have a role in the development of melanoma. In the last few years, chemical alterations in the genome have become more evident, and these alterations can be critical in the development of malignancy. This alteration process is referred to as epigenetics (Patino et al. 2008). Epigenetics is the term used to refer to stabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanoma
Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In very rare cases melanoma can also happen in the lung which is known as primary pulmonary melanoma and only happens in 0.01% of primary lung tumors. In women, melanomas most commonly occur on the legs; while in men, on the back. Melanoma is frequently referred to as malignant melanoma. However, the medical community stresses that there is no such thing as a 'benign melanoma' and recommends that the term 'malignant melanoma' should be avoided as redundant. About 25% of melanomas develop from nevus, moles. Changes in a mole that can indicate melanoma include increaseespecially rapid increasein size, irregular edges, change in color, itchiness, or nevus#Classification, skin breakdown. The primary cause of melanoma is ultraviolet light (UV) exposure in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Methylation
DNA methylation is a biological process by which methyl groups are added to the DNA molecule. Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter (genetics), promoter, DNA methylation typically acts to repress gene Transcription (genetics), transcription. In mammals, DNA methylation is essential for normal development and is associated with a number of key processes including genomic imprinting, X-chromosome inactivation, repression of transposable elements, aging, and carcinogenesis. As of 2016, two nucleobases have been found on which natural, enzymatic DNA methylation takes place: adenine and cytosine. The modified bases are N6-methyladenine,D. B. Dunn, J. D. Smith: "The occurrence of 6-methylaminopurine in deoxyribonucleic acids". In: ''Biochem J.'' 68(4), Apr 1958, S. 627–636. [//www.ncbi.nlm.nih.gov/pubmed/13522672?dopt=Abstract PMID 13522672]. . 5-methylcytosineB. F. Vanyushin, S. G. Tkacheva, A. N. Belozers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ku86
Ku80 is a protein that, in humans, is encoded by the ''XRCC5'' gene. Together, Ku70 and Ku80 make up the Ku heterodimer, which binds to DNA double-strand break ends and is required for the non-homologous end joining (NHEJ) pathway of DNA repair. It is also required for V(D)J recombination, which utilizes the NHEJ pathway to promote antigen diversity in the mammalian immune system. In addition to its role in NHEJ, Ku is required for telomere length maintenance and subtelomeric gene silencing. Ku was originally identified when patients with systemic lupus erythematosus were found to have high levels of autoantibodies to the protein. Nomenclature Ku80 has been referred to by several names including: * Lupus Ku autoantigen protein p80 * ATP-dependent DNA helicase 2 subunit 2 * X-ray repair complementing defective repair in Chinese hamster cells 5 * X-ray repair cross-complementing 5 (XRCC5) Epigenetic repression The protein expression level of Ku80 can be repressed by ep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ku70
Ku70 is a heterodimeric protein made up of Ku70 and Ku80, which together form Ku. In humans, is encoded by the ''XRCC6'' gene. Ku70 plays a critical role in the DNA repair, maintenance and many other cellular processes. Function Together, Ku70 and Ku80 make up the Ku heterodimer form a quasi-symmetric structure, which encircles the double-stranded DNA. The DNA double-strand break ends and is required for the non-homologous end joining (NHEJ) of the DNA repair pathway. It is also required for V(D)J recombination, which utilizes the NHEJ pathway to promote antigen diversity in the mammalian immune system. Ku70 is key for sensing and responding to cytosolic DNA, which is essential for the indication of infection. Within the heterodimer, Ku70 specifically binds directly to broken ends of double-stranded DNA breaks, or DSBs. Then together, Ku70 and Ku80 will tightly form a ring-like structure around the DNA strand, preventing further degradation. These steps are essential for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histone Acetylation
Histone acetyltransferases (HATs) are enzymes that acetylate conserved lysine amino acids on histone proteins by transferring an acetyl group from acetyl-CoA to form ε-''N''-acetyllysine. DNA is wrapped around histones, and, by transferring an acetyl group to the histones, genes can be turned on and off. In general, histone acetylation increases gene expression. In general, histone acetylation is linked to transcriptional activation and associated with euchromatin. Euchromatin, which is less densely compact, allows transcription factors to bind more easily to regulatory sites on DNA, causing transcriptional activation. When it was first discovered, it was thought that acetylation of lysine neutralizes the positive charge normally present, thus reducing affinity between histone and (negatively charged) DNA, which renders DNA more accessible to transcription factors. Research has emerged, since, to show that lysine acetylation and other posttranslational modifications of hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterochromatin
Heterochromatin is a tightly packed form of DNA or '' condensed DNA'', which comes in multiple varieties. These varieties lie on a continuum between the two extremes of constitutive heterochromatin and facultative heterochromatin. Both play a role in the expression of genes. Because it is tightly packed, it was thought to be inaccessible to polymerases and therefore not transcribed; however, according to Volpe et al. (2002), and many other papers since, much of this DNA is in fact transcribed, but it is continuously turned over via RNA-induced transcriptional silencing (RITS). Recent studies with electron microscopy and OsO4 staining reveal that the dense packing is not due to the chromatin. Constitutive heterochromatin can affect the genes near itself (e.g. position-effect variegation). It is usually repetitive and forms structural functions such as centromeres or telomeres, in addition to acting as an attractor for other gene-expression or repression signals. Facultativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histone Methylation
Histone methylation is a process by which methyl groups are transferred to amino acids of histone proteins that make up nucleosomes, which the DNA double helix wraps around to form chromosomes. Methylation of histones can either increase or decrease transcription of genes, depending on which amino acids in the histones are methylated, and how many methyl groups are attached. Methylation events that weaken chemical attractions between histone tails and DNA increase transcription because they enable the DNA to uncoil from nucleosomes so that transcription factor proteins and RNA polymerase can access the DNA. This process is critical for the regulation of gene expression that allows different cells to express different genes. Function Histone methylation, as a mechanism for modifying chromatin structure is associated with stimulation of neural pathways known to be important for formation of long-term memories and learning. Histone methylation is crucial for almost all phases of anim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SYK (gene)
Tyrosine-protein kinase SYK, also known as spleen tyrosine kinase, is an enzyme which in humans is encoded by the ''SYK'' gene. Function SYK, along with ZAP70, is a member of the Syk family of tyrosine kinases. These cytoplasmic non-receptor tyrosine kinases share a characteristic dual SH2 domain separated by a linker domain. However, activation of SYK relies less on phosphorylation by Src family kinases than ZAP70. SYK and ZAP70 share a common evolutionary origin and split from a common ancestor in the jawed vertebrates. While Syk and ZAP70 are primarily expressed in hematopoietic tissues, a variety of tissues express Syk. Within B and T cells, respectively, Syk and ZAP70 transmit signals from the B-cell receptor and T-cell receptor. Syk plays a similar role in transmitting signals from a variety of cell surface receptors including CD74, Fc receptor, and integrins. Function during development Mice that lack Syk completely (Syk−/−, Syk-knockout) die during embryoni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDK6
Cell division protein kinase 6 (CDK6) is an enzyme encoded by the ''CDK6'' gene. It is regulated by cyclins, more specifically by Cyclin D proteins and Cyclin-dependent kinase inhibitor proteins. The protein encoded by this gene is a member of the cyclin-dependent kinase, (CDK) family, which includes CDK4. CDK family members are highly similar to the gene products of ''Saccharomyces cerevisiae'' cdc28, and ''Schizosaccharomyces pombe'' cdc2, and are known to be important regulators of cell cycle progression in the point of regulation named R or restriction point. This kinase is a catalytic subunit of the protein kinase complex, important for the G1 phase progression and G1/S transition of the cell cycle and the complex is composed also by an activating sub-unit; the cyclin D. The activity of this kinase first appears in mid-G1 phase, which is controlled by the regulatory subunits including D-type cyclins and members of INK4 family of CDK inhibitors. This kinase, as well as CDK4, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDK4
Cyclin-dependent kinase 4 (CDK4), also known as cell division protein kinase 4, is an enzyme that is encoded by the ''CDK4'' gene in humans. CDK4 is a member of the cyclin-dependent kinase family, a group of serine/threonine kinases which regulate the cell cycle. CDK4 regulates the G1/S transition by contributing to the phosphorylation of retinoblastoma (RB) protein, which leads to the release of protein factors like E2F1 that promote S-phase progression. It is regulated by cyclins like cyclin D proteins, regulatory kinases, and cyclin kinase inhibitors (CKIs). Dysregulation of the CDK4 pathway is common in many cancers, and CDK4 is a new therapeutic target in cancer treatment. Structure The CDK4 gene is located on chromosome 12 in humans. The gene is composed of 4,583 base pairs which together code for the 303 amino acid protein with a molecular mass of 33,730 Da. All CDK proteins, including CDK4, have two lobes: the smaller N-terminal lobe (which contains an inhibitory G-l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumor Suppressor Gene
A tumor suppressor gene (TSG), or anti-oncogene, is a gene that regulates a cell (biology), cell during cell division and replication. If the cell grows uncontrollably, it will result in cancer. When a tumor suppressor gene is mutated, it results in a loss or reduction in its function. In combination with other genetic mutations, this could allow the cell to grow abnormally. The Loss-of-function mutation, loss of function for these genes may be even more significant in the development of human cancers, compared to the activation of oncogenes. TSGs can be grouped into the following categories: caretaker genes, gatekeeper genes, and more recently landscaper genes. Caretaker genes ensure stability of the genome via DNA repair and subsequently when mutated allow mutations to accumulate. Meanwhile, gatekeeper genes directly regulate cell growth by either inhibiting cell cycle progression or inducing apoptosis. Lastly, landscaper genes regulate growth by contributing to the surrounding e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Silencing
Gene silencing is the regulation of gene expression in a cell to prevent the expression of a certain gene. Gene silencing can occur during either Transcription (genetics), transcription or Translation (biology), translation and is often used in research. In particular, methods used to silence genes are being increasingly used to produce therapeutics to combat cancer and other diseases, such as infectious diseases and neurodegenerative disorders. Gene silencing is often considered the same as gene knockdown. When genes are silenced, their expression is reduced. In contrast, when genes are knocked out, they are completely erased from the organism's genome and, thus, have no expression. Gene silencing is considered a gene knockdown mechanism since the methods used to silence genes, such as RNAi, CRISPR, or siRNA, generally reduce the expression of a gene by at least 70% but do not eliminate it. Methods using gene silencing are often considered better than gene knockouts since they allo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
