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Drosha Ribonuclease III
Drosha is a Class 2 ribonuclease III enzyme that in humans is encoded by the ''DROSHA'' (formerly ''RNASEN'') gene. It is the primary nuclease that executes the initiation step of miRNA processing in the nucleus. It works closely with DGCR8 and in correlation with Dicer. It has been found significant in clinical knowledge for cancer prognosisSlack FJ, Weidhaas JB (December 2008). "MicroRNA in cancer prognosis". ''The New England Journal of Medicine.'' 359 (25): 2720-2. and HIV-1 replication.Swaminathan, G., Navas-Martín, S., & Martín-García, J. (2014). MicroRNAs and HIV-1 infection: antiviral activities and beyond. ''Journal of molecular biology'', ''426''(6), 1178-1197. History Human Drosha was cloned in 2000 when it was identified as a nuclear dsRNA ribonuclease involved in the processing of ribosomal RNA precursors. The other two human enzymes that participate in the processing and activity of miRNA are the Dicer and Argonaute proteins. Recently, proteins like Drosha have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA Interference
RNA interference (RNAi) is a biological process in which RNA molecules are involved in sequence-specific suppression of gene expression by double-stranded RNA, through translational or transcriptional repression. Historically, RNAi was known by other names, including ''co-suppression'', ''post-transcriptional gene silencing'' (PTGS), and ''quelling''. The detailed study of each of these seemingly different processes elucidated that the identity of these phenomena were all actually RNAi. Andrew Fire and Craig C. Mello shared the 2006 Nobel Prize in Physiology or Medicine for their work on RNAi in the nematode worm ''Caenorhabditis elegans'', which they published in 1998. Since the discovery of RNAi and its regulatory potentials, it has become evident that RNAi has immense potential in suppression of desired genes. RNAi is now known as precise, efficient, stable and better than antisense therapy for gene suppression. Antisense RNA produced intracellularly by an expression vector ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Repair
DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA damage, resulting in tens of thousands of individual molecular lesions per cell per day. Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes. Other lesions induce potentially harmful mutations in the cell's genome, which affect the survival of its daughter cells after it undergoes mitosis. As a consequence, the DNA repair process is constantly active as it responds to damage in the DNA structure. When normal repair processes fail, and when cellular apoptosis does not occur, irreparable DNA damage may occur, including double-strand breaks and DNA crosslinkages (interstrand crosslinks or ICLs). This can eventually lead to malig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoplasm
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are cytosol (a gel-like substance), the organelles (the cell's internal sub-structures), and various cytoplasmic inclusions. The cytoplasm is about 80% water and is usually colorless. The submicroscopic ground cell substance or cytoplasmic matrix which remains after exclusion of the cell organelles and particles is groundplasm. It is the hyaloplasm of light microscopy, a highly complex, polyphasic system in which all resolvable cytoplasmic elements are suspended, including the larger organelles such as the ribosomes, mitochondria, the plant plastids, lipid droplets, and vacuoles. Most cellular activities take place within the cytoplasm, such as many metabolic pathways including glycolysis, and proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Nucleus
The cell nucleus (pl. nuclei; from Latin or , meaning ''kernel'' or ''seed'') is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have no nuclei, and a few others including osteoclasts have many. The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and isolates its contents from the cellular cytoplasm; and the nuclear matrix, a network within the nucleus that adds mechanical support. The cell nucleus contains nearly all of the cell's genome. Nuclear DNA is often organized into multiple chromosomes – long stands of DNA dotted with various proteins, such as histones, that protect and organize the DNA. The genes within these chromosomes are structured in such a way to promote cell function. The nucleus maintains the integrity of genes and controls the activities of the cell by regulating g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterogeneous Ribonucleoprotein Particle
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are complexes of RNA and protein present in the cell nucleus during gene transcription and subsequent post-transcriptional modification of the newly synthesized RNA (pre-mRNA). The presence of the proteins bound to a pre-mRNA molecule serves as a signal that the pre-mRNA is not yet fully processed and therefore not ready for export to the cytoplasm. Since most mature RNA is exported from the nucleus relatively quickly, most RNA-binding protein in the nucleus exist as heterogeneous ribonucleoprotein particles. After splicing has occurred, the proteins remain bound to spliced introns and target them for degradation. hnRNPs are also integral to the 40s subunit of the ribosome and therefore important for the translation of mRNA in the cytoplasm. However, hnRNPs also have their own nuclear localization sequences (NLS) and are therefore found mainly in the nucleus. Though it is known that a few hnRNPs shuttle between the cytoplasm and nucle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA-binding Protein EWS
RNA-binding protein EWS is a protein that in humans is encoded by the ''EWSR1'' gene on human chromosome 22, specifically 22q12.2. It is one of 3 proteins in the FET protein family. The q22.2 region of chromosome 22 encodes the N-terminal transactivation domain of the EWS protein and that region may become joined to one of several other chromosomes which encode various transcription factors, see and the FET protein family. The expression of a chimeric protein with the EWS transactivation domain fused to the DNA binding region of a transcription factor generates a powerful oncogenic protein causing Ewing sarcoma and other members of the Ewing family of tumors. These translocations can occur due to chromoplexy, a burst of complex chromosomal rearrangements seen in cancer cells. The normal EWS gene encodes an RNA binding protein closely related to FUS (gene) and TAF15, all of which have been associated to amyotrophic lateral sclerosis. Interactions The EWS protein has been shown ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caenorhabditis Elegans
''Caenorhabditis elegans'' () is a free-living transparent nematode about 1 mm in length that lives in temperate soil environments. It is the type species of its genus. The name is a blend of the Greek ''caeno-'' (recent), ''rhabditis'' (rod-like) and Latin ''elegans'' (elegant). In 1900, Maupas initially named it ''Rhabditides elegans.'' Osche placed it in the subgenus ''Caenorhabditis'' in 1952, and in 1955, Dougherty raised ''Caenorhabditis'' to the status of genus. ''C. elegans'' is an unsegmented pseudocoelomate and lacks respiratory or circulatory systems. Most of these nematodes are hermaphrodites and a few are males. Males have specialised tails for mating that include spicules. In 1963, Sydney Brenner proposed research into ''C. elegans,'' primarily in the area of neuronal development. In 1974, he began research into the molecular and developmental biology of ''C. elegans'', which has since been extensively used as a model organism. It was the first multice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila
''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies (sometimes referred to as "true fruit flies"); tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly. One species of ''Drosophila'' in particular, '' D. melanogaster'', has been heavily used in research in genetics and is a common model organism in developmental biology. The terms "fruit fly" and "''Drosophila''" are often used synonymously with ''D. melanogaster'' in modern biological literature. The entire genus, however, contains more than 1,500 species and is very diverse in appea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pasha (protein)
The microprocessor complex subunit DGCR8 ''( DiGeorge syndrome critical region 8)'' is a protein that in humans is encoded by the gene. In other animals, particularly the common model organisms ''Drosophila melanogaster'' and ''Caenorhabditis elegans'', the protein is known as ''Pasha'' (partner of Drosha). It is a required component of the RNA interference pathway. Function The subunit DGCR8 is localized to the cell nucleus and is required for microRNA (miRNA) processing. It binds to the other subunit Drosha, an RNase III enzyme, to form the microprocessor complex that cleaves a primary transcript known as pri-miRNA to a characteristic stem-loop structure known as a pre-miRNA, which is then further processed to miRNA fragments by the enzyme Dicer. DGCR8 contains an RNA-binding domain and is thought to bind pri-miRNA to stabilize it for processing by Drosha. DGCR8 is also required for some types of DNA repair. Removal of UV-induced DNA photoproducts, during transcript ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DGCR8
The microprocessor complex subunit DGCR8 ''( DiGeorge syndrome critical region 8)'' is a protein that in humans is encoded by the gene. In other animals, particularly the common model organisms '' Drosophila melanogaster'' and ''Caenorhabditis elegans'', the protein is known as ''Pasha'' (partner of Drosha). It is a required component of the RNA interference pathway. Function The subunit DGCR8 is localized to the cell nucleus and is required for microRNA (miRNA) processing. It binds to the other subunit Drosha, an RNase III enzyme, to form the microprocessor complex that cleaves a primary transcript known as pri-miRNA to a characteristic stem-loop structure known as a pre-miRNA, which is then further processed to miRNA fragments by the enzyme Dicer. DGCR8 contains an RNA-binding domain and is thought to bind pri-miRNA to stabilize it for processing by Drosha. DGCR8 is also required for some types of DNA repair. Removal of UV-induced DNA photoproducts, during tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microprocessor Complex
The microprocessor complex is a protein complex involved in the early stages of processing microRNA (miRNA) and RNA interference (RNAi) in animal cells. The complex is minimally composed of the ribonuclease enzyme Drosha and the dimeric RNA-binding protein DGCR8 (also known as Pasha in non-human animals), and cleaves primary miRNA substrates to pre-miRNA in the cell nucleus. Microprocessor is also the smaller of the two multi-protein complexes that contain human Drosha. Composition The microprocessor complex consists minimally of two proteins: Drosha, a ribonuclease III enzyme; and DGCR8, a double-stranded RNA binding protein. (DGCR8 is the name used in mammalian genetics, abbreviated from "DiGeorge syndrome critical region 8"; the homologous protein in model organisms such as flies and worms is called ''Pasha'', for ''Pa''rtner of Dro''sha''.) The stoichiometry of the minimal complex was at one point experimentally difficult to determine, but it has been demonstrated to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
