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Small Nucleolar RNA-derived MicroRNA
In molecular biology, small nucleolar RNA derived microRNAs are microRNAs (miRNA) derived from small nucleolar RNA (snoRNA). MicroRNAs are usually derived from precursors known as pre-miRNAs, these pre-miRNAs are recognised and cleaved from a pri-miRNA precursor by the Pasha and Drosha proteins. However some microRNAs, mirtrons, are known to be derived from introns via a different pathway which bypasses Pasha and Drosha. Some microRNAs are also known to be derived from small nucleolar RNA. Discovery Small nucleolar RNA derived microRNA was first described in 2008. The protozoal intestinal parasite ''Giardia lamblia'' lacks the Drosha protein involved in pre-miRNA cleavage from pri-miRNA. However the miRNA processing protein dicer is found in ''Giardia''. A 26 nucleotide RNA, miR2, is processed from the ''Giardia lamblia'' snoRNA GlsR17 by dicer. MiR2 is a microRNA which may regulate the expression of variant surface proteins. Also in 2008, a small RNA was found to be cleaved from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MicroRNA
Micro ribonucleic acid (microRNA, miRNA, μRNA) are small, single-stranded, non-coding RNA molecules containing 21–23 nucleotides. Found in plants, animals, and even some viruses, miRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression. miRNAs base-pair to complementary sequences in messenger RNA (mRNA) molecules, then silence said mRNA molecules by one or more of the following processes: * Cleaving the mRNA strand into two pieces. * Destabilizing the mRNA by shortening its poly(A) tail. * Reducing translation of the mRNA into proteins. In cells of humans and other animals, miRNAs primarily act by destabilizing the mRNA. miRNAs resemble the small interfering RNAs (siRNAs) of the RNA interference (RNAi) pathway, except miRNAs derive from regions of RNA transcripts that fold back on themselves to form short stem-loops (hairpins), whereas siRNAs derive from longer regions of double-stranded RNA. The human genome may encode ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleotide
Nucleotides are Organic compound, organic molecules composed of a nitrogenous base, a pentose sugar and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all Life, life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common Nutrient, nutrients by the liver. Nucleotides are composed of three subunit molecules: a nucleobase, a pentose, five-carbon sugar (ribose or deoxyribose), and a phosphate group consisting of one to three phosphates. The four nucleobases in DNA are guanine, adenine, cytosine, and thymine; in RNA, uracil is used in place of thymine. Nucleotides also play a central role in metabolism at a fundamental, cellular level. They provide chemical energy—in the form of the nucleoside triphosphates, adenosine triphosphate (ATP), guanosine triphosphate (GTP), cytidine triphosphate (CTP), and uridine triph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MicroRNA
Micro ribonucleic acid (microRNA, miRNA, μRNA) are small, single-stranded, non-coding RNA molecules containing 21–23 nucleotides. Found in plants, animals, and even some viruses, miRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression. miRNAs base-pair to complementary sequences in messenger RNA (mRNA) molecules, then silence said mRNA molecules by one or more of the following processes: * Cleaving the mRNA strand into two pieces. * Destabilizing the mRNA by shortening its poly(A) tail. * Reducing translation of the mRNA into proteins. In cells of humans and other animals, miRNAs primarily act by destabilizing the mRNA. miRNAs resemble the small interfering RNAs (siRNAs) of the RNA interference (RNAi) pathway, except miRNAs derive from regions of RNA transcripts that fold back on themselves to form short stem-loops (hairpins), whereas siRNAs derive from longer regions of double-stranded RNA. The human genome may encode ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinases
In biochemistry, a kinase () is an enzyme that catalysis, catalyzes the transfer of phosphate groups from High-energy phosphate, high-energy, phosphate-donating molecules to specific Substrate (biochemistry), substrates. This process is known as phosphorylation, where the high-energy adenosine triphosphate, ATP molecule donates a phosphate group to the substrate (biology), substrate molecule. As a result, kinase produces a phosphorylated substrate and Adenosine diphosphate, ADP. Conversely, it is referred to as dephosphorylation when the phosphorylated substrate donates a phosphate group and ADP gains a phosphate group (producing a dephosphorylated substrate and the high energy molecule of ATP). These two processes, phosphorylation and dephosphorylation, occur four times during glycolysis. Kinases are part of the larger family of phosphotransferases. Kinases should not be confused with phosphorylases, which catalyze the addition of inorganic phosphate groups to an acceptor, nor w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SnoRNA
In molecular biology, small nucleolar RNAs (snoRNAs) are a class of small RNA molecules that primarily guide chemical modifications of other RNAs, mainly ribosomal RNAs, transfer RNAs and small nuclear RNAs. There are two main classes of snoRNA, the C/D box snoRNAs, which are associated with methylation, and the H/ACA box snoRNAs, which are associated with pseudouridylation. SnoRNAs are commonly referred to as guide RNAs but should not be confused with the guide RNAs that direct RNA editing in trypanosomes or the guide RNAs (gRNAs) used by Cas9 for CRISPR gene editing. snoRNA guided modifications After transcription, nascent rRNA molecules (termed pre-rRNA) undergo a series of processing steps to generate the mature rRNA molecule. Prior to cleavage by exo- and endonucleases, the pre-rRNA undergoes a complex pattern of nucleoside modifications. These include methylations and pseudouridylations, guided by snoRNAs. *Methylation is the attachment or substitution of a methyl group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RRNA
Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosomal DNA (rDNA) and then bound to ribosomal proteins to form SSU rRNA, small and LSU rRNA, large ribosome subunits. rRNA is the physical and mechanical factor of the ribosome that forces transfer RNA (tRNA) and messenger RNA (mRNA) to process and Translation (biology), translate the latter into proteins. Ribosomal RNA is the predominant form of RNA found in most cells; it makes up about 80% of cellular RNA despite never being translated into proteins itself. Ribosomes are composed of approximately 60% rRNA and 40% ribosomal proteins, though this ratio differs between Prokaryote, prokaryotes and Eukaryote, eukaryotes. Structure Although the primary structure of rRNA sequences can vary across organisms, Base pair, base-pairing within these sequ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Small Cajal Body-specific RNA
Small Cajal body-specific RNAs (scaRNAs) are a class of small nucleolar RNAs (snoRNAs) that specifically localise to the Cajal body, a nuclear organelle (cellular sub-organelle) involved in the biogenesis of small nuclear ribonucleoproteins (snRNPs or snurps). ScaRNAs guide the modification (methylation and pseudouridylation) of RNA polymerase II transcribed spliceosomal RNAs U1, U2, U4, U5 and U12. The first scaRNA identified was U85. It is unlike typical snoRNAs in that it is a composite C/D box and H/ACA box snoRNAs and can guide both pseudouridylation and 2′-''O''-methylation. Not all scaRNAs are composite C/D and H/ACA box snoRNA and most scaRNAs are structurally and functionally indistinguishable from snoRNAs, directing ribosomal RNA (rRNA) modification in the nucleolus. ''Drosophila'' scaRNAs Several studies identified scaRNAs in ''Drosophila.'' One of the studies showed that several ''Drosophila'' scaRNAs could function equally well in the nucleoplasm of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Expression (genetics)
Gene expression is the process (including its regulation) by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, proteins or non-coding RNA, and ultimately affect a phenotype. These products are often proteins, but in non-protein-coding genes such as transfer RNA (tRNA) and small nuclear RNA (snRNA), the product is a functional non-coding RNA. The process of gene expression is used by all known life—eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea), and viruses—to generate the macromolecular machinery for life. In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype, ''i.e.'' observable trait. The genetic information stored in DNA represents the genotype, whereas the phenotype results from the "interpretation" of that information. Such phenotypes are often displayed by the synthesis of proteins that control the or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicer
Dicer, also known as endoribonuclease Dicer or helicase with RNase motif, is an enzyme that in humans is encoded by the gene. Being part of the RNase III family, Dicer cleaves double-stranded RNA (dsRNA) and pre-microRNA (pre-miRNA) into short double-stranded RNA fragments called small interfering RNA and microRNA, respectively. These fragments are approximately 20–25 base pairs long with a two-base overhang on the 3′-end. Dicer facilitates the activation of the RNA-induced silencing complex (RISC), which is essential for RNA interference. RISC has a catalytic component Argonaute, which is an endonuclease capable of degrading messenger RNA (mRNA). Discovery Dicer was given its name in 2001 by Stony Brook PhD student Emily Bernstein while conducting research in Gregory Hannon's lab at Cold Spring Harbor Laboratory. Bernstein sought to discover the enzyme responsible for generating small RNA fragments from double-stranded RNA. Dicer's ability to generate aroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Small Nucleolar RNA
In molecular biology, small nucleolar RNAs (snoRNAs) are a class of small RNA molecules that primarily guide chemical modifications of other RNAs, mainly ribosomal RNAs, transfer RNAs and small nuclear RNAs. There are two main classes of snoRNA, the C/D box snoRNAs, which are associated with methylation, and the H/ACA box snoRNAs, which are associated with pseudouridylation. SnoRNAs are commonly referred to as guide RNAs but should not be confused with the guide RNAs that direct RNA editing in trypanosomes or the guide RNAs (gRNAs) used by Cas9 for CRISPR gene editing. snoRNA guided modifications After transcription, nascent rRNA molecules (termed pre-rRNA) undergo a series of processing steps to generate the mature rRNA molecule. Prior to cleavage by exo- and endonucleases, the pre-rRNA undergoes a complex pattern of nucleoside modifications. These include methylations and pseudouridylations, guided by snoRNAs. *Methylation is the attachment or substitution of a methyl group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giardia Lamblia
''Giardia duodenalis'', also known as ''Giardia intestinalis'' and ''Giardia lamblia'', is a flagellated Parasitism, parasitic protozoan microorganism of the genus ''Giardia'' that colonizes the small intestine, causing a diarrheal condition known as giardiasis. The parasite attaches to the intestinal epithelium by a ventral disc (''syn''. sucker (zoology), adhesive disc or sucker), and reproduction, reproduces via Fission (biology)#Binary_fission, binary fission. ''G. duodenalis'' is a non-invasive parasite, that does not spread to other parts of the gastrointestinal tract, but remains confined to the lumen (anatomy), lumen of the small intestine. The parasite exists in two forms; Trophozoite, trophozoites and Microbial cyst, cysts. The microorganism can undergo encystation, transforming into a dormant Microbial cyst, cyst that enables it to survive outside of its Host (biology), host. ''Giardia'' trophozoites are Anaerobic organism, anaerobic, and absorb their nutrients from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intestinal Parasite
An intestinal parasite infection is a condition in which a parasite infects the gastro-intestinal tract of humans and other animals. Such parasites can live anywhere in the body, but most prefer the intestinal wall. Routes of exposure and infection include ingestion of undercooked meat, drinking infected water, fecal–oral transmission and skin absorption. Some types of helminths and protozoa are classified as intestinal parasites that cause infection—those that reside in the intestines. These infections can damage or sicken the host (humans or other animals). If the intestinal parasite infection is caused by helminths, the infection is called helminthiasis. Signs and symptoms Signs and symptoms depend on the type of infection. Intestinal parasites produce a variety of symptoms in those affected, most of which manifest themselves in gastrointestinal complications and general weakness. Gastrointestinal conditions include inflammation of the small and/or large intestine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
