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Smaug (protein)
Smaug is a RNA-binding protein in ''Drosophila'' that helps in maternal to zygotic transition (MZT). The protein is named after the fictional character Smaug, the dragon in J. R. R. Tolkien, J.R.R. Tolkien's 1937 novel ''The Hobbit''. The MZT ends with the Midblastula, midblastula transition (MBT), which is defined as the first developmental event in ''Drosophila'' that depends on zygotic mRNA. In ''Drosophila'', the initial developmental events are controlled by maternal mRNAs like ''Hsp83'', ''nanos (gene), nanos'', ''string'', ''Pgc'', and ''cyclin B'' mRNA. Degradation of these mRNAs, which is expected to terminate maternal control and enable zygotic control of embryogenesis, happens at interphase of nuclear division cycle 14. During this transition smaug protein targets the maternal mRNA for destruction using MicroRNA, miRs. Thus activating the zygotic genes. Smaug is expected to play a role in expression of three miRNAs – ''miR-3, miR-6, miR-309'' and ''miR-286'' during MZ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Translation Control Of Nanos MRNA By Smaug Protein
Translation is the communication of the semantics, meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The English language draws a terminological distinction (which does not exist in every language) between ''translating'' (a written text) and ''interpreting'' (oral or Sign language, signed communication between users of different languages); under this distinction, translation can begin only after the appearance of writing within a language community. A translator always risks inadvertently introducing source-language words, grammar, or syntax into the target-language rendering. On the other hand, such "spill-overs" have sometimes imported useful source-language calques and loanwords that have enriched target languages. Translators, including early translators of sacred texts, have helped shape the very languages into which they have translated. Becau ... [...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] |
SAMD4A
Sterile alpha motif domain containing 4A is a protein that in humans is encoded by the SAMD4A gene. Function Sterile alpha motifs (SAMs) in proteins such as SAMD4A are part of an RNA-binding domain that functions as a posttranscriptional regulator by binding to an RNA sequence motif known as the Smaug recognition element, which was named after the ''Drosophila ''Drosophila'' (), from Ancient Greek δρόσος (''drósos''), meaning "dew", and φίλος (''phílos''), meaning "loving", is a genus of fly, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or p ...'' Smaug protein (Baez and Boccaccio, 2005 ubMed 16221671. upplied by OMIM, Mar 2008 References Further reading * * * * {{gene-14-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deadenylation
Polyadenylation is the addition of a poly(A) tail to an RNA transcript, typically a messenger RNA (mRNA). The poly(A) tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In eukaryotes, polyadenylation is part of the process that produces mature mRNA for translation (biology), translation. In many bacteria, the poly(A) tail promotes degradation of the mRNA. It, therefore, forms part of the larger process of gene expression. The process of polyadenylation begins as the transcription (genetics), transcription of a gene Transcription (genetics)#Termination, terminates. The Directionality (molecular biology), 3′-most segment of the newly made pre-mRNA is first cleaved off by a protein complex, set of proteins; these proteins then synthesize the poly(A) tail at the RNA's 3′ end. In some genes these proteins add a poly(A) tail at one of several possible sites. Therefore, polyadenylation can produce more than one tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CCR4-Not
Carbon Catabolite Repression 4—Negative On TATA-less, or CCR4-Not, is a multiprotein complex that functions in gene expression. The complex has multiple enzymatic activities as both a poly(A) 3′-5′ exonuclease and a ubiquitin ligase. The exonuclease activity of CCR4-Not shortens the poly(A) tail found at 3' end of almost every eukaryotic mRNA. The complex is present both in the nucleus where it regulates transcription and in the cytoplasm where it associates with translating ribosomes and RNA processing bodies. In mammalian cell, it has a function in the regulation of the cell cycle, chromatin modification, activation and inhibition of transcription initiation, control of transcription elongation, RNA export, nuclear RNA surveillance, and DNA damage repair in nucleus. Ccr4–Not complex plays an important role in mRNA decay and protein quality control in the cytoplasm. Subunits The human CCR4-Not complex is composed of structural (non-catalytic) subunits and those t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4E
Eukaryotic translation initiation factor 4E, also known as eIF4E, is a protein in humans encoded by the ''EIF4E'' gene. eIF4E plays a central role in translation initiation and is involved in regulating protein synthesis. Its activity influences a range of biological processes and disease states, making it an important target for therapeutic development, particularly in disorders characterized by aberrant protein production. Discovery eIF4E was discovered as a cytoplasmic cap binding protein functioning in translation by Witold Filipowicz at al. In 1976. Two years later, in 1978, Sonenberg et al. confirmed Filipowicz et al.’s findings by repeating the same experiments and adding a crosslinking chemical to increase the stability of the mRNA-protein complex. This has been confirmed by numerous scientists in their published articles such as Katherine L. B. Borden, Michael J. Osborne and Katherine L.B. Borden. Structure Most eukaryote, eukaryotic cellular Messenger RNA, mRNAs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4G
Eukaryotic translation initiation factor 4 G (eIF4G) is a protein involved in eukaryotic translation initiation and is a component of the eIF4F cap-binding complex. Orthologs of eIF4G have been studied in multiple species, including humans, yeast, and wheat. However, eIF4G is exclusively found in domain Eukarya, and not in domains Bacteria or Archaea, which do not have capped mRNA. As such, eIF4G structure and function may vary between species, although the human EIF4G1 has been the focus of extensive studies. (Other human paralogs are EIF4G2 and EIF4G3.) Across species, eIF4G strongly associates with eIF4E, the protein that directly binds the mRNA cap. Together with the RNA helicase protein eIF4A, these form the eIF4F complex. Within the cell eIF4G is found primarily in the cytoplasm, usually bound to eIF4E; however, it is also found in the nucleus, where its function is unknown. It may have a role in nonsense-mediated decay. History eIF4G stands for eukaryotic initiation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanos 3′ UTR Translation Control Element
Nanos 3′ UTR translation control element is a cis-regulatory element in the 3′ untranslated region (3′ UTR) of the messenger RNA which encodes the Nanos protein. The Nanos protein in ''Drosophila'' is required for correct morphogenesis (anterior/posterior patterning) in the ''Drosophila'' embryo. Translation of the Nanos mRNA is repressed in the bulk cytoplasm and activated in the posterior region. The translation control element (TCE) in the 3'UTR forms a Y-shaped secondary structure Protein secondary structure is the local spatial conformation of the polypeptide backbone excluding the side chains. The two most common Protein structure#Secondary structure, secondary structural elements are alpha helix, alpha helices and beta ..., part of which is recognised by the Smaug protein and leads to translational repression. References External links * Cis-regulatory RNA elements {{molecular-cell-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclin B
Cyclin B is a member of the cyclin family. Cyclin B is a mitotic cyclin. The amount of cyclin B (which binds to Cdk1) and the activity of the cyclin B-Cdk complex rise through the cell cycle until mitosis, where they fall abruptly due to degradation of cyclin B (Cdk1 is constitutively present). The complex of Cdk and cyclin B is called maturation promoting factor or mitosis promoting factor (MPF). Function Cyclin B is necessary for the progression of the cells into and out of M phase of the cell cycle. At the end of S phase the phosphatase cdc25c dephosphorylates tyrosine15 and this activates the cyclin B/CDK1 complex. Upon activation the complex is shuttled to the nucleus where it serves to trigger for entry into mitosis. However, if DNA damage is detected alternative proteins are activated which results in the inhibitory phosphorylation of cdc25c and therefore cyclinB/CDK1 is not activated. In order for the cell to progress out of mitosis, the degradation of cyclin B i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA-binding Protein
RNA-binding proteins (often abbreviated as RBPs) are proteins that bind to the double or single stranded RNA in cell (biology), cells and participate in forming ribonucleoprotein complexes. RBPs contain various structural motifs, such as RNA recognition motif (RRM), dsRNA binding domain, zinc finger and others. They are cytoplasmic and cell nucleus, nuclear proteins. However, since most mature RNA is exported from the nucleus relatively quickly, most RBPs in the nucleus exist as complexes of protein and Precursor mRNA, pre-mRNA called heterogeneous ribonucleoprotein particles (hnRNPs). RBPs have crucial roles in various cellular processes such as: cellular function, transport and localization. They especially play a major role in post-transcriptional control of RNAs, such as: RNA splicing, splicing, polyadenylation, mRNA stabilization, mRNA Subcellular localization, localization and Translation (biology), translation. Eukaryote, Eukaryotic cells express diverse RBPs with unique RN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanos (gene)
''Drosophila'' embryogenesis, the process by which ''Drosophila'' (fruit fly) embryos form, is a favorite model organism, model system for genetics and developmental biology. The study of its embryogenesis unlocked the century-long puzzle of how development was controlled, creating the field of evolutionary developmental biology. The small size, short generation time, and large brood size make it ideal for genetic studies. Transparent embryos facilitate developmental studies. ''Drosophila melanogaster'' was introduced into the field of genetic experiments by Thomas Hunt Morgan in 1909. Life cycle ''Drosophila'' display a holometabolous method of development, meaning that they have three distinct stages of their post-embryonic life cycle, each with a radically different body plan: larva, pupa and finally, adult. The machinery necessary for the function and smooth transition between these three phases develops during embryogenesis. During embryogenesis, the larval stage fly will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Midblastula
In developmental biology, midblastula or midblastula transition (MBT) occurs during the blastula stage of embryonic development in non-mammals. During this stage, the embryo is referred to as a blastula. The series of changes to the blastula that characterize the midblastula transition include activation of zygotic gene transcription, slowing of the cell cycle, increased asynchrony in cell division, and an increase in cell motility. Blastula Before MBT Before the embryo undergoes the midblastula transition it is in a state of fast and constant replication of cells. The cell cycle is very short. The cells in the zygote are also replicating synchronously, always undergoing cell division at the same time. The zygote is not producing its own mRNA but rather it is using mRNAs that were produced in the mother and loaded into the oocyte in order to produce proteins necessary for zygotic growth. The zygotic DNA (genetic material) is not being used because it is repressed through a varie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
