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The_role_of_DNA_in_protein_synthesis_(

In the synthesis of proteins, there are actually three types of RNA that participate and play different roles:a.

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The_role_of_DNA_in_protein_synthesis_(

Protein synthesis is accomplished through a process called translation. After is transcribed into a messenger (mRNA) molecule during , the mRNA must be translated to produce a . In translation, mRNA along with (tRNA) and work together to produce proteins.

Transcription proceeds as RNAP inserts complementary RNA bases opposite the coding strand of DNA.

At least three major mechanisms are known fordynamic modification of chromatin organization: i) chromatinremodelling by ATP-dependent complexes (); ii) post-translational modificationof histone proteins (), andiii) replacement of histone isotypes present in chromatin withother isotypes (). During ratbrain development, at least histones H3.3, a core histone variant,and H1°, a linker histone variant, have been shown to accumulateduring the terminal differentiation of nerve cells (,), in the absence of gene activitychanges. Post-transcriptional regulation of the expression of thesetwo histones probably depends on the activity of a group ofRNA-binding proteins (,),some of which have been identified and cloned (,). Among these proteins, one wasalready known as Purkinje cell-expressed peptide (PEP-19, or PCP-4in humans), but is also expressed in a neuron-specific manner inother brain regions (,).

What Is the Role of RNA in Protein Synthesis

The direct synthesis of ...

RPs are often regulated in surprisinglysophisticated manner and several RPs possess extra-ribosomalfunctions. In addition to their roles in ribosome biogenesis andmature ribosome function, some RPs are involved in DNA repair,transcription, RNA processing and apoptosis (,–). A few of these extra ribosomalfunctions are relevant to discuss in the context of cancerdevelopment. To begin with, a number of RPs may affect cell growthto promote cancer cell proliferation. For example, overexpressionof RPS3A leads to the transformation of mouse NIH3T3 cells and theformation of tumors in nude mice (). Another example is RPS13 (uS15)that promotes gastric cancer growth by decreasing levels of p27Kip1(). Upregulation of RPS13accelerated the growth, enhanced colony formationand soft agar growth, and promoted tumor formationwhereas downregulation of RPS13 in gastric cancer cells led toG arrest ().RPS13 as well as RPL23 (uL14) may also suppress drug-inducedapoptosis of gastric cancer cells (). Growth inhibitory functions of RPshave been described as well. The most obvious examples are perhapsRPL5 and RPL11 that when overexpressed inhibit MDM2 (). Many other RPs including RPS15also bind MDM2 and may impact on the p53 response (,). Decreased levels of RPL41 (eL41)led to anchorage-independent growth of NIH3T3 cells in soft agarand increased tumor growth in mice (), while in contrast the enforcedexpression of RPL41 triggered cell cycle arrest and sensitizedcancer cells to cisplatin ().One must emphasize that cells are sensitive to enforceddisturbances in the balance of RPs, and even that certain tags whenfused to RPs including GFP, HA or FLAG may prevent or interferewith an RPs assembly into ribosomes (). Therefore, anti-proliferativeeffects stemming from the ectopic overexpression of RPs may beindirect.

There are more elaborate mechanisms relevant tobring up in the context of the cancer-associated mutationsoccurring in RPL5, RPL22 and RPL10. For example, RPL10 has beenlinked to regulation of the oncogenic transcription factor JUN andother non-ribosome related proteins (), and these functions couldpotentially be altered by the RPL10-Arg98Ser mutant withimplications for cancer development. Another intriguing example isthe inactivation of RPL22 that enhances transformation potentialthrough induction of the Lin28B stemness factor (). The mechanism whereby a deficiencyin RPL22 induces Lin28B is not known. RPL22 is an RNA bindingprotein () but it alsoassociates with chromatin and is involved in gene repressionthrough complex formation with linker histone H1 (). The possibility that RPL22 hasspecific functions in gene regulation on a transcriptional levelmust therefore be taken into consideration. This finding, togetherwith the unusual mode of Rpl22 regulation in mice () and a number of links to p53regulation (,,,) suggest that RPL22 is a veryinteresting candidate for use in diagnostic, prognostic andtherapeutic applications related to cancer.

This lesson discusses the role of RNA in protein synthesis

Polymerization on internal, organophilic silica surfaces of dealuminated zeolites and feldspars

Besides RNA-binding proteins, regulation of the mRNAmetabolism also involves non-coding RNAs (ncRNAs). A highproportion of complex genomes gives rise to ncRNAs, among which themost widely studied class is that of miRNAs, small RNAs of ~22nucleotides (nt) that recognize specific sequences present in the3′-UTR of target mRNAs. By binding their target mRNAs, miRNAsmediate post-transcriptional gene silencing, through an increase ofmRNA decay rate and/or inhibition of translation (–). Deregulation of miRNA functions isinvolved in cancer development (–) and in a number of other humandiseases, including neurological syndromes ().

Proteins that do not contain any conventionalRNA-binding domains have been shown to bind RNA. The variety of-acting domains should therefore be larger thanexpected. Examples of proteins, already known for otherwell-established functions, which are also able to bind RNA,include thymidylate synthase (), mitochondrial glutamatedehydrogenase (), cytosolicglyceraldehyde-3-p dehydrogenase (), and the calmodulin-binding proteinPEP-19 (also known as PCP-4 in humans) ().

Chu E and Allegra CJ: The role ofthymidylate synthase as an RNA binding protein. Bioessays.18:191–198. 1996.  :  :
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What are the three roles of RNA in protein synthesis? - …

It seems that glial cells are involved inregulating localized translation in axons, through the horizontaltransfer of ribosomes (). Anattractive working hypothesis can thus be that glial cells alsotransfer into neurons regulatory factors, including transcriptionfactors and RBPs, by sorting them to membrane microvesicles and/orto exosomes, which are then shed from glial cells and fuse withneuronal plasma membranes, delivering their cargoes into nervecells.

Role of RNA and protein synthesis in memory formation.

The most puzzling question is how a given mRNA isspecifically delivered to dendrites (pathway ‘a’ in ) or to the axon (pathway ‘b’ in). Themicrotubule-associated proteins MAP2 and τ are enriched indendrites and axons, respectively; however, it remains to bedetermined whether these and/or other cytoskeleton-associatedproteins have a role in selecting RNPs. As mRNAs already associatewith some RBPs in the nucleus, whether RNA final destination havebeen decided from the beginning remains to be clarified, and ifthis occurs specificity factors should be found among nuclearproteins.

The role of RNA in protein synthesis was suspected already in 1939

Another degenerative pathology that may involvealtered RNA-protein interactions is frontotemporal lobardegeneration (FTLD). FTLD has been classified into two subtypes: i)the first one is characterized by accumulation of themicrotubule-associated protein τ (FTLD-τ) and ii) the second one ischaracterized by inclusion bodies that do not contain τ, butcontain ubiquitin (FTLD-U) (). Recently, a major component ofFTLD-U inclusion bodies has been identified as TAR DNA-bindingprotein-43 (TDP-43), a protein of 43 amino acids encoded onchromosome 1, that can bind both DNA and RNA and functions as asplicing factor. Besides FTLD, amyotrophic lateral sclerosis (ALS)and other related neurodegenerative disorders show inclusions ofTDP-43 and are now known as TDP-43 proteinopathies (). TDP-43 extracted from tissues ofFTLD or ALS is often hyperphosphorylated, ubiquitinated and poorlysoluble (). Of note, severalmutations in ALS have been found in the gene encoding angiogenin(ANG), a secreted RNase ().Angiogenin and TDP-43 have been identified in stress granules,assemblies of different RBPs and mRNAs. Moreover, angiogeninstimulates the transcription of rRNA and is responsible for theproduction of stress-induced small RNAs (). As mentioned in a previoussection, TDP-43 has also been found in ribonucleoprotein complexes,which also contain Stau and FMRP ().

what is the role of dna in protien synthesis? | Yahoo …

Considering their critical functions indevelopment, it is not surprising that altered RNA proteininteractions lead to severe pathologies, such as neurodegenerativediseases and complex neurologic syndromes. Fragile X syndrome(FXS), the most common form of inherited mental retardation,depends on mutation of a gene, located in the X chromosome, whichencodes the already mentioned RNA-binding protein FMRP. Mostclinical cases of FXS result from hyper-expansion and methylationof CGG repeats within the promoter of fmr1 that cause deficit ofits expression. FMRP is involved in the transport and translationalregulation of several dendrite-localized mRNAs, including thatencoding Arc (,), a protein required forhippocampal long-term depression (LTD) and long-term potentiation(LTP) (), and the amyloidprecursor protein (APP) (,), thus FMRP function is related tolong-term synaptic plasticity. FMRP and its target mRNAs formgranule-like complexes that are transported with akinesin-dependent mechanism along microtubules ().

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