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Cleavage Factor
__NOTOC__ Cleavage factors are two closely associated protein complexes involved in the cleavage of the 3' untranslated region of a newly synthesized pre-messenger RNA (mRNA) molecule in the process of gene transcription. The cleavage is the first step in adding a polyadenine tail to the pre-mRNA, which is one of the necessary post-transcriptional modifications necessary for producing a mature mRNA molecule. In mammals the two cleavage factors are known as CFIm and CFIIm. The proteins that constitute these complexes are recruited to the cleavage site by cleavage and polyadenylation specificity factor and cleavage stimulatory factor, and form a larger complex that also includes polyadenine polymerase (PAP), which performs the polyadenylation reaction. The CFIm complex Involved in the earliest step for the formation of the active cleavage complex, the CFIm complex is formed by three proteins of 25, 59 and 68 kDa, respectively: *CFIm25 (or CPSF5/NUDT21) *CFIm59 (or CPSF7 Cleavage an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Complex
A protein complex or multiprotein complex is a group of two or more associated polypeptide chains. Protein complexes are distinct from multienzyme complexes, in which multiple catalytic domains are found in a single polypeptide chain. Protein complexes are a form of quaternary structure. Proteins in a protein complex are linked by non-covalent protein–protein interactions. These complexes are a cornerstone of many (if not most) biological processes. The cell is seen to be composed of modular supramolecular complexes, each of which performs an independent, discrete biological function. Through proximity, the speed and selectivity of binding interactions between enzymatic complex and substrates can be vastly improved, leading to higher cellular efficiency. Many of the techniques used to enter cells and isolate proteins are inherently disruptive to such large complexes, complicating the task of determining the components of a complex. Examples of protein complexes include the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3' Untranslated Region
In molecular genetics, the three prime untranslated region (3′-UTR) is the section of messenger RNA (mRNA) that immediately follows the translation termination codon. The 3′-UTR often contains regulatory regions that post-transcriptionally influence gene expression. During gene expression, an mRNA molecule is transcribed from the DNA sequence and is later translated into a protein. Several regions of the mRNA molecule are not translated into a protein including the 5' cap, 5' untranslated region, 3′ untranslated region and poly(A) tail. Regulatory regions within the 3′-untranslated region can influence polyadenylation, translation efficiency, localization, and stability of the mRNA. The 3′-UTR contains both binding sites for regulatory proteins as well as microRNAs (miRNAs). By binding to specific sites within the 3′-UTR, miRNAs can decrease gene expression of various mRNAs by either inhibiting translation or directly causing degradation of the transcript. The 3â ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messenger RNA
In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of synthesizing a protein. mRNA is created during the process of transcription, where an enzyme (RNA polymerase) converts the gene into primary transcript mRNA (also known as pre-mRNA). This pre-mRNA usually still contains introns, regions that will not go on to code for the final amino acid sequence. These are removed in the process of RNA splicing, leaving only exons, regions that will encode the protein. This exon sequence constitutes mature mRNA. Mature mRNA is then read by the ribosome, and, utilising amino acids carried by transfer RNA (tRNA), the ribosome creates the protein. This process is known as translation. All of these processes form part of the central dogma of molecular biology, which describes the flow of genetic information in a biological system. As in DNA, genetic inf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription (genetics)
Transcription is the process of copying a segment of DNA into RNA. The segments of DNA transcribed into RNA molecules that can encode proteins are said to produce messenger RNA (mRNA). Other segments of DNA are copied into RNA molecules called non-coding RNAs (ncRNAs). mRNA comprises only 1–3% of total RNA samples. Less than 2% of the human genome can be transcribed into mRNA ( Human genome#Coding vs. noncoding DNA), while at least 80% of mammalian genomic DNA can be actively transcribed (in one or more types of cells), with the majority of this 80% considered to be ncRNA. Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a complementary language. During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, antiparallel RNA strand called a primary transcript. Transcription proceeds in the following general steps: # RNA polymerase, together with one or more general transcription factors, binds to promoter DNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyadenylation
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. 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 of a gene terminates. The 3′-most segment of the newly made pre-mRNA is first cleaved off by a 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 transcript from a single gene (alternative polyadenylation), similar to alternative splicing. The poly(A) tail is important for the nuclea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post-transcriptional Modification
Transcriptional modification or co-transcriptional modification is a set of biological processes common to most eukaryotic cells by which an RNA primary transcript is chemically altered following transcription from a gene to produce a mature, functional RNA molecule that can then leave the nucleus and perform any of a variety of different functions in the cell. There are many types of post-transcriptional modifications achieved through a diverse class of molecular mechanisms. One example is the conversion of precursor messenger RNA transcripts into mature messenger RNA that is subsequently capable of being translated into protein. This process includes three major steps that significantly modify the chemical structure of the RNA molecule: the addition of a 5' cap, the addition of a 3' polyadenylated tail, and RNA splicing. Such processing is vital for the correct translation of eukaryotic genomes because the initial precursor mRNA produced by transcription often contains both exo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cleavage And Polyadenylation Specificity Factor
Cleavage and polyadenylation specificity factor (CPSF) is involved in the cleavage of the 3' signaling region from a newly synthesized pre-messenger RNA (pre-mRNA) molecule in the process of gene transcription. It is the first protein to bind to the signaling region near the cleavage site of the pre-mRNA, to which the poly(A) tail will be added by polynucleotide adenylyltransferase. The upstream signaling region has the canonical nucleotide sequence AAUAAA, which is highly conserved across the vast majority of pre-mRNAs. A second downstream signaling region, located on the portion of the pre-mRNA that is cleaved before polyadenylation, consists of a GU-rich region required for efficient processing. Structure CPSF is a protein complex, consisting of four proteins: CPSF-73, CPSF-100, CPSF-30 and CPSF-160. CPSF-73 is a zinc-dependent hydrolase which cleaves the mRNA precursor just downstream the polyadenylation signal sequence AAUAAA. CPSF-160 is the largest subunit of CPSF and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cleavage Stimulatory Factor
Cleavage stimulatory factor or cleavage stimulation factor (CstF or CStF) is a heterotrimeric protein, made up of the proteins CSTF1 (55kDa), CSTF2 (64kDa) and CSTF3 (77kDa), totalling about 200 kDa. It is involved in the cleavage of the 3' signaling region from a newly synthesized pre-messenger RNA (mRNA) molecule. CstF is recruited by cleavage and polyadenylation specificity factor (CPSF) and assembles into a protein complex on the 3' end to promote the synthesis of a functional polyadenine tail, which results in a mature mRNA molecule ready to be exported from the cell nucleus to the cytosol for translation. The amount of CstF in a cell is dependent on the phase of the cell cycle, increasing significantly during the transition from G0 phase to S phase in mouse fibroblast and human splenic B cells. Genes * CSTF1, CSTF2 or CSTF2T, CSTF3 Cleavage stimulation factor 77 kDa subunit is a protein that in humans is encoded by the ''CSTF3'' gene. The protein encoded by this gene is o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyadenine Polymerase
In enzymology, a polynucleotide adenylyltransferase () is an enzyme that catalyzes the chemical reaction :ATP + RNA-3'OH \rightleftharpoons pyrophosphate + RNApA-3'OH Thus, the two substrates of this enzyme are ATP and RNA, whereas its two products are pyrophosphate and RNA with an extra adenosine nucleotide at its 3' end. Human genes with this activity include TUT1, MTPAP, PAPOLA, PAPOLB, PAPOLG, TENT2, TENT4A, TENT4B, TENT5C, TENT5D. Naming This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing nucleotide groups (nucleotidyltransferases). The systematic name of this enzyme class is ATP:polynucleotide adenylyltransferase. Other names in common use include: * NTP polymerase * RNA adenylating enzyme * AMP polynucleotidylexotransferase * ATP-polynucleotide adenylyltransferase * ATP:polynucleotidylexotransferase * Poly(A) polymerase * Poly(A) synthetase * Polyadenylate nucleotidyltransferase * Polyadenylate polymerase * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NUDT21
Cleavage and polyadenylation specificity factor subunit 5 (CPSF5) is an enzyme that in humans is encoded by the ''NUDT21'' gene. It belongs to the Nudix family of hydrolases. The protein encoded by this gene is one subunit of the cleavage factor Im complex required for 3' RNA cleavage and polyadenylation processing. The interaction of the protein with the RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ... is one of the earliest steps in the assembly of the 3' end processing complex and facilitates the recruitment of other processing factors. This gene encodes the 25kD subunit of the protein complex, which is composed of four polypeptides. References Further reading * * * * * * * * * * * * * * * * * * * Nudix hydrolases {{gene-16-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CPSF7
Cleavage and polyadenylation specificity factor subunit 7 is a protein that in humans is encoded by the ''CPSF7'' gene. Function CPSF7, also known as CFIm59, is the cleavage factor of two closely associated protein complexes in the 3' untranslated region of a newly synthesized pre-messenger RNA (mRNA) molecule used in gene transcription. CPSF7 is one of three Cleavage and polyadenylation specificity factors (CPSF), the other two being CFIm25 (or CPSF5/NUDT21 Cleavage and polyadenylation specificity factor subunit 5 (CPSF5) is an enzyme that in humans is encoded by the ''NUDT21'' gene. It belongs to the Nudix family of hydrolases. The protein encoded by this gene is one subunit of the cleavage factor ...) and CFIm68 (or CPSF6). References Further reading * * * * {{gene-11-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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