In genetics, a transcription terminator is a section of nucleic acid sequence that marks the end of a gene or operon in genomic DNA during transcription. This sequence mediates transcriptional termination by providing signals in the newly synthesized transcript RNA that trigger processes which release the transcript RNA from the transcriptional complex. These processes include the direct interaction of the mRNA secondary structure with the complex and/or the indirect activities of recruited termination factors. Release of the transcriptional complex frees RNA polymerase and related transcriptional machinery to begin transcription of new mRNAs.
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.
Exonucleases are enzymes that work by cleaving nucleotides one at a time from the end (exo) of a polynucleotide chain. A hydrolyzing reaction that breaks phosphodiester bonds at either the 3′ or the 5′ end occurs. Its close relative is the endonuclease, which cleaves phosphodiester bonds in the middle (endo) of a polynucleotide chain. Eukaryotes and prokaryotes have three types of exonucleases involved in the normal turnover of mRNA: 5′ to 3′ exonuclease (Xrn1), which is a dependent decapping protein; 3′ to 5′ exonuclease, an independent protein; and poly(A)-specific 3′ to 5′ exonuclease.
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.
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. In eukaryotes, messenger RNA precursors (pre-mRNA) are transcribed in the nucleus from DNA by the enzyme, RNA polymerase II. The pre-mRNA must undergo post-transcriptional modifications, forming mature RNA (mRNA), before they can be transported into the cytoplasm for translation into proteins. The post-transcriptional modifications are: the addition of a 5' m7G cap, splicing of intronic sequences, and 3' cleavage and polyadenylation.
Eukaryotic transcription is the elaborate process that eukaryotic cells use to copy genetic information stored in DNA into units of transportable complementary RNA replica. Gene transcription occurs in both eukaryotic and prokaryotic cells. Unlike prokaryotic RNA polymerase that initiates the transcription of all different types of RNA, RNA polymerase in eukaryotes comes in three variations, each translating a different type of gene. A eukaryotic cell has a nucleus that separates the processes of transcription and translation. Eukaryotic transcription occurs within the nucleus where DNA is packaged into nucleosomes and higher order chromatin structures. The complexity of the eukaryotic genome necessitates a great variety and complexity of gene expression control.
In enzymology, a polynucleotide adenylyltransferase is an enzyme that catalyzes the chemical reaction
Cleavage stimulation factor 64 kDa subunit is a protein that in humans is encoded by the CSTF2 gene.
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.
Cleavage and polyadenylation specificity factor subunit 2 is a protein that in humans is encoded by the CPSF2 gene. This protein is a subunit of the cleavage and polyadenylation specificity factor (CPSF) complex which plays a key role in pre-mRNA 3' end processing and polyadenylation. The CPSF2 protein connects the two subunits of the complex, mCF and mPSF. Its structure contributes both to the stability of the subunits interaction and to the flexibility of the complex necessary for function. This protein has been identified as an essential subunit of the complex as certain mutations in the region inhibit CPSF complex formation.
Poly(A) polymerase alpha is an enzyme that in humans is encoded by the PAPOLA gene.
Cleavage stimulation factor 50 kDa subunit is a protein that in humans is encoded by the CSTF1 gene.
Cleavage stimulation factor 77 kDa subunit is a protein that in humans is encoded by the CSTF3 gene.
Cleavage stimulation factor 64 kDa subunit, tau variant is a protein that in humans is encoded by the CSTF2T gene.
Cleavage and polyadenylation specificity factor subunit 3 is a protein that in humans is encoded by the CPSF3 gene.
Cleavage and polyadenylation specificity factor subunit 4 is a protein that in humans is encoded by the CPSF4 gene.
Cleavage and polyadenylation specificity factor subunit 6 is a protein that in humans is encoded by the CPSF6 gene.
Integrator complex subunit 11 is a protein that in humans is encoded by the CPSF3L gene.
Poly(A) polymerase gamma is an enzyme that in humans is encoded by the PAPOLG gene.
Cleavage and polyadenylation specificity factor subunit 7 is a protein that in humans is encoded by the CPSF7 gene.
