Cleavage stimulatory factor or cleavage stimulation factor (CstF or CStF) is a
heterotrimeric
In biochemistry, a protein trimer is a macromolecular Complex (chemistry), complex formed by three, usually covalent bond, non-covalently bound, macromolecules like proteins or nucleic acids. A homotrimer would be formed by three identical molecul ...
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
, made up of the proteins
CSTF1
Cleavage stimulation factor 50 kDa subunit is a protein that in humans is encoded by the ''CSTF1'' gene.
This gene encodes one of three subunits which combine to form cleavage stimulation factor (CSTF). CSTF is involved in the polyadenylation and ...
(55
kDa
The dalton or unified atomic mass unit (symbols: Da or u) is a non-SI unit of mass widely used in physics and chemistry. It is defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at ...
),
CSTF2
Cleavage stimulation factor 64 kDa subunit is a protein that in humans is encoded by the ''CSTF2'' gene.
This gene encodes a nuclear protein with an RRM (RNA recognition motif) domain. The protein is a member of the cleavage stimulation factor (C ...
(64kDa) and
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 one of three (including CSTF1 and CSTF2) cleavage stimulation factors that combine to form the cleavage s ...
(77kDa), totalling about 200 kDa. It is involved in the cleavage of the
3' signaling region from a newly synthesized pre-
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 p ...
(mRNA) molecule. CstF is recruited by
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 ...
(CPSF) and assembles into a
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 c ...
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
The cell nucleus (pl. nuclei; from Latin or , meaning ''kernel'' or ''seed'') is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, h ...
to the
cytosol
The cytosol, also known as cytoplasmic matrix or groundplasm, is one of the liquids found inside cells (intracellular fluid (ICF)). It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondri ...
for
translation
Translation is the communication of the Meaning (linguistic), 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 ...
.
The amount of CstF in a cell is dependent on the phase of the
cell cycle
The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and subs ...
, increasing significantly during the transition from
G0 phase
The G0 phase describes a cellular state outside of the replicative cell cycle. Classically, cells were thought to enter G0 primarily due to environmental factors, like nutrient deprivation, that limited the resources necessary for proliferation ...
to
S phase
S phase (Synthesis Phase) is the phase of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Since accurate duplication of the genome is critical to successful cell division, the processes that occur during ...
in mouse
fibroblast
A fibroblast is a type of cell (biology), biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (Stroma (tissue), stroma) for animal Tissue (biology), tissues, and plays a critical role in wound ...
and human
splenic
The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes . B cells
B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or ...
.
Genes
*
CSTF1
Cleavage stimulation factor 50 kDa subunit is a protein that in humans is encoded by the ''CSTF1'' gene.
This gene encodes one of three subunits which combine to form cleavage stimulation factor (CSTF). CSTF is involved in the polyadenylation and ...
,
CSTF2
Cleavage stimulation factor 64 kDa subunit is a protein that in humans is encoded by the ''CSTF2'' gene.
This gene encodes a nuclear protein with an RRM (RNA recognition motif) domain. The protein is a member of the cleavage stimulation factor (C ...
or
CSTF2T
Cleavage stimulation factor 64 kDa subunit, tau variant is a protein that in humans is encoded by the ''CSTF2T'' gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredi ...
,
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 one of three (including CSTF1 and CSTF2) cleavage stimulation factors that combine to form the cleavage s ...
References
Further reading
* Lodish H, Berk A, Matsudaira P, Kaiser CA, Krieger M, Scott MP, Zipursky SL, Darnell J. (2004). ''Molecular Cell Biology.'' WH Freeman: New York, NY. 5th ed.
External links
*
Protein complexes
Gene expression
RNA-binding proteins
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