User:Pacheco173ayy/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 10-30 nucleotide upstream signaling region of the cleavage site, polyadenylation signal (PAS), 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. '''The mature RNA are transported into the cytoplasm, where they are translated into proteins. '''

Structure
In mammals, CPSF has six subunits: CPSF-73, CPSF-100, CPSF-30, CPSF-160, WDR33, and Fip1.

'''Cleavage stimulation factor (CstF) has three subunits. CstF recognizes the second downstream signaling region of the cleavage site, which is a GU-rich sequence motif.'''

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 directly binds to the AAUAAA polyadenylation signal.

WDR33 and CPSF-30 recognize the polyadenylation signal (PAS) in pre-mRNA, which aids in defining the position of RNA cleavage.

CPSF recruits proteins to the 3' region. Identified proteins that are coordinated by CPSF activity include: cleavage stimulatory factor and the two poorly understood cleavage factors. The binding of the polynucleotide adenylyltransferase responsible for actually synthesizing the tail is a necessary prerequisite for cleavage, thus ensuring that cleavage and polyadenylation are tightly coupled processes.

Genes

 * CPSF1, CPSF2, CPSF3, CPSF4, CPSF6