What is alternative polyadenylation?

Alternative polyadenylation (APA) is a widespread mechanism of gene regulation that generates distinct 3′ ends in transcripts made by RNA polymerase II. APA is tissue specific and globally regulated in various conditions, such as cell proliferation and differentiation, and in response to extracellular cues.

What is polyadenylation used for?

Function. In nuclear polyadenylation, a poly(A) tail is added to an RNA at the end of transcription. On mRNAs, the poly(A) tail protects the mRNA molecule from enzymatic degradation in the cytoplasm and aids in transcription termination, export of the mRNA from the nucleus, and translation.

Which of the polyadenylation site is used in alternative polyadenylation in thyroid cells?

UTR-APA
Alternative polyadenylation occurring at alternative poly(A) sites located in the 3′ UTR of the last exon is called UTR-APA.

What is intronic polyadenylation?

An intronic polyadenylation event is defined as a poly(A) site in a particular intron (5′ss + 3′ss) of a RefSeq or KnownGene mRNA. b. Terminal exon type is the terminal exon resulting from an intronic polyadenylation event.

Where does alternative polyadenylation occur?

In some cases the alternative poly(A) sites are located in internal introns/exons and therefore APA events will produce different protein isoforms, we will refer to this type as CR-APA (Coding Region-APA).

What is the function of the spliceosome?

Abstract. Spliceosomes are multimegadalton RNA–protein complexes responsible for the faithful removal of noncoding segments (introns) from pre-messenger RNAs (pre-mRNAs), a process critical for the maturation of eukaryotic mRNAs for subsequent translation by the ribosome.

What specifies the site of polyadenylation?

Polyadenylation signal The polyadenylation signals are located downstream of the 3′ exons [1]. Example: A POLYA_SIGNAL located 103 bp downstream of the human IGHG3 CH3-CHS exon is used in the transcription of secreted gamma3 chains.

What is Mrna editing or splicing?

RNA editing and alternative splicing are two major RNA processing steps that can introduce significant modifications to the final gene products. By tackling these processes in isolation, recent studies have enabled substantial progress in understanding their global RNA targets and regulatory pathways.

What is the significance of alternative polyadenylation of mRNA transcript?

Alternative polyadenylation (APA) is emerging as a widespread mechanism used to control gene expression. Like alternative splicing, usage of alternative poly(A) sites allows a single gene to encode multiple mRNA transcripts.

What is the role of CPSF in post transcription?

Working as a complex, CPSF recognizes the polyadenylation signal sequence AAUAAA and cleaves the pre-mRNA. This provides sequence specificity that may play an important role in regulating pA site selection, gene expression, cancer cell migration, metastasis, and eventually disease outcome [32].