In the situation where Ki< K1, This form of mixed inhibition has been termed noncompetitive- uncompetitive inhibition

TLS Online TPP Program

#Id: 1990

#Unit 3. Fundamental Processes

The sequence AAUAAA (hexamer) is a signal for cleavage to generate a 3’ end of mRNA that is polyadenylated.

TLS Online TPP Program

#Id: 1991

#Unit 3. Fundamental Processes

Polyadenylation requires a protein complex that contains a specificity factor, an endonuclease, and poly(A) polymerase.

 

TLS Online TPP Program

#Id: 1992

#Unit 3. Fundamental Processes

Binding of polyadenylation factors takes place when CTD Ser2 phosphorylated.

TLS Online TPP Program

#Id: 1993

#Unit 3. Fundamental Processes

Phosphorylation on Ser2 by P-TEFb activates elongation, splicing and polyadenylation

TLS Online TPP Program

#Id: 1994

#Unit 3. Fundamental Processes

The polyadenylation site has two cis-acting signals: 

An upstream AAUAAA motif, which is usually located 11 to 30 nucleotides from the site  A downstream U-rich or GU-rich element.

TLS Online TPP Program

#Id: 1995

#Unit 3. Fundamental Processes

The AAUAAA is needed for cleavage and polyadenylation because deletion or mutation of the AAUAAA hexamer prevents generation of the polyadenylated 3’ end