Posttranscriptional Gene Regulation by Spatial Rearrangement of the 3′ Untranslated Region
Figure 6
Model for Posttranscriptional Gene Regulation by Spatial Rearrangement of the 3′ UTR
Proper translation termination requires a termination-promoting signal from the poly(A) tail. When the ribosome terminates close enough to the poly(A) tail to receive this signal no NMD occurs, and the mRNA remains intact. If the physical distance between the stop codon and the poly(A) tail is too large to allow transmission of the termination-promoting signal, NMD ensues, resulting in a short half-life and low steady-state level of the mRNA. The physical distance between the stop codon and the poly(A) tail depends on the 3-D structure of the 3′ UTR. The 3′ UTR structure can be reconfigured by altering (i) intramolecular base pairing, (ii) interaction of the mRNA with RNA-binding proteins, and (iii) interactions among the involved proteins through posttranslational modifications.