It's all about splicing ... 3′ end of the intron is brought into proximity, cut, and joined to the 5′ end. This step occurs by transesterification; in this case, an OH group at the 3 ...

Figure 3: A longer than usual distance between the PPT and 3' splice site AG in the wild type msl-2 intron allows for inhibition of splicing by the Drosophila Sex-lethal (SXL) protein.

Heidelberg biochemists and structural biologists from Shanghai unravel the roles of two key regulatory factors in mRNA ...

The spliceosome and Group II introns are believed to share ... released the mRNA that it had finished splicing introns from, it hung onto intron lariats and reshaped them into true circles.