Functional group substitutions of the branchpoint adenosine in a nuclear pre-mRNA and a group II intron

UMMS Affiliation

Howard Hughes Medical Institute, Program in Molecular Medicine

Publication Date


Document Type



Adenosine; Base Sequence; Guanosine; *Introns; Molecular Sequence Data; RNA Precursors; *RNA Splicing; RNA, Messenger; RNA, Nuclear; Substrate Specificity


Life Sciences | Medicine and Health Sciences


Splicing of nuclear mRNA precursors (pre-mRNAs) takes place in the spliceosome, a large and complex ribonucleoprotein. Nuclear pre-mRNA splicing and group II intron self-splicing occur by a chemically identical pathway involving recognition of a specific branchpoint adenosine and nucleophilic activation of its 2'-hydroxyl group. The chemical similarity between these two splicing reactions, as well as other considerations, have suggested that the catalytic core of the spliceosome and group II introns may be related. Here we test this hypothesis by analyzing splicing and RNA branch formation of a pre-mRNA and a group II intron in which the branchpoint adenosine was substituted with purine base analogues. We find that replacement of the branchpoint adenosine with either of two modified adenosine analogues or guanosine leads to remarkably similar patterns of splicing and RNA branch formation in the two systems.


RNA. 1997 Aug;3(8):861-9.

Journal/Book/Conference Title

RNA (New York, N.Y.)

Related Resources

Link to Article in PubMed

PubMed ID