Mechanism for RNA splicing of gene transcripts.

It has been demonstrated that structural genes in eukaryotes contain intervening sequences (introns) which are absent from expressed sequences (exons) [l-6]. There is evidence that intervening sequences are transcribed [7], but subsequently the introns are removed by a process which is now known as RNA splicing [ 8,9]. RNA splicing must be a very precise process since it results in the joining of successive coding sequences to produce an unambiguous message. We wish to propose a mechanism for RNA splicing which depends on intermolecular hybridisation and which is closely analogous to the genetic recombination of DNA molecules. In both processes the point at which the breakage and reunion of polynucleotide genes occurs is determined by the base pairing of complementary sequences (hybrid DNA or hybrid RNA). In this way the addition of extraneous nucleotides or the deletion of essential nucleotides is prevented.