Synthetic donor and acceptor splice sites function in an RNA polymerase B (II) transcription unit.

We have synthesised a 32-bp oligonucleotide containing sequences conforming to the consensus sequences for donor and acceptor splice sites. The oligonucleotide has been inserted into an RNA polymerase B (II) transcription unit and the resulting recombinant used to study the splicing mechanism. Our findings are as follows: (i) the synthetic sites function when separated by several different prokaryotic or eukaryotic DNA fragments providing bulk intron sequence, (ii) intron size need not be greater than 29 bp, (iii) an AG dinucleotide 11 bp upstream from the invariant AG of an acceptor splice site renders the latter non-functional, and (iv) sequence changes distant from splice sites can affect the efficiency of their utilisation.