Splicing of plant pre-mRNAs in animal systems and vice versa.

To investigate similarities and differences of pre-mRNA splicing between higher plants and animals, we tested whether pre-mRNAs of higher plants can be accurately spliced in animal systems, and whether an animal pre-mRNA can be spliced in plant cells. Pre-mRNAs of the maize bronze locus and oat phytochrome type 3 are accurately spliced with moderate efficiency in a human (HeLa cell) nuclear extract. The first intervening sequence (IVS1) of bean phaseolin pre-mRNA is not excised in the human nuclear extract, but is removed (although at low efficiency) in intact monkey cells. However, the IVS1 of human alpha-globin pre-mRNA is not removed in tobacco cells. Our data suggest that the mechanisms of pre-mRNA splicing are similar, but not identical, in plants and animals.