Figure 1.

Insertions in fungal PRP8 genes encode full-length inteins. The splicing and homing endonuclease domain motifs of ascomycete VMA inteins aligned with PRP8 inteins present in public databases. A. Alignment of the N-terminal splicing domains (blocks A and B; see InBase [62]. B. Alignment of the C-terminal splicing domains (F and G). C. An alignment of the four homing endonuclease domains (blocks C, D, E, H; see InBase) of the full-length PRP8 inteins and the active ascomycete VMA inteins. A region of variable length is indicated between blocks C and D together with the number of residues removed from the alignment. Accession numbers in the NCBI/protein database for the VMA inteins are SceVMA PXBYVA; ScarVMA, CAC86344; ZbaVMA, CAC86348.1; CtrVMA, A46080. Sequences of PRP8 inteins can be found at InBase and/or from accession data in Table 1. The taxonomic relationships of the species are also summarised in Table 1.