ALTERNATIVE SPLICING OF THE EUGLENA-GRACILIS CHLOROPLAST ROAA TRANSCRIPT

A novel gene, roaA (ribosomal operon-associated gene), encoding a pote ntial RNA-binding protein has been identified in the rp123 ribosomal p rotein operon of the Euglena gracilis chloroplast genome. The roaA gen e is interrupted by one group II and three group II introns. Introns 1 and 2 of roaA can be interpreted as a twin tron, formed from the inse rtion of a group II intron into the 5' splice site of a group III intr on. Alternative splicing of the group Ill intron results in two distin ct transcripts encoding proteins of 516 and 514 amino acids. Group Ill introns may play a role in the generation of alternatively spliced tr anscripts.